RMP Grounding Manual

PERSONAL PROTECTIVE GROUNDING PROCEDURES MANUAL Revised: November 14, 2019 PolicyTech v. 2 Five to Stay Alive 1. Identify 2. Isolate 3. Test 4. Bond 5. Ground Grounding Manual for UTAH, IDAHO and WYOMING Prepared by the Joint Grounding Committee (Kevin Freestone, Lane Maxfield, Bret Rich, Scott Wardrop, Alan Wayment; consultant Brain Erga)

PERSONAL PROTECTIVE GROUNDING PROCEDURES MANUAL Table of Contents PREAMBLE................................................................................................................................................ 3 1 Purpose ................................................................................................................................................. 3 2 References............................................................................................................................................. 3 2.1 Industry References......................................................................................................................... 3 2.2 Company References ...................................................................................................................... 4 3 DEFINITIONS ..................................................................................................................................... 4 4 INTRODUCTION................................................................................................................................ 9 5 SUBSTATION, TRANSMISSION AND DISTRIBUTION GROUNDING PROCEDURES .... 10 5.1 Developing an Equipotential Zone (EPZ)..................................................................................... 10 5.2 Bracket Grounding........................................................................................................................ 11 5.3 Grounding Precautions.................................................................................................................. 11 5.4 General Requirements................................................................................................................... 12 5.5 Voltage Detection.......................................................................................................................... 13 5.6 Bridging Conductor Open Points .................................................................................................. 13 5.7 Step and Touch Potential .............................................................................................................. 14 5.8 Grounding Procedures Exceptions................................................................................................ 14 5.9 Protective Grounding Equipment.................................................................................................. 14 5.10 Inspections .............................................................................................................................. 15 5.11 Clean Connections .................................................................................................................. 15 6 PERSONAL PROTECTIVE GROUNDING OF OVERHEAD DISTRIBUTION LINES AND DEVICES................................................................................................................................................... 16 6.1 PPG Away From the Work Location ............................................................................................ 17 6.2 PPG When Distribution Conductors Are Down or Broken and On the Ground........................... 18 6.3 Splicing or Opening Distribution Conductors............................................................................... 19 6.4 Working with De-Energized Distribution Conductors at Ground Level ...................................... 19 6.5 Grounding Overhead Distribution Capacitors............................................................................... 19 7 TRANSMISSION GROUNDING PROCEDURE .......................................................................... 20 7.1 Clearance/Terminal Clearance ...................................................................................................... 20 7.2 PPG of Overhead Transmission Lines and Devices...................................................................... 21 7.3 Grounding for Transmission Lines with Distribution Underbuild................................................ 22 7.4 Series Capacitors and Shunt Reactors........................................................................................... 23 7.5 Shield Wires and OPGW .............................................................................................................. 23 7.6 Steel Structures ............................................................................................................................. 24 7.7 Aerial Splicing or Opening Transmission Conductors ................................................................. 24 7.8 Working with De-Energized Transmission Conductors at Ground Level .................................... 25 7.9 Ground Switches ........................................................................................................................... 26 7.10 Determining Step and Touch Potential ................................................................................... 26 7.11 Reducing Step and Touch Potentials ...................................................................................... 27 7.12 Multiple Crews Working the Same Transmission Line Where Induced Currents and Voltages are Present to Parallel Transmission Lines .............................................................. 27 Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 1 of 50

7.13 Multiple Crews Working on the Same Transmission Line Where No Induced Currents and Voltages are Present...................................................................................................................... 27 8 UNDERGROUND GROUNDING PROCEDURES....................................................................... 28 8.1 Grounding Insulated Power Cable ................................................................................................ 28 8.2 Underground Cable Splicing and Adding Terminations............................................................... 30 8.3 Bare Concentric Cables................................................................................................................. 31 8.4 Working URD Cable Using the Isolation Method ........................................................................ 31 8.5 PPG of URD Cable Using the EPZ and Isolation Method............................................................ 32 8.6 Opening the Concentric Neutral.................................................................................................... 33 8.7 PPG of Cable Using the Insulation Method.................................................................................. 33 8.8 Isolation Method for Cable Replacement in Existing Equipment................................................. 34 8.9 Methods of Grounding High-Voltage Cable................................................................................. 35 8.10 Fault Finding........................................................................................................................... 36 9 SUBSTATION AND SWITCHYARD GROUNDING PROCEDURES ...................................... 37 9.1 Policy ............................................................................................................................................ 37 9.2 Clearance/Terminal Clearance ...................................................................................................... 37 9.3 Specifications ................................................................................................................................ 37 9.4 Grounding Practices...................................................................................................................... 37 9.5 Special Grounding Situations........................................................................................................ 38 9.6 Testing........................................................................................................................................... 39 10 MECHANICAL GROUNDING EQUIPMENT ............................................................................. 40 10.1 Electrical Protection Working with Insulated Booms............................................................. 40 10.2 Electrical Protection Working with Noninsulated Booms ...................................................... 41 11 GROUNDING DURING STRINGING OPERATIONS................................................................ 43 APPENDIX A ............................................................................................................................................ 45 Electric Field Induction and Magnetic Field Induction Introduction .................................................. 45 Electric Field Induction ....................................................................................................................... 45 Magnetic Field Induction..................................................................................................................... 46 Electric Induction and Atmospheric Static Charge.............................................................................. 48 APPENDIX B ............................................................................................................................................ 49 Underground Cable Grounding ........................................................................................................... 49 Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 2 of 50

PERSONAL PROTECTIVE GROUNDING PROCEDURES MANUAL PREAMBLE The grounding committee, established in June 1985, was given the responsibility of developing a companywide personal protective grounding (PPG) procedure and training program, for affected Rocky Mountain Power qualified employees. Personal protective grounding (PPG), also called “creating an equipotential zone,” is an accepted industry method of protecting employees working on, or near, de-energized lines and equipment. If an accidental re-energization of the line or equipment was to occur, the employees would be protected if temporary PPG equipment is properly installed. Also, the development of electric field induction or magnetic field induction can occur in today’s electrical transmission system, which can create hazards for electrical workers if not properly identified and controlled. No grounding method can be considered entirely safe, but the work methods detailed in this manual are the latest industry-accepted PPG methods. This manual is a living document and will be updated as new procedures and equipment are developed. 1 PURPOSE This procedure covers the work methods for protecting workers from voltages and currents that might develop at a de-energized worksite during operation, maintenance and construction of overhead and underground, transmission, distribution and substation lines, cables and equipment. Though the primary work method covered by this procedure is the use of a PPG system, insulation or isolation work methods may be used as an alternative in some isolated incidences — when approved by the safety department. 2 REFERENCES 2.1 Industry References ASTM F855 Standard Specifications for Temporary Protective Grounds to Be Used on De-energized Electric Power Lines and Equipment IEEE 1048 – 2016 Guide for Protective Grounding of Power Lines IEEE/ESMOL Task Force 15.07.09.01 Worker Protection While Working De- energized Underground Distribution Systems IEEE/ESMOL Task Force Induction Hazards on De-energized Electric Utility Systems OSHA 1910.269(m) De-energizing Lines and Equipment for Employee Protection OSHA 1910.269(n) Grounding for the Protection of Employees Induced Voltage & Current Simulations, Safety Criterion, and Mitigations for EHV Transmission Lines in Close Proximity, IEEE Transactions on Industry Applications, Vol. 55, Issue 3 (11 February 2019) Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 3 of 50

2.2 Company References Accident Prevention Manuals Facility WorkZone Safety FR Clothing Card Protective Grounding on OPGW Rocky Mountain Power Switching and Clearance Procedures 3 DEFINITIONS Accidental closing — Although all sources of a de-energized line must be visibly open, clearance tags installed, and a clearance issued before work is started, the possibility of human error exists with inadvertent closing-in of an energized circuit. Backfeed — Energy introduced to a circuit unintentionally. Particularly a hazard during outages. Bagging — The process of using rope and a link stick rated for the voltage to secure each individual air break switch contact blade in a manner that the switch cannot possibly be closed. Barricade — Physical obstructions such as tapes, screens, and/or cones intended to warn about and limit access to a hazardous area. Bond, Bonded — The mechanical interconnection of conductive parts to maintain a common electrical potential. Bracket grounding — A grounding method where a set of tripping grounds are installed on both sides of a worksite, typically on one structure from the worksite (not for worker protection). Cable isolation — A process of isolating both ends of the conductor and concentric neutral, and/or shield from the system neutral and energized sources. Jacketed cable can be considered isolated if the bare concentric neutral ends of the cable are isolated from all ground sources. Capacative charge — The ability to collect and store an electrical charge. Capacitive coupling (electric field induction) — The process of generating a voltage and current in an ungrounded conductive object (ungrounded conductor or equipment) by means of time-varying electric fields, generated from an AC voltage applied to a line or equipment. Circulating current — A powerline will induce current on a nearby isolated conductor when that conductor forms part of a circuit. Grounding a conductor on each side of a work zone (bracket grounding) will create a circuit through the conductor, down one set of grounds, through the earth, and back up the other set of grounds. The first set of grounds installed on an isolated conductor will collapse the induced voltage from the electric field. A second set of grounds will create a circuit which will cause an induced current to flow from the magnetic field. Clearance — A guarantee issued by the region system/grid operator that a circuit has been de-energized and tagged out (at visual open points) and will remain de-energized until the Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 4 of 50

qualified until the qualified person receiving the clearance releases it. A clearance is given only when all known possible sources for energizing the circuit have been switched open, locked if the equipment allows and tagged out. Circuits covered by clearances cannot be re- energized through the tagged switch, even by the qualified person issued the clearance, until directed to do so by the region system/ grid operator. Clearance (personal) — A self-protecting guarantee taken by an electrically qualified person that a live circuit has been de-energized and tagged out at visual open points at the normal sources and remains that way until the responsible person establishing the personal clearance removes it. Open points covered by the personal clearance cannot be energized through the tagged switch(s), even by the responsible person holding the personal clearance until formal communication has taken place between all employees associated with the work. Clearance (terminal) — A guarantee issued by the region system/ grid operator that a device has been opened and tagged out at a visual open point(s) at the normal sources, and remains open until the person receiving the terminal clearance releases it. Devices covered by terminal clearances cannot be energized through the tagged switch(s), even by the person issued the terminal clearance, until directed to do so by the controlling region system/grid operator. Terminal clearances are issued to foreign utilities where a PacifiCorp region system/grid operator is only in control of PacifiCorp's end of a line (typically transmission lines) or when a clearance cannot be issued because the region system/grid operator cannot control all locations where a circuit could be energized (typically distribution lines). Terminal clearances are issued to a device so this makes them device specific. Cluster bar — A terminal temporarily attached to a structure, and used to assist in developing an equipotential zone (EPZ). It also provides a connection point for two or more grounding clamps. Conductor — Used in the context of an electrical apparatus, refers to the overhead lines or underground cable that conducts electricity from one point to another. A broader definition is any material that has the potential to conduct electricity. DC Hi-Pot — A DC hi-pot tool is a device that will help determine if a section of underground residential cable contains a fault. De-energized — Lines or equipment that are disconnected from all intentional sources of electrical supply by opening switches, jumpers, taps, elbows or other means. De-energized lines and equipment could still be electrically charged or energized through various means, e.g. induction from energized circuits, portable generators or lightning. De-energizing lines and equipment does not allow workers to enter the minimum approach distance (MAD) unless live line work methods or the PPG work methods in this procedure are followed. De- energized does not mean it is grounded and safe to work. Electrical apparatus — Any equipment, conductive apparatus, transformer, capacitor or conductor that is used to establish an electrical connection to the broader electrical system. Electrical field induction — A charge that is created on a conductive material, including power lines, through capacitive coupling that is created through proximity to another energized conductor. Energized — Electrically connected to a source of potential difference, or electrically charged so as to have a potential different from that of the earth. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 5 of 50

Equipotential zone (EPZ) — The process of developing and maintaining a near zero potential difference between two or more points, such as lines, equipment, and structures. When work takes place at a site where a second point of contact is possible, an EPZ must be put in place. The EPZ does not extend below the cluster bar. The EPZ does not extend outside of the ground mat. Exposure voltage — The voltage impressed across a worker’s body, either hand-to-hand, or hand-to-foot, when the worker comes in contact with objects within the worksite that are not at the same potential. Fuzzing, teasing or buzzing — Fuzzing, teasing or buzzing occurs when a worker uses a live-line tool to hold a wrench or similar item near a line and then listens for buzzing sound given off as the tool approaches an energized circuit part. Ground, ground source — A conducting connection, whether intentional or accidental, where a line(s) or equipment are connected to earth, or to some conductive body of relatively large extent that serves in place of the earth, resulting in the line(s) or equipment being grounded, i.e. common neutral, system neutral, pole or tower ground, anchor rod or ground rod. Ground (noun) — A conductive connection by which an electric circuit or equipment is connected to a reference ground. Ground grid — A system of interconnected conductors arranged in a pattern over a specified area such as a substation. Ground mat — A temporary or permanent conductive mat that is grounded. Used to create an EPZ for switching and for such cases as splicing conductors or working around pad- mounted equipment. Ground potential rise (GPR) — A voltage measured between an energized structure or ground electrode, and a remote point on earth’s surface having zero or nearly zero potential. Ground potential rise occurs anytime current is injected into the earth through a structure or ground electrode. This leads to step and touch potentials. Ground reference — A conductive body, usually earth, to which an electric potential is referenced. Grounded (verb) — Intentionally connected to earth through a ground connection or connections having sufficient current-carrying capacity. Guarded — Protected by personnel; or covered, fenced or enclosed by means of suitable casings, barrier rails, screens, mats, platforms or other suitable devices in accordance with effective barricading techniques designed to prevent approach or contact to hazards by persons or objects. Note: Wires, which are insulated but not otherwise protected, are not considered guarded. Inadvertent movement (“M”) — A distance added to MAID to equate MAD. The distance allows a qualified worker to make an accidental movement toward an exposed, energized line or equipment, realize their error, and retract their body part before entering the MAID. Insulation — A form of worker protection where insulating material, designed, rated and tested per ASTM standards for the anticipated maximum voltage is placed between the Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 6 of 50

worker and conductors or equipment eliminating physical contact (high-voltage rated gloves, rubber blankets, insulated tools, insulated shields and insulated covers). Insulated mat — A mat designed to be an insulated barrier from earth ground to a ground mat or equipment. The purpose of the mat is to eliminate step potential hazards. An insulated mat can be constructed out of rubber or fiberglass, in a substation it may be constructed of wood or fiberglass deck with vertical post insulators supports. Isolated — Conductors or facilities that cannot be energized by the closing of a switch or jumper, and which, in the judgment of the person in charge, cannot be exposed to any form of accidental energization such as accidental contact, induction from other conductors, or backfeed. Live line or hot line tools — Tools that are especially designed and maintained for work on energized lines and equipment or used to apply temporary protective grounding equipment. Magnetic field induction (electromagnetic coupling) — The process that employs both electric and magnetic fields to generate a circulating current between two grounded sites of a line due to the proximity of an adjacent or nearby energized line carrying AC current. Magnetic flux — The total magnetic induction crossing a surface, equal to the integral of the component of magnetic induction perpendicular to the surface over the surface. Minimum air insulation distance (MAID) — The shortest distance in air between an energized line or equipment and a conductive body at different potential. This distance is not affected by a floating electrode in the gap, or any factor for inadvertent movement. Minimum approach distance (MAD) — The minimum air insulation distance (MAID) plus a factor for inadvertent movement. Overhead static wire, optical ground wire (OPGW) — Grounded wire placed above phase conductors for the purpose of intercepting and protecting phase conductors from direct lightning strikes. Personal protective grounding (PPG) — A grounding method where temporary protective grounding jumpers are installed in a manner that bonds the ground source, structure, phase conductor(s), and all other conductive objects within the worksite together, limiting the exposure voltage to a safe value, and creating an EPZ. Protective grounding equipment — A system of ground clamps, ferrules, cluster bar(s) and cables designed for carrying an anticipated fault current, for a set period of time, as specified in ASTM F855. Notes: Install PPG as short, straight and direct as practical. The minimum size ground for distribution work is 2/0. The minimum size ground for transmission work is 4/0. Protective grounding jumper — A single assembly designed and rated, per ASTM F 855, for the anticipated current. It is constructed from variable-length grounding cable, clamps and ferrules, and is used to temporarily bond two conductive points together. Qualified worker — A person who has received training or instruction who has demonstrated proficient knowledge of construction standards, operations, policies, practices and the hazards associated with the tasks performed within their job responsibilities. OSHA uses the term competent person. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 7 of 50

Remote ground source — The best practical ground, i.e. nearby neutral, an electrical circuit by which other voltages are measured, resident ground switch, or grounding at the substation. Remote transferred potential — This is the voltage resulting from touching a conductive element that is connected to a remote component at a different potential. It could be thought of as standing on a remote earth spot while holding a long wire that becomes energized on its far end. Touch potential between the remote site and the v potential where the worker stands can be quite different. Responsibility — Each employee working on electrically isolated lines and equipment is responsible for knowing grounding requirements and applying the proper procedure(s) Second point of contact — Any conductive path for electrical current if the worker comes in contact with a source of electrical energy. Series — Creating a path for current to flow through your body. Shall, must, should — Shall and must are used to indicate provisions that are mandatory. Should is used to indicate provisions that are not mandatory, though preferable. Shepherd’s Hook — This is a long, insulated handle with a large hook on one end. Near the hook is a rope pulley. The hook is placed over the bus and the rope is connected to the clamp to be landed on the bus. A second worker guides and tightens the clamp using an shotgun hot stick. Single point ground — Each conductor is bonded individually to a visible common ground point. Static charge — A static charge can accumulate on an isolated de-energized transmission conductor by influences such as a High Voltage Direct Current (HVDC) circuit, wind, cloud movement or solar flares. Step potential — This is the difference in potential from one foot of a worker to the other foot. This can be felt when a worker steps across an energized path of soil/earth. The worker forms a parallel path to the earth and the current flows through the worker as well as the soil/earth. In the event of a fault to ground, the potential on the earth rises greatly at the contact site but falls off sharply as the distance from the fault increases. The resistance of the earth current path decreases as more of the earth is involved and the current can dissipate through a larger cross section. For this reason, workers should not stand near ground rods, which should be barricaded or away from the work zone. The level of step potential is proportional to the available fault current, soil resistivity, line voltage and distance to the ground source. Touch ground — The process of making a firm brief connection to discharge stored energy using a grounded jumper. Touch potential — This is the difference in voltage level between energized electrical lines or equipment and the soil/earth. This may be felt by a worker standing on the ground when the worker contacts the electric lines or equipment and completes a parallel path to earth. Under fault conditions, accidental energization or induction, current may flow through the worker. Workers at ground level shall not come into contact with grounding conductors and shall not touch or lean up against poles, towers or grounded equipment connected to the temporary grounding system. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 8 of 50

Tripping grounds — Protective grounding jumpers installed in a manner that bonds the ground source, phase conductor(s) and/or equipment together. Tripping grounds do not create an EPZ and are not used for worker protection; they are installed to trip the circuit breaker or fuse protection. Verify de-energized — A critical part of working with any conductor is to verify that the line or equipment is de-energized using a voltage tester to test for voltage on the conductor about to be worked. This shall be done immediately preceding all de-energized work. Not performing “verify de-energized” procedures has led to serious and possibly lethal safety incidents. Voltage detector or potential indicator — A device to detect for lack of voltage or potential. Any buzzing, fuzzing or teasing cannot be used. The voltage detector shall be tested before and after each use, using the test button on the device, to ensure the equipment is working properly. Voltage induction — The process of generating a voltage or a current in an isolated conductive object or electric circuit by means of electric fields. Working grounds — See tripping grounds Worksite — The area where worker(s) will be positioned while contacting, or potentially contacting de-energized lines and equipment. 4 INTRODUCTION The electric utility industry has three accepted work methods for employees working within the Minimum Approach Distance (MAD) of energized or de-energized lines and equipment. They are:  Insulation  Isolation  Personal Protective Grounding and Equipotential Zone (PPG and EPZ) Insulation — Workers can insulate themselves from any possible potential difference between lines, equipment and ground using high-voltage rated gloves, insulated tools, insulated platforms, etc. Isolation — Workers can use the isolation method when working on lines and equipment by first grounding them with an approved method, then removing the grounds and isolating the line or equipment. To use the isolation method the lines and equipment must have met the following:  Previously been de-energized under the provisions of Rocky Mountain Power’s switching and clearance procedures, contained in the Accident Prevention Manual, outage coordination software, and region system/grid operator switching orders  No possibility of contact with another energized item Note: The isolation method for transmission and distribution systems may be an acceptable work method when standard grounding procedures are impractical or create a greater hazard, if the work methods detailed in this procedure are followed. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 9 of 50

PPG and EPZ — Workers can install PPG at the worksite to limit the voltage difference between any two accessible points within the worksite to a safe value. Note: A majority of incidents that occur in the electrical industry today are from the failure to properly identify, isolate, test de-energized, bond and ground (Five to stay alive) the system to be worked. The last step, grounding, is the most important part of the process. Grounding is the only method to ensure a conductor remains de-energized for worker protection. Examples when EPZs may be needed include but are not limited to:  Atmospheric conditions  Electrostatic charges (HVDC)  Backfeed  Lightning strikes  Contact with other lines/phases  Potential rise on the neutral or due to line crossings or shield wire due to a fault defective hardware/equipment elsewhere  Static charge failure  Step and touch potentials  Electric field induction  Switching errors (capacitive coupling)  Electromagnetic induction (inductive coupling) 5 SUBSTATION, TRANSMISSION AND DISTRIBUTION GROUNDING PROCEDURES 5.1 Developing an Equipotential Zone (EPZ) When a worker must enter the MAD of de-energized lines and equipment, electrical industry best practices specify the use of a PPG procedure that develops an EPZ, unless insulated or isolated work methods are used. The development of an effective EPZ includes bonding all accessible conductors, structures, components and equipment together through low-resistance paths using properly sized protective grounding equipment. Protective grounding equipment includes grounding cable, ferrules, clamps, cluster bars, and temporary grounding mats. When a worker is positioned within an EPZ, their body is in parallel with the protective grounding equipment. The development of an EPZ limits the exposure voltage across the worker’s body if the lines or equipment become accidently energized. The exposure voltage across, and the current through, the worker is determined by the fault current multiplied by the total resistance of the temporary grounding equipment. The exposure voltage generated across the temporary grounding equipment will be equal to the exposure voltage across the worker during the fault. If the protective grounding equipment is properly sized and properly installed the exposure voltage across, and the current through, the worker will be well below hazardous levels. The worker’s entire body must be within the EPZ when contact is made with lines, equipment and structure components connected into the EPZ. At no time should the worker place their body in series with temporary grounding equipment, or contact lines, equipment and structures not bonded into the EPZ. Mechanical equipment involved in the tasks (bucket trucks, cranes, underground [UG] transformers, UG cable pulling apparatus, etc.) should also be included in the development of the EPZ. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 10 of 50

When a worker is working on or near wood, concrete and fiberglass structures, a cluster bar must be installed around structure. The cluster bar must be bonded into the EPZ and installed below the worker’s feet and as close as is feasible to the worker’s feet. If work is performed off a steel structure, the steel structure is the “cluster bar” and all protective grounding equipment should be bonded from the steel structure to each phase conductor. The worker’s exposure voltage increases as the worker moves away from the protective grounding equipment at the worksite. Depending on the total impedance of the protective grounding equipment and fault current, the exposure voltages may exceed allowable levels as little as 5 to 10 feet from the worksite. Work procedures may not allow the development of a PPG procedure at the worksite. Tripping grounds may be installed no more than one span from the worksite, with a cluster bar and bond to the ground source at the worksite. When any protective grounding procedure is constructed, workers on the ground may be exposed to ground potential rise (GPR) during accidental energization, and where magnetic and/or electric field induction levels are high. Workers on the ground should be positioned a minimum of 5 to 10 feet from the bottom of the structure, and/or the use of conductive or insulating mats and high-voltage rated gloves should be considered. All system ground connections (pole ground, common neutral, grounded static wire, case grounds, etc.) within the worksite should be checked and must be in good condition, e.g., no loose connections, no corrosion, no damaged components etc. The use of a PPG procedure that develops an EPZ is the safest method of protecting workers. However in some cases, the use of a PPG procedure will not work; in these situations live line work methods or the isolation method must be used. 5.2 Bracket Grounding Bracket grounding is a process of installing tripping grounds on both sides of the worksite. When bracket grounding is used, a PPG procedure creating an EPZ at the worksite must also be constructed. 5.3 Grounding Precautions  Ensure the protective grounding equipment is rated for the available fault current and clearing time at the worksite.  Approved live line work methods, such as the live line tools, high-voltage rated glove work methods or other industry-accepted work practices shall be followed when a PPG procedure and the development of an EPZ cannot be achieved.  Live line tools shall be used for connecting and disconnecting protective grounding jumpers and bonds. o DO NOT ‘slide’ or move temporary grounding jumpers grounds with your hands  Temporary ground rods shall be used only when no other ground source is available, and should be considered a last choice. If a temporary ground rod is used it shall be driven a minimum of 6 feet into the ground. Temporary ground rods should not be accessible by the public and should be located 20 feet or more from Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 11 of 50

workers on the ground. Industry studies have shown temporary ground rods provide limited worker protection, but occasionally are the only and best ground source available.  Protective grounding equipment shall be installed as short, straight and direct as is practical.  Non-insulated guy wires shall be bonded into the EPZ if they enter the EPZ.  Workers outside of the EPZ shall avoid contacting any portion of the installed temporary protective grounds unless live line work practices are used.  Ground rods should not be accessible by the public and should be located just outside of the work zone.  The step and touch potentials can also be reduced by choosing the lowest impedance connections. 5.4 General Requirements When lines and equipment that are or may be energized at 600 volts and above are removed from service for operation, maintenance or construction, they shall be considered energized until a clearance has been issued (or a personal clearance is established) and the lines and equipment have been: Tested and Grounded As Specified In This Procedure Lines and equipment shall be tested and grounded only after proper clearances have been issued as specified in the Rocky Mountain Power’s Accident Prevention Manual/Clearance and Switching Procedures. A tailboard meeting shall be held at the work site with all workers involved before beginning any job to discuss the potential hazards. A Rocky Mountain Power tailboard form shall be filled out and signed before work begins. When the work includes grounding of lines and equipment, the use of PPG specific to the site and/or the work shall be discussed by everyone involved with the work. Depending on work location, the lines and equipment shall be connected to the best available ground source. On Rocky Mountain Power’s multi-grounded wye system, the system neutral shall be used as the ground source. If a system neutral is not available use the best available ground source show in Table 1, in order of preference: Table 1 — Ground Sources (if a system neutral is unavailable) 1 Substation ground grid 2. Multi-grounded common neutral system 3. Overhead multi-grounded static wire 4. Structure ground (pole ground, tower ground, footing ground) 5. Remote ground (foreign utility) 6. Anchor rod 7. Ground rod Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 12 of 50

Place the PPG assemblies to minimize the total resistance in parallel with the worker. The ground-end of the protective grounding jumper shall always be connected to the ground source or voltage zero level first and removed last. Order of connections: 1. Connection to tower 2. Connection to best available ground 3. Best available ground to nearest phase conductor 4. Nearest phase conductor to the next closest phase conductor 5. Next closest phase conductor to furthest phase conductor Factors that affect the installation of protective grounds:  Protective grounding clamps shall not be installed over armor rod or preformed conductor ties.  Protective grounding equipment can violently whip when energized with high fault currents. Protective grounding jumpers should be as short as possible and routed to ensure they do not injure workers if energized. Any excess protective grounding jumper length should not be coiled, but tied off to a structure with rope.  When making the connection of the protective grounding jumper to the ungrounded line or equipment, ensure the protective grounding jumper does not contact any part of the worker’s body.  Do not ground through fuses, transrupters, power circuit breakers, switches, power transformers and other similar equipment. 5.5 Voltage Detection A Rocky Mountain Power-approved and tested voltage detector, rated for the system voltage, shall be used to verify the line or equipment is de-energized. Fuzzing, teasing or buzzing the line is NOT an approved method of testing lines or equipment. The voltage detector shall be tested before and after each use, using the test button on the device, to ensure the equipment is working properly. 5.6 Bridging Conductor Open Points There is always a risk that a difference of potential could exist between conductor open points even when temporary protective grounds are installed on both sides of the open point. If a worker’s body bridges the open point, it would create a path for current to flow. For overhead conductors, jumpers shall be installed across any open points of a grounded circuit. At no time shall a worker bridge an open point of grounded overhead conductors. To ensure grounding continuity when opening or closing double deadends, shield wires or floating insulator locations either:  Ground both sides of the worksite and connect both grounding conductors to the structure.  Install a direct bypass jumper of equal or greater ampacity across the open point. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 13 of 50

When disconnecting a double deadend jumper to create an isolation point, make sure that the jumper ends are secured in a manner to prevent them from contacting the structure. 5.7 Step and Touch Potential Workers on the ground may be exposed to GPR even when all types of PPG procedures are used. While work is in progress, workers on the ground should stay at a minimum of 3 feet from a distribution pole, and 10 feet from a transmission structure being worked and also 20 feet from any driven ground rod. If ground workers must contact the structure, approved insulated personal protective equipment (PPE) and insulated mats must be used. The use of ground mats to create an EPZ is also allowed. 5.8 Grounding Procedures Exceptions EXCEPTION 1: When grounding is impractical or more hazardous than working on the lines or equipment without grounds, the grounds may be omitted provided that all work is done as if the line or equipment was energized. EXCEPTION 2: Equipotential grounding and bonding is not required if an overhead conductor is isolated and is free of all sources of electrical potential and if it has two visible open points on each side of the worksite such that all possible sources of energy from accidental energization are eliminated including backfeed. Note: A conductor will never be free of all electrical sources if there are parallel energized conductors inside of the open points, due to induction. In this case the conductor must be grounded. 5.9 Protective Grounding Equipment Only approved protective grounding equipment shall be used when grounding lines and equipment. Approved protective grounding equipment for use on Rocky Mountain Power’s electrical system is specified in Table 2, below. Table 2 specifies the protective grounding cable size that shall be used for each electrical system. Ferrules and clamps must carry equal or greater amp ratings than the cable that they are used with in an assembly. Normal work practices preclude constructing PPG. Extending the PPG can be achieved by using interconnecting cable. The interconnecting cable must be rated equal to or greater than the grounding cables being used. Table 2 — Approved Protective Grounding Equipment Distribution 2/0 Cu Substation 4/0 Cu and 2/0 Cu (See Note 2) Transmission 4/0 Cu and 2/0 Cu (See Note 3) Note 1: The cable sizes specified in Table 2 are the minimum for PPG. Note 2: 2/0 Cu is acceptable under certain applications (see specifications in Section 6, Substation and Switchyard Grounding Procedures). When the substation bus has an available fault duty of 40 kA or below, a single 4/0 copper protective grounding jumper, or parallel 2/0 copper protective grounding jumper shall be used. When the substation bus has an available fault duty of more than 40 kA, parallel 4/0 copper protective grounding jumpers shall be used. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 14 of 50

Note 3: 2/0 Cu approved for use on 1/0 Cu or smaller wire. Parallel 2/0 Cu is equivalent to one 4/0 Cu. When paralleling protective grounding jumpers, both protective grounding jumpers shall be made of the same materials, be the same length, and the grounding clamps shall be installed within 3 inches of each other. 5.10 Inspections Protective grounding equipment shall be inspected before each use. This includes a visual review of protective grounding jumpers for broken or loose fittings, and chafed or cut insulation. The grounding clamp jaws shall be clean and the cable ferrules tightened if required. The grounding clamp jaws should be wire brushed before each use. If any damage is found, repair or replace the equipment. Pay specific attention to the following:  Check the condition of the cable at each ferrule.  Assess the ability of the clamps to close tightly.  Evaluate the general mechanical condition of the hardware.  Inspect all connections, nuts and bolts, or clamps and ferrules for tightness.  Verify personal grounds and ground clamps have a current inspection sticker attached. Other requirements to properly care for PPG:  Protective grounding equipment shall be kept clean and stored in the truck bin or in bags.  Protective grounding equipment shall be tested for resistance every year. 5.11 Clean Connections The surface to which the ground equipment is to be attached shall be cleaned before the grounding clamp is installed.  Wire brushes on hot sticks can be used to clean conductors. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 15 of 50

6 PERSONAL PROTECTIVE GROUNDING OF OVERHEAD DISTRIBUTION LINES AND DEVICES Figure 1 — PPG of Overhead Distribution Lines and Devices When work requires distribution lines and equipment to be de-energized and grounded, a PPG procedure that creates an EPZ shall be developed at the worksite. To develop an EPZ follow the steps below: 1. Obtain authorization from the control center to de-energize the line (clearance/terminal clearance) or establish a personal clearance. 2. Conduct a tailboard and develop grounding plan. 3. Identify the best available worksite ground source (in most cases the common neutral). 4. Test the lines and equipment using an approved and tested voltage detector. 5. On wood, concrete or fiberglass structures, install a cluster bar, below the work position. On steel structures, locate the grounding point or install a tower grounding clamp. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 16 of 50

6. Install a proper length and sized protective grounding jumper (see protective grounding equipment) between the cluster bar and the identified ground source (the common neutral). 7. Install a proper length and sized protective grounding jumper on the cluster bar or ground source, and, using an approved live line tool, attach the other end to the closest phase conductor. 8. Install a proper length and sized protective grounding jumper on the grounded conductor, and using an approved live line tool, attach the other end to the next closest phase conductor. 9. Install a proper length and sized protective grounding jumper on the grounded conductor, and using an approved live line tool, attach the other end to the last ungrounded phase conductor. 10. Ensure all structures, lines, equipment and ground sources within the worksite are bonded together with protective grounding jumpers and equipment. 11. Ensure the worker(s) are within the EPZ before, and while in contact, with any grounded conductor or equipment. 6.1 PPG Away From the Work Location 1. Obtain authorization from the control center to de-energize the line (clearance/terminal clearance) or establish a personal clearance. 2. Conduct a tailboard. 3. Identify the best available worksite ground source (in most cases the common neutral). 4. Test the lines and equipment using an approved and tested voltage detector. 5. Install tripping grounds within one span of the worksite by installing a properly sized grounding jumper from the neutral to the closest phase conductor using hot line tools. Then jumper the other phases together working from the nearest to the farthest distance. 6. On wood, concrete or fiberglass structures, clean all grounding contact surfaces (e.g. clamp, conductors and cluster bar). Install a cluster bar on the pole, below the work position. Using a proper length and sized protective ground, attach ground clamp to cluster bar then connect ground to the best identified ground source (the common neutral). 7. For steel structures, locate the grounding point or install a tower grounding clamp. Clean all grounding contact surfaces (e.g. clamp, conductors and cluster bar). Install a cluster bar on the pole, below the work position. Using a proper length and sized protective ground, install ground clamp to cluster bar then connect ground to the best identified ground source (the common neutral). 8. After the work is completed, remove PPG in reverse order. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 17 of 50

6.2 PPG When Distribution Conductors Are Down or Broken and On the Ground Figure 2 — PPG for Downed or Broken Distribution Conductors on the Ground If overhead conductors have been moved from their normal position and are down or lying on the ground, the following PPG procedure shall be followed: 1. Obtain authorization from the control center to de-energize the line (clearance/terminal clearance) or establish a personal clearance. 2. Conduct a tailboard. 3. Identify the best available worksite ground source (in most cases the common neutral). 4. Test the lines and equipment using an approved and tested voltage detector. 5. If the conductors are down, but not broken, install PPG on one side of the worksite. If the conductors are broken, install PPG on both sides of the break where the conductors would be in their normal position. 6. All workers shall wear high-voltage rated gloves, or create an EPZ by connecting ground mats to the conductor. (Note: Never become in series with open conductors even when wearing high-voltage rated gloves.) 7. Splice the conductor(s) together and re-install them in their normal position. Once the conductors are off the ground and cannot be contacted by workers on the ground, high-voltage rated gloves can be removed. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 18 of 50

8. After the work is completed, remove PPG in reverse order. 6.3 Splicing or Opening Distribution Conductors When working on a grounded conductor at a deadend structure, where jumpers are open, or will be opened, the ungrounded conductor(s) shall be grounded. Use temporary grounding jumpers installed from the EPZ bar or from the previously grounded conductor to the remaining other conductors and across the permanent line jumpers prior to opening or cutting open the permanent line jumpers. After the work is completed, these connections are removed in reverse order. When working on a grounded conductor at a deadend structure, where jumpers are, or will be opened, the ungrounded conductor(s) shall be covered with insulated barrier(s) rated for the voltage being worked, or a temporary grounding jumper shall be installed from the grounded conductor across the open deadend. When a splice is installed or removed on a conductor, a protective grounding jumper shall be installed from the ground source to the de-energized conductor, and a second protective grounding jumper shall be installed across the splice. 6.4 Working with De-Energized Distribution Conductors at Ground Level Before lowering a de-energized distribution conductor, a protective grounding jumper shall be installed on the conductor before it is disconnected from the insulator, and the conductor shall remain grounded until it is re-installed on the insulator. When a grounded conductor is brought to the ground, and before workers on the ground contact the grounded conductor they shall:  Don high-voltage rated gloves, or  Stand on rated insulated mats, or  Create an EPZ by connecting ground mats to the conductor, or  Create an EPZ by standing on a truck or trailer’s metal deck using lug or pad installed for this purpose, connected to the conductor. The area where the grounded conductor will be brought to earth, which is not protected by the options above, shall be roped off. A fiberglass platform or an insulated mat shall be laid at the access to the roped area. 6.5 Grounding Overhead Distribution Capacitors 1. Before work is done on switched or fixed capacitor installations, open the circuit to the capacitor through a circuit breaker or other device provided for that purpose. If opening the capacitor bank through cutouts, use portable load break tools for switching applications that are within the ratings of the tool selected. 2. Capacitors shall be considered energized at full line potential until they have been disconnected from the line and their terminals short circuited and discharged to ground. 3. After disconnecting the capacitors from the voltage source, wait at least five minutes before grounding to allow for bleed-off of residual charge. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 19 of 50

4. Using a hot stick, apply a ground wire to each terminal of each capacitor. Short- circuit and ground the terminal bushings of the capacitors. 5. Shunt the capacitor (using high-voltage rated gloves) before attempting to work on or remove it. Use, (at a minimum) six-gauge solid copper wire for the shunt. Insert the shunt into the bushings, tighten and securely bond to the cases. Perform this work wearing high-voltage rated gloves. 6. When capacitors are in storage, all bushings on the unit shall be shorted together. 7 TRANSMISSION GROUNDING PROCEDURE 7.1 Clearance/Terminal Clearance No work on a de-energized transmission line shall be started until a clearance has been issued from the region system/grid operator and the line has been verified de-energized, properly tested and grounded. Note: A terminal clearance may be issued instead of a clearance on a subtransmission line below 100 kV in very limited situations, such as when an isolation switch is very remote and is not accessible. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 20 of 50

7.2 PPG of Overhead Transmission Lines and Devices Figure 3 — PPG of Overhead Transmission Lines and Devices (Example: H-frame transmission structure, with static wires. An equipotential zone has been established from the cluster bar to the top of the pole.) When grounding transmission lines with bundled conductors, the subconductors shall be bonded together at the trip ground location. The hardware shall not be relied on for this bond. If a multi-grounded shield wire is available, it is typically the best available ground source. If bracket grounding is used, all three phases shall be grounded at each end of the work zone. All transmission conductors, cables and equipment should be considered to have dangerous levels of electric field induction until they have been tested and found safe, or proper work methods detailed in this procedure are used to eliminate the electric field induction hazard. Refer to Appendix A for more information on induction hazards. 1. Obtain a clearance from the control center. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 21 of 50

2. Use approved testing devices to ensure the line is de-energized. 3. Clean the connections on the conductor and the grounds. 4. Use an approved hot stick and make the grounding connections in the following order: a) Install a ground jumper from the static to the closest phase conductor. b) Install a ground jumper from the grounded phase conductor to the next closest phase conductor. c) Install a ground jumper from the two grounded phase conductors to the last phase conductor. d) If a second static is present, include the second static into the bonded conductors. 5. Keep jumpers taut; minimize slack. 6. Install a cluster bar on the pole/s just below the work area to create the EPZ. 7. For one, two or more poles, bring a grounding jumper to each cluster bar. 8. Remove the grounds in reverse order. Where the planned work involves only one-phase and the MAD can be maintained from the other two phases, a PPG procedure, developing an EPZ at the worksite, may be constructed on the phase to be worked. Approval from the safety department required. There may be some instances where the safety department may not be able to assist e.g. remote work, communication system failure, etc. The crew foreman in charge may authorize the crew to proceed as outlined in both the APM and Grounding Manual. Upon return the crew must do the following: o Contact the safety department and inform them of work practices taken place o Provide a copy of the crew’s tailboard and grounding plan for that work location 7.3 Grounding for Transmission Lines with Distribution Underbuild Follow these steps to apply PPG to transmission lines with distribution underbuild: 1. Obtain a clearance from the control center. 2. Use approved testing devices to ensure the line is de-energized. 3. Install a cluster bar on the pole just below the work area. 4. Clean the connections on the conductor and the grounds. 5. Use an approved hot stick and make the grounding connections in the following order: a) Install a ground jumper from the system neutral to the cluster bar. b) Jumper the cluster bar to the closest phase conductor. Jumper the other phases together working from the nearest to the farthest away. 6. Keep jumpers taut; minimize slack. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 22 of 50

7. If a static wire is present, jumper the bonded conductors to the static wire. Bond neutral to static (both) two pole. 8. Remove the grounds in reverse order. Figure 4 — PPG for Transmission Lines with Distribution Underbuild (Example: Y-frame transmission structure, with static wire and energized distribution below. An equipotential zone has been established from the cluster bar to the top of the pole.) 7.4 Series Capacitors and Shunt Reactors When series capacitors and/or shunt reactors are connected to transmission lines and equipment, the region system/grid operator shall isolate the equipment before issuing a clearance involving de-energizing and grounding transmission lines and equipment. 7.5 Shield Wires and OPGW Much of Rocky Mountain Power’s transmission system is built with grounded shield wires/OPGW. These shield wires are grounded at each structure, and should be used as a source ground for PPG. Ensure the grounded shield wires are bonded with protective grounding jumpers into the EPZ. OPGW shall be grounded in the same manner as static shield wires using a torque wrench set to 250 inch-pounds. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 23 of 50

The OPGW grounding policy is found on Safety’s webpage. Protective Grounding on OPGW document. http://idoc.pacificorp.us/safety_and_occupational_health/rmphs.html 7.6 Steel Structures If the structure is steel: 1. Steel poles may have some form of coating such as a weathering steel, galvanizing, paint or rust. If you are bonding to a coated area make sure the grounding clamp penetrates the coating or the coating is removed. 2. Install a correct tower clamp with a serrated jaw on the steel below the working position, or install grounding studs as necessary (galvanized bolts must be excluded/ruled out in advance). 3. Clean all electrical connections. Clamp one end of a properly sized and correct length grounding jumper to the tower clamp and the other end to the approved ground source, as specified above. 4. Install a properly sized grounding jumper of correct length from the tower clamp, or ground, to the closest phase conductor using hot line tools. 5. Jumper the other phases together working from the nearest to the farthest away. 6. After the work is completed, remove PPG equipment in reverse order. If the structure is tubular steel: 1. Install a grounding stud at a location specified by the manufacturer of the structure. 2. If no stud location is specified, contact the safety department. 3. Clamp one end of a properly sized grounding jumper of correct length to the grounding bolt and the other end to the approved ground source, as specified above. 4. Install a properly sized grounding jumper of correct length from the grounding bolt, or ground, to the closest phase conductor using hot line tools. 5. Jumper the other phases together working from the nearest to the farthest away. 6. After the work is completed, remove PPG equipment in reverse order. 7.7 Aerial Splicing or Opening Transmission Conductors When a splice is installed or removed on an existing transmission conductor, a protective grounding jumper shall be installed from the ground source to the de- energized conductor, and a second protective grounding jumper shall be installed across the splice. Use single point or bracket grounding method and place as close as possible to the work location. If working on a pole or structure from an aerial device, the following grounds are required: 1. Use the single point or bracket grounding method at the work location. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 24 of 50

2. If workers are closer to the conductor than the minimum approach distance, a cluster bar and ground shall be installed and connected to the conductors being reached. 3. If workers are closer to a steel structure (or an engineered tubular tower with grounding locations) than the minimum approach distance, they shall install a ground from the steel structure to the conductor being worked on or other conductors within reach. 7.8 Working with De-Energized Transmission Conductors at Ground Level Figure 5 — PPG for De-Energized Transmission Conductors at Ground Level Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 25 of 50

Before lowering a de-energized transmission conductor, a protective grounding jumper shall be installed on the conductor before it is disconnected from the insulator, and protective grounding jumper shall remain grounded until it is re-installed at the insulator. The area where the grounded conductor will be brought to earth shall be barricaded off if possible. A fiberglass platform or insulated mat shall be laid at the access to the EPZ area. When a grounded conductor is brought to the ground, and before workers on the ground contact the grounded conductor they shall:  Don high-voltage rated, or  Create an EPZ by connecting ground mats to the conductor, or  Create an EPZ by standing on a truck or trailer’s metal deck using a lug or pad installed for this purpose, connected to the conductor. 7.9 Ground Switches Ground switches have been installed for many years on both terminals of some transmission lines. Studies have shown that magnetic field induction between parallel transmission lines can be hazardous due to the induced voltage and current. Having more than one ground source on a line may result in a hazardous condition known as circulating current. If there is a problem installing or removing grounds at the worksite because of induced currents and voltage, one ground switch should be closed, during the installation or removal transition. Before closing a ground switch, the line should be tested and verified to be de-energized with an approved and tested voltage detection device. 7.10 Determining Step and Touch Potential Electric and magnetic field induction can create hazardous step and touch potentials at the base of transmission structures when lines and equipment are grounded. To determine the step and touch potential levels with protective grounds installed do the following procedure: 1. Drive a 3/8-inch to 5/8-inch diameter metallic probe approximately 15 feet from the base of the structure to a depth of 18 to 24 inches. 2. Don high-voltage rated gloves and protectors. 3. Connect multi-meter lead to metallic probe. 4. Set multi-meter to highest AC voltage range. 5. Connect other lead of the multi-meter to tower leg. 6. Follow the appropriate steps above to ground the line. 7. Take voltage measurements by lowing the multi-meter’s AC voltage range until a voltage is measured. Voltage measurements under 50 Volts: Work may proceed normally without extra protective measures. Ground workers may wear high-voltage rated gloves and protectors to avoid minor shocks. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 26 of 50

Voltages measurements between 50 and 500 Volts: All ground workers may be exposed to hazardous step and touch potential, and shall wear high-voltage rated gloves with protectors, and insulated overshoes. Ensure no uninsulated body parts contact structure. Voltages measurements over 500 Volts: After all practical efforts have been made to reduce the voltage to its lowest level, remove the protective grounds and follow normal hot line procedures. For tasks where hot line techniques are not practical, approved alternative methods should be considered for accomplishing the work. 7.11 Reducing Step and Touch Potentials Step and touch potentials can be reduced in several ways: 1. Open ground switches at the line terminals. 2. Ensure there is a very low ground resistance connection to the grounded shield wire(s). 3. Install a set of tripping grounds one span from the worksite. 4. Reduce the length of the line by opening disconnects or jumpers. 7.12 Multiple Crews Working the Same Transmission Line Where Induced Currents and Voltages are Present to Parallel Transmission Lines When multiple crews work on a de-energized and grounded transmission line, hazards can be developed from the multiple ground locations. When the hazards of induced currents and voltages are present due to the proximity of other energized transmission lines running in parallel with the transmission line to be worked on, one of the following grounding procedures shall be followed: 1. Crews shall progress forward (leapfrog) from one structure to the next; each crew working on alternate structures. Grounds shall be applied at each structure and an EPZ shall be created. 2. Crews shall work within a three- to four-mile distance of each other. a) One master set of grounds shall be applied to the transmission line within that three- to four-mile mile distance and shall be available. b) Each crew at their specific work location will then create an EPZ on the pole by installing a cluster bar and installing a ground cable from the conductor being worked on. 7.13 Multiple Crews Working on the Same Transmission Line Where No Induced Currents and Voltages are Present 1. Each crew at their specific work location shall install a set of grounds and create an EPZ using the cluster bar. The grounds shall be tied into the best ground source available. 2. Crews will still be allowed to work two spans away from the grounded structure in either direction, but will still be required to create an EPZ on the pole they are working on by installing the cluster bar (where applicable) and installing a ground cable from the cluster bar to the conductor being worked on. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 27 of 50

3. When work proceeds to more than two spans away from the grounds, the crew shall transfer the existing set of grounds to their new work location and proceed as outlined. 8 UNDERGROUND GROUNDING PROCEDURES Figure 6 — PPG for Underground Systems 8.1 Grounding Insulated Power Cable Employees working on underground systems can be protected by the insulation, isolation and grounded EPZ methods. Each has its advantages and disadvantages, depending on the construction of the underground system. Refer to Appendix B for more details about these methods. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 28 of 50

Protection for workers on underground systems is much more difficult because of the compactness of the equipment, the location of the work and the difficulty defining safe work procedures in this environment. However, the same methods of protection apply: insulation, isolation or grounded EPZ. They can be more difficult to implement. For example, when a system fault occurs while one cable is de-energized and grounded to the system neutral, a transfer of potential is possible through the cable conductor and the system neutral to a work location. The transfer of this potential through the cable and concentric neutral conductors results in a potentially hazardous voltage difference along the length of the cable and between the cable and earth. If protective grounding is inadequate or improperly applied, workers contacting the cable, concentric neutral or device connected to the cable, could be subjected to hazardous potential differences. The insulation method can be used any time after the cable has been de-energized, a clearance has been issued or established, and the cable has been properly grounded. It consists of using rated insulated tools or high-voltage rated gloves to handle the cable system. CAUTION: Most insulated power cable is constructed in a similar manner as a high voltage capacitor. Care must be taken with de-energized and isolated cable as it will still hold a trapped charge (as will a capacitor) until it is properly drained. Cable testing (DC Hi-potting) can impress a trapped DC charge onto a previously de-energized and grounded cable. Previously tested, de-energized and grounded cable can also have a charge induced onto it from adjacent overhead or underground lines or equipment fields. Worksite protective grounding for insulated power cable terminations shall be accomplished similar to that required for grounding on power line structures. If possible the cable phase conductor terminals (terminators, potheads, etc.) and shield conductors shall be bonded to the worksite grounding system. The entire cable shall be treated as if it is energized until it is also isolated, tested and grounded. In energized environments, the cable pulling equipment and cable reel unit shall be grounded to the best available ground source. Equipotential mats, large enough for the movement involved, will be used whenever any crew member must be in contact with any piece of equipment. More than one equipotential mat can be bonded together to cover large areas. This can be accomplished by connecting a grounding jumper to each mat bonding lead (see Figure 7). Figure 7 — Equipotential Mat and Grounding Jumper Connection Equipment operators shall stand on an insulated platform or equipotential mat that is bonded to the equipment when operating the cable-puller or working at the reel dolly or cable reel truck to protect those employees from different electrical potentials in case of Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 29 of 50

an accidental energizing of the cable. Insulated mats or some other insulated method can allow for movement of men and materials in or out of the EPZ. PPG and EPZ Method (Equipotential, preferred method) is better suited for use at connection points, switches, transformers, etc., because a worker is standing on the earth and handling parts that may become energized, an EPZ should be established. It can be established by bonding a conductive mat to all conductive elements in the worksite that could potentially be contacted. Insulation Method use high-voltage rated gloves and insulated mats at connection points, such as switches or transformers. The compactness of the enclosed equipment often makes high-voltage rated glove or hot stick work difficult. Isolation Method is the method of keeping the worker away from any situation that would allow contact with any possible source voltage. This alternative totally isolates equipment from any power source. This may not be practical for maintenance of existing installed equipment because every connection (including grounds and concentric neutrals) must be removed and isolated. Like the insulation method, isolation in compact, enclosed spaces often makes rubber glove or hot stick work difficult. This method is primarily used for work on buried cables between connection points where creating an EPZ including the phase conductor is difficult. 8.2 Underground Cable Splicing and Adding Terminations The EPZ method is suitable for some tasks that occur between connection points, but is not suitable for others. Adding a switch or transformer between existing switches or transformers requires digging, cutting and the installing of equipment. 1. The cables are first de-energized, tested and grounded, and then exposed by digging. 2. Use hot line tools to isolate or ground the cable on both ends. 3. If the cable is bare concentric or the concentric is exposed, an EPZ can be created at the worksite. A hot cutter is used to verify that no voltage remains on the conductor about to be cut. Care should be taken in choosing the location to cut the cable, because the test location must be reinsulated after the work is completed and before the site is re-energized. The test site is usually removed so that a splice or termination can be installed. A temporary connection of sufficient capacity shall be made between the concentric neutrals of the two open ends to maintain continuity as it functions as part of a system neutral. Because of the neutral current touch potential hazards that exist, isolation or insulation methods shall be used until an EPZ can be established. A conductive ground mat to work from, can then be bonded to the concentric neutrals. The phase conductors however cannot be bonded locally in the worksite until they are exposed, at which point the terminations are usually immediately affixed. This leads to the need to use isolation methods on the phase conductor while it is being worked on. Note: An EPZ is created by bonding together all conductors that a worker may come in contact with. Only after the complete EPZ is created can isolation or insulation methods be stopped. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 30 of 50

After the cable is identified and tested de-energized, two of the three methods may be used together. Insulation is the most common method combined with grounded EPZ or isolation methods. For example, the cable’s concentric neutral may require use of the insulation method until an EPZ can be established. While using isolation method, if the concentric neutrals are not isolated correctly at the cable termination locations neutral currents and fault currents can flow creating step and touch potential hazards at the worksite. Therefore insulation must be used while the EPZ to the concentric and isolation to the phase conductor are established. While it is recommended to establish an EPZ between all the conductors inside a worksite an EPZ is sometimes impractical while installing new URD terminations of any type hence this combination of insulation and isolation methods is required. The combination of protection methods described above is only allowed after the cable is identified, isolated and grounded then tested de-energized. 8.3 Bare Concentric Cables The difficulty of isolating a bare concentric cable is that the current can flow directly from the distribution system’s earth grounds through soil to the bare concentric cable that is being worked on. Complete isolation of any bare concentric neutral cable is impractical. Creating an EPZ at the work location using a ground mat to the bare concentric cable should be achieved immediately after the cable is identified, isolated, grounded then tested de-energized. After the use of the hot cutter tool and before an EPZ is established between the neutrals, a hazard is created by the possibility of getting in series between the two cut ends of the cable. If the EPZ method is used, neither the worker nor the portable ground mat should be in series with the neutral or fault current path. If the cable becomes energized the worker is in parallel but will experience very little current flow across their body. The vast majority of the current will flow along the grounding jumpers low resistance path, creating a very low voltage drop across the worker inside the EPZ. The use of an insulated method shall be required during the initial work of isolating the neutral conductor and ground connections. An insulated method shall be used again during this closing work to remove the EPZ connections, grounds and to reconnect any previously isolated grounds and neutral conductors. 8.4 Working URD Cable Using the Isolation Method Steps for Isolation Method: 1. Identify the cable. 2. Obtain authorization from the control center. 3. Find visible openings on both ends of the cable and de-energize. This can be achieved by moving the loadbreak elbow to a parking bushing, opening a switch. 4. Tag open points with a Do Not Operate tag. 5. Obtain a clearance (from region system/grid operator or establish a personal clearance). Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 31 of 50

6. Use an approved and tested voltage detector to ensure the cable is de-energized by testing both ends of the cable. 7. Using an approved grounding elbow, ground both ends of the cable. 8. If the cable being worked on is a dedicated line serving three-phase loads ground all three phases. 9. Wait one minute to bleed off any capacitive charge left on the cable and then remove both grounding elbows, leaving the cable’s phase conductor ungrounded and isolated on the stand-off bushings. 10. With high-voltage rated gloves on, disconnect the cable’s concentric neutral from the system neutral. Ensure the concentric neutral is completely isolated on both ends. (Complete isolation of bare concentric neutral cable is not practical; see EPZ and Isolation Method.) CAUTION: When opening a cable’s concentric neutral do not place yourself in series with the concentric neutral. 11. If the cable is to be cut, do so with hot cutters. 12. Proceed with the planned work on the cable system. 13. When the work is finished, reconnect both ends of the cable’s concentric neutral using high-voltage rated gloves. 14. Release the clearance on the cable and remove the clearance tags from the elbows. 8.5 PPG of URD Cable Using the EPZ and Isolation Method EPZ and Isolation Method: 1. Identify the cable. 2. Obtain authorization from the control center. 3. Find visible openings on both ends of the cable and de-energize, this can be achieved by moving the loadbreak elbow to a parking bushing, opening a switch. 4. Tag open points with Do Not Operate tag. 5. Obtain a clearance (from region system/grid operator or personal). 6. Using an approved and tested voltage detector, test the cable to determine it is de- energized at both ends of the cable. 7. Using an approved grounding bushing or approved grounding jumper, ground both ends of the cable. 8. If the cable being worked on is a dedicated line serving three-phase loads ground all three phases. 9. Wait one minute to bleed off any capacitive charge left on the cable and then remove the grounding bushing, leaving the cable’s phase conductor ungrounded on a parking bushing, but isolated. If the cable’s concentric neutral is intact and in good condition throughout the entire length of the cable, the cable may be grounded using the grounding bushing. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 32 of 50

10. At the work location, lay a ground mat where workers can stand when working on the cable. Connect ground mat to the cable’s concentric neutral using a bonding jumper. If the cable is jacketed, using high-voltage rated gloves cut off the jacket and install the bonding jumper to the cable’s concentric. 11. If the cable is to be cut install a concentric bonding jumper across the point of the cable to be opened before cutting. When possible installing this bonding jumper prior to cutting reduces the risk of getting in series with the two ends of the cable. 12. Cut the cable with hot cutters. 13. Proceed with planned work on the cable or elbow. 14. Using high-voltage rated gloves reconnect any neutral connections that may have been opened for isolation. Once nuetral connections have been reconnected disconnect the EPZ. 15. When the work is finished, release the clearance on the cable and remove the clearance tags from the terminations. 8.6 Opening the Concentric Neutral When work requires a grounded cable’s concentric neutral to be opened, and the cable isolation work method is not used, a concentric neutral bonding jumper shall be installed on the concentric neutral across the point of the cable to be opened, prior to cutting the concentric neutral. If the EPZ is not practical or would create an unsafe condition, a concentric neutral bonding jumper need not be installed, but the line or equipment must be worked using the insulation method. 8.7 PPG of Cable Using the Insulation Method The insulation method places a barrier between the worker and the de-energized conductor by means of approved live line tools or appropriate high-voltage rated gloves. The use of live­line tools requires no special grounding of the conductor after it has been proven de-energized by isolation, test de-energized and the ground method. The use of insulated barriers and covers should be used in combination with high- voltage rated gloves to mitigate the risk of accidental contact with other sources of potential. While using high-voltage rated gloves or hot tools, an EPZ still shall be set up at the work location, using an equipotential mat, to keep the worker at the same potential as the grounded neutral and equipment such as ground sleeves etc. When a deadbreak connection (which includes deadbreak elbows) must be separated, it first requires spiking or remote cable cutting of the connection. If no other means of grounding are available, high-voltage rated gloves can be used to separate these connectors or to perform the work. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 33 of 50

8.8 Isolation Method for Cable Replacement in Existing Equipment Ensure that proper insulated barriers are used. Create an EPZ at the worksites at both ends of the cable. When work is to be done on an isolated conductor, such as cable replacement, maintain the isolation of that conductor until all crews working on that cable are ready to bond the cable to the EPZ that may extend to the existing equipment and or cables. All work being performed on the cable will have the neutral opened last and closed first. If space restrictions do not allow permanent connections, jumper out the wires until the permanent connection can be made. Once the neutrals are bonded together, the insulation method (high-voltage rated gloves) must be used to reassemble the connectors. When more than one crew is working a job, proper communications must be maintained to ensure all crews are working that portion of cable using the same approved method when handling the cable. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 34 of 50

8.9 Methods of Grounding High-Voltage Cable Figure 8 — PPG for High-Voltage Cable The grounding elbow, when used with a feed-through bushing, provides a positive method of grounding 200-amp cables. The grounding elbow may also be used to ground 200-amp loadbreak equipment prior to work being performed. Live line tool application is required. The parking bushing offers a point of isolation at that loadbreak connection. The feed- through bushing, when used with a grounding elbow, provides a positive method for grounding loadbreak elbows. This requires a live line hot stick application. With pad-mounted, live-front equipment, cluster grounds can provide a positive grounding capability to three-phase live-front equipment. The cluster ground is Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 35 of 50

equipped with three clamps designed to grip onto the cable lug, with small copper conductor, or bus assembly and a single grounding clamp for the equipment ground bus wire. 8.10 Fault Finding Impulse tests and proof testing cables require the conductor to be placed under a test voltage. Before any impulse generating equipment can be connected to the conductor, the cable run must be identified, isolated, tested de-energized and grounded. The If a second static is present, include the second static into the bonded conductors of hot line tools is required to connect and disconnect jumpers between the testing unit and local equipment. Temporary PPG may only be removed from the conductors during the time a test voltage is applied. CAUTION: The conductor under test must be treated as energized until it is grounded. 1. Identify the cable. 2. Obtain authorization from the control center. 3. Find visible openings on both ends of the cable and de-energize. This can be achieved by moving the loadbreak elbow to a parking bushing, opening a switch or pulling a fuse. 4. Tag open points with Do Not Operate tag. 5. Create a personal clearance. 6. Use an approved voltage detector to ensure the cable is de-energized by testing both ends of the cable. 7. Using an approved grounding elbow, ground both ends of the cable. 8. If the cable being worked on is a dedicated line serving three-phase loads, ground all three phases. 9. Wait one minute to bleed off any capacitive charge left on the cable and then remove both grounding elbows, leaving the cable’s phase conductor ungrounded and isolated on the stand-off bushings. 10. Proceed with planned work on the cable system. 11. Release the personal clearance by removing Do Not Operate tags and, as required, the follow-up crew will need to establish their own personal clearance. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 36 of 50

9 SUBSTATION AND SWITCHYARD GROUNDING PROCEDURES 9.1 Policy This section established the policy to be followed in all substations and switchyards to assure consistency in ordering and using protective grounding equipment. The primary reason is to guarantee that all workers are adequately protected by the protective grounding equipment being used. Where lines terminate in substations, they shall be treated in accordance with the applicable transmission and distribution sections of this manual. 9.2 Clearance/Terminal Clearance If a clearance/terminal clearance is required before beginning any work on a de- energized line or circuit, obtain a clearance/terminal clearance from the region system/grid operator. A clearance is issued assuring that the line or circuit is open and has been de-energized or isolated either from all known sources of energy and that all known potential sources have been tagged. A terminal clearance is issued when a terminal has been de-energized and tagged out at visual open points at the normal sources. 9.3 Specifications 4/0 copper or parallel 2/0 copper grounds shall be used in substations or switchyards. Single lead grounds or cluster type grounds are acceptable. Single 4/0 copper grounds or parallel 2/0 copper grounds shall be used when available fault duty is 40 kA and below. Above 40 kA, parallel 4/0 copper grounds shall be used. All PPG shall be electrically tested with an approved testing device at least annually. PPG shall be kept clean and in good condition and should be stored in the truck bin or in bags. 9.4 Grounding Practices The following established safe grounding practices will help to assure personal protection: 1. When paralleling grounds, they must be of equivalent length. 2. Only grounding cables and clamps approved by the safety department and ASTM (ASTM Grade 5 clamps, ferrules and assemblies. AWG: 4/0 Cu. ASTM Grade 4 clamp, ferrules and assemblies. AWG: 2/0 Cu) and specified in company standards shall be used for personal protection (4/0 in substations; line crews can use parallel grounds). 3. Clean bus and conductor where grounds are to be applied. (Clean and tight connections help assure the best electrical connection.) 4. All grounding clamps shall be installed and/or removed from primary conductors with an approved hot stick. Proper safety procedures will be observed. 5. Apply personal ground to ground grid, then conductor, bus, apparatus or other piece of equipment. Verify that clamps are tight. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 37 of 50

Note: Care should be taken to minimize cable slack. Do not coil the excess cable slack or length. Tie excess cable slack or length back with a rope. 6. Single-point grounding and chain grounding are acceptable when available fault duty is below 40 kA. Single-point grounding is required above 40 kA. 7. Grounds should be applied as close to the work area as possible. 8. Installation accessories, such as “shepherds hook” assemblies are available and aid in applying the grounds in cases where a long lift is required, e.g., where reach distance, direction, size, length, and weight of protective equipment are unwieldy. 9. Grounds should not be applied to corona rings, armor rod, line dampeners or welded on aluminum grounding studs. 10. Grounding shall not be through a circuit breaker, circuit switcher, series reactor or fuse. In many cases, the standard leads will be longer than required for some jobs. Therefore, it is imperative that the excess lead be secured by whatever means necessary. Installation accessories, such as \"shepherd's hook” assemblies are available and aid in applying the grounds in cases where a long lift is required. 9.5 Special Grounding Situations 1. Where equipment such as series reactors, line traps, CTs or other similar equipment connected in series with the line are removed or disconnected, electrical continuity shall be maintained across the open with jumpers or additional grounds. 2. Series capacitors, energy storage sites, static VAR compensators and STATCOMs: These devices are unique and require specific grounding plans for each device. A grounding plan can be found at the site. Questions should be directed to the safety department and substation operations. 3. Fused and fuseless shunt capacitor banks: a) After isolating the capacitor bank per region system/grid operator switching orders, wait five minutes before grounding to allow for bleed-off of residual charge. b) Apply personal grounds around the entire capacitor bank. c) Touch ground each individual level of the capacitor bank, starting at the lowest level and moving upwards to the top level of the capacitor bank. d) Using an approved insulated hot stick, remove any bird protection covers and momentarily short each can with a #6 solid copper wire within a 5-foot radius of the work area. Any sparking indicates residual charge was left in the capacitor tank. e) Wearing high-voltage rated gloves, shunt all bushings and the capacitor tank case by bolted connections using a #6 solid copper wire on all tanks that are to be worked on or removed. Note: Any capacitor tank not installed shall have a shunt applied (All bushings shunted and connected to the case by bolted connections using #6 solid copper.) Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 38 of 50

9.6 Testing When certain tests are performed on substation equipment that require the removal of one or both sets of grounds, the grounding procedures shall be followed prior to testing. These tests include ductoring, meggering, sequence indicating, Doble testing, current transformer polarity tests or any other test that requires an individual to work in an area capable of becoming energized at over 600 volts. When Doble testing power transformers: 1. De-energize and test de-energized high- and low-side bushings of the transformer. 2. Apply personal grounds to both sides of the transformer until transformer testing is complete. 3. Remove bus and or conductor from the high - and low-side bushings. 4. Testing of the transformer can proceed without personal grounds. 5. After running Doble test, touch ground bushings bleeding any residual charge from transformer, test leads can then be moved for further testing of the transformer. Bagging of open, three-phase, vertical, gang-operated airbreak switches on circuit breakers will be left up to individual crews through the tailboard process. Bagging is a process of assuring that a vertical switchblade cannot fall into a closed position. Any circuit breaker using primary voltage to close the circuit breaker needs to be closed with the maintenance handle provided for this purpose. Follow appropriate dispatch switching orders, which include removing all tags and returning the clearance and closing appropriate disconnect switches. After tests have been completed, switching orders shall be followed to open the disconnect switches and clearance shall be returned and disconnects shall be tagged. If the equipment to be tested is connected to a line section, the equipment under test shall be isolated from the line (and the line shall remain grounded) or the test shall be conducted with the grounds in place. Once testing has been completed, any grounds removed shall be replaced before work continues. CAUTION: Test leads shall be connected to the test equipment first and disconnected from the test equipment last. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 39 of 50

10 MECHANICAL GROUNDING EQUIPMENT 10.1 Electrical Protection Working with Insulated Booms During the tailboard, such factors as the task to be performed; the length of the boom; stability of the ground supporting the equipment; wind and other weather conditions; skill of the operator; responsiveness of the mechanical equipment's controls; and the type of winch line, wire or rope shall be considered when determining if additional distance should be added to the MAD. When utility vehicles are operated between 10 feet and the MAD, each employee shall be protected from the hazards that might arise from accidental equipment contact with the exposed energized lines and equipment by the use of at least one of following: 1. The exposed energized lines and equipment exposed to contact shall be covered with rated insulating protective material capable of withstanding any energized contact during operation. Adequate insulating protective material shall be installed so that the mechanical equipment does not enter the MAD. a. Temporary insulating platforms shall be installed at points where employees will contact the equipment. b. The mechanical equipment shall be barricaded to prevent employees from contacting the equipment. 2. The equipment shall be insulated for the voltage involved. The uninsulated portions of the mechanical equipment shall not approach the exposed energized lines and equipment any closer than the MAD. a. Temporary insulating platforms shall be installed at points where employee will contact the equipment. b. The mechanical equipment shall be barricaded to prevent employees from contacting the equipment. 3. The mechanical equipment shall be barricaded to prevent employees from contacting the equipment. Workers on the ground shall not come in contact with equipment until: a) The mechanical equipment’s boom, and load, has been moved 10 feet outside of the MAD, and b) The mechanical equipment shall remain 10 feet outside of the MAD until the worker(s) communicate that they are outside of the barricade. 4. Preferred method in substation areas: The equipment shall be grounded to the best available ground source, as specified in Table 1, to minimize the time exposed energized lines and equipment remain energized, and at least one of the following practices shall be used: a) Temporary insulating platforms, temporary ground mats bonded to the equipment chassis shall be installed at points where employees will contact the equipment. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 40 of 50

b) Employees shall use protective equipment, such as high-voltage rated gloves, or transition mat to protect from touch potentials around the mechanical equipment. c) The mechanical equipment shall be barricaded to prevent employees from contacting the equipment. Workers on the ground shall not come into contact with equipment until: i. the mechanical equipment’s boom, and load, has been moved 10 feet outside of the MAD, and ii. the mechanical equipment shall remain 10 feet outside of the MAD until the worker(s) communicate that they are outside of the barricade. When any two or more pieces of mechanical equipment at a worksite, having a boom near exposed energized lines and equipment, are positioned in a way that allows workers to contact both vehicles, both shall be bonded together to minimize potential differences. Where the general public might contact mechanical equipment operating near energized lines and devices, barricade tape should be used to warn the public of potential hazards. 10.2 Electrical Protection Working with Noninsulated Booms When work on de-energized lines and equipment is performed out of a noninsulated aerial platform, a PPG procedure, detailed above in note 4, Section 10.1, shall be first completed. The noninsulated aerial platform shall be barricaded or conductive mats arranged around the equipment ensuring no worker can contact the equipment when it is bonded to the de-energized lines and equipment. An approved bonding jumper shall be connected to the ground point on the platform. The other end of the bonding jumper shall be installed on the de-energized and grounded conductor using rated live line tools. When work is complete, the bond shall be removed from the de-energized and grounded conductor with rated live line tools. Workers in the platform shall not physically contact the de-energized line or equipment unless the platform is bonded to the de-energized and grounded conductor. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 41 of 50

Figure 9 — PPG for Noninsulated Booms Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 42 of 50

11 GROUNDING DURING STRINGING OPERATIONS Figure 10 — PPG for Stringing Operations Before stringing wire or removing de-energized conductors, a tailboard shall be held setting forth a plan of operations and specifying procedures to be followed. When crossing over energized conductors — ropes, nets and guard structures shall be installed and/or insulate the conductor. Before stringing wire or removing de-energized conductors adjacent to energized circuits, the automatic reclosing feature of the circuit interrupting device shall be disabled. Where a conductor is being pulled-in or removed and there is the possibility of the conductor accidentally contacting an energized circuit or electric field induction could be generated, the following provisions shall be made to protect the worker from the hazards of the conductor: 1. An EPZ shall be established using ground mats and barricades at both ends of the work area where the stringing equipment has been set up. 2. All stringing and tensioning equipment shall be grounded: a) Bonded to the best available ground source at the worksite. b) Bond to all other boom equipped equipment to minimize potential differences. c) Attached to ground mats at locations where workers will contact the equipment to extend areas of equipotential or, employ insulating protective equipment or barricades to guard against any remaining hazardous potential differences. 3. If a worker is not in the EPZ and within 10 feet of grounded equipment they must be wearing high-voltage rated gloves. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 43 of 50

4. A traveling ground shall be installed on the conductor 3 feet to 5 feet from the stringing and tensioning equipment. The traveling ground shall be bonded to the equipment’s grounding point with an approved grounding jumper (minimum of 2/0 Cu). 5. Protective grounds shall be installed at the traveling ground before the traveling ground is removed. When the stringing operation is complete, or when workers must contact the conductor, an EPZ shall be developed at the contact point. When changing reels of conductor, it is required to keep all conductive materials bonded as part of the EPZ. Grounding the pulling trailer to the best available ground source is required. When an existing conductor or a conductive pulling line is used to pull in new conductor, a traveling ground shall be installed and bonded to the pulling equipment with an approved grounding cable. Conductor being pulled with rope shall be grounded at the pulling end as soon as it can be reached from the ground or provisions shall be made to insulate or isolate the worker. Workers shall only make hand contact with the conductor from a working position inside the EPZ. Workers aloft or on the ground handling conductor shall work within an established EPZ. When establishing an EPZ at a pulling/tensioning site: 1. Barricade the area, allowing only one entrance/exit. 2. Install and connect EPZ ground mat radially to the best available ground source. It is not desirable to ‘invite’ the flow of fault current through the EPZ ground mats. These mats are not rated for, nor designed to carry, fault current, therefore connect the mat radially to the EPZ at the pulling/tensioning site provided that proof can be shown the EPZ is solidly bonded and in parallel with the grounding circuit and that the remotely connected grounded travelers and/or traveling ground will adequately work to clear any faults which may occur. 3. Bond all equipment together and connect to the best available earth ground. 4. Use a transfer mat or fiberglass platforms when stepping onto and off of equipment (tensioner, trailer). When transferring materials/tools into the EPZ and not using a transfer mat/fiberglass platform, an insulating method must be used. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 44 of 50

APPENDIX A Electric Field Induction and Magnetic Field Induction Introduction This section covers what is commonly called induction in the electric utility industry (technically defined as electric field induction, magnetic field induction and the “coupling effect”) and the influence it has on nearby de-energized conductors and cables. All conductors, cables and equipment, and especially Rocky Mountain Power’s transmission system, should be considered to have dangerous levels of induction until they have been tested and found safe, or proper work methods detailed in this procedure are used to eliminate the induction hazard. When current flows in an energized alternating current (AC) system (an overhead conductor or underground cable), it generates electric and magnetic fields. The fields generated by this energized AC system can “induce” a charge into nearby de-energized conductors and cables through what is called “capacitive coupling” and “inductive coupling.” The intensity of the electric and magnetic fields is directly related to the energized AC system’s voltage level, current flow and the proximity of the de-energized conductors and cables to the energized AC system. It is often thought that workers are safe contacting a de-energized conductor or cable, located in the vicinity of an energized AC system, if the de-energized conductor or cable has been grounded, when in fact the process of grounding a de-energized conductor or cable may increase the hazard to workers if grounding procedures are applied incorrectly. Electric Field Induction Electric field induction can be present any time two conductive objects are separated by a dielectric medium, such as air, creating a simple capacitor. When a de-energized conductor is separated by air from a nearby energized conductor, a process called “capacitive coupling” induces a capacitive voltage in the de-energized conductor. Any conductor energized with an AC voltage creates an electric field between the energized conductor and all other objects at different potential. There will be an electric field due to the voltage on the energized line whether current is, or is not, flowing in the energized conductor. It is measured in volts per meter (v/m). When a de-energized conductive object (overhead conductor, cable, shield wire, vehicle, tool, equipment or a worker’s body) is positioned near the energized conductor, the electric field induces a voltage onto the de-energized object through a process called “electric field induction.” Capacitive coupling has been reported even where a de-energized conductor passes perpendicularly to an energized conductor. If the de-energized object is removed from the electric field, or the electric field is eliminated, the de-energized object will retain the capacitive charge until the charge is bled off through grounding or normal discharge over a short period of time. This is commonly referred to as “trapped charge.” The electric field strength impressed on the de-energized object is related to the:  Voltage level of the energized source  Physical position of the de-energized object in relation to the energized conductor Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 45 of 50

 Distance between the de-energized object and the energized conductor  Total area of the de-energized object exposed to the electric field The voltage induced onto a de-energized object from the electric field of an energized conductor can be very high. Once the de-energized object is grounded, current flows from the now-grounded object, through the grounding equipment, into earth. Installing grounding equipment on the de-energized object will greatly reduce the induced voltage on the de- energized object. By establishing a low resistance worksite ground the voltage will be as small as possible. The electric field induction voltage will increase as the worker moves away from the location of the temporary protective grounding equipment. The voltage measured on the de-energized and grounded object will be equal to the current through the temporary protective grounding equipment, times the impedance of the ground return path. If the impedance path is very low (i.e. multi-grounded neutral, static wire, low footing resistance, etc.), the resulting voltage will also be low. However, if a temporary ground rod is used with a high earth resistance, the resulting voltage will be higher. Without proper work methods, these generated voltage and current levels can be lethal to workers. It is very important that workers never place themselves in series with the conductor, the temporary protective grounding equipment and ground when installing or removing temporary protective grounding equipment to conductors, equipment and devices. Any open point within the grounding system becomes a hazard unless continuity is maintained prior to creating the open in the grounding system. Magnetic Field Induction When AC travels down a conductor it creates an electric and magnetic field. The magnetic field contains magnetic flux developed from the AC traveling down the conductor. If a loop of wire is placed parallel to the current-carrying conductor, the varying magnetic flux created by the AC current creates an induced electromagnetic force (voltage) on the loop of wire. This voltage in turn will create current flow in the loop of wire. The magnetic process involving AC current flow, development of flux, creation of voltage and current flow in a loop of wire is called “Faraday’s law of induction.” When an energized AC transmission line carries current, a magnetic field (flux) is developed around the energized AC transmission line. When a second transmission line (paralleling the first energized AC transmission line, and in close proximity) is de-energized and grounded at different locations some distance away from each other, a conductive loop is created. The varying magnetic flux created by the AC current in the transmission line creates an induced voltage on the de-energized and multi-grounded transmission line. This voltage in turn will create current flow in the conductive loop. This process of inducing current and voltage into the de-energized and multi-grounded transmission line is also called “magnetic field induction” or “inductive coupling.” Ferranti Voltage – This is a second effect of electromagnetic induction. When installing or removing the second to last ground, there can be a voltage hazard. The potential is essentially zero at the location of the first or remaining ground and increases in proportion to the parallel length of line. Removal of grounds also causes the interruption of current flow. This creates a potential across the opening that is between the grounding device and the electric lines or equipment. This situation can create an arc. Commonly, the last ground to be removed (interruption of capacitive current) will result in the worst case arc. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 46 of 50

The voltage and current induced on the de-energized transmission line (conductive loop) is directly related to the:  Current in the energized AC transmission line  Distance between the two transmission lines  How the transmission lines are arranged (including phase configuration)  Conductor, grounding electrode and earth impedances Magnetic field induction current on long transmission lines can be eliminated by not creating the conductive loop with the de-energized conductor. Only grounding the conductor once, at the work location, eliminates magnetic field induction current in the de-energized and grounded conductor. However, when the worker makes contact with the grounded line, the worker’s body again creates a loop causing current to flow through him/her, the conductor and the grounding equipment. It is therefore important that the distance between the worker, while in contact with the conductor, and the grounding equipment be as small as possible to keep the conductive loop and resultant current below the acceptable level. (See EPZ in Section 3) The magnetic field induction and inductive coupling described above also occurs in underground cable systems when multiple sets of grounds are installed on a cable. Magnetic field induction can also develop when a conductor is grounded at one location while a section of the conductor lies on earth or a grounded surface, which occurs during storm work and new construction. It should be also noted that electric field induction will always be present with magnetic field induction. The resultant voltage and current from each phenomenon can add or subtract collectively along the length of the de-energized conductor or cable. Therefore the line must be treated as energized until an EPZ is created. Before work begins on any de-energized conductor, cable or device an assessment of the potential for induction (electric field induction and magnetic field induction) must be considered and addressed. When a conductor is de-energized from normal operating voltages, a trapped DC charge will be left on the conductor. The trapped charge will normally dissipate over a fairly short period of time (seconds), depending on the insulation, conductance and how the conductor is connected to transformers and other similar devices. However, high-voltage underground cables can retain large amounts of trapped charge for long periods of time (months) when de- energized. Special precautions must be taken when working around high-voltage de- energized underground cables that have not been grounded before the commencement of work. Ground switches at the terminals of transmission lines can be used to reduce electric field induction effects during the installation, and especially during removal of temporary PPG equipment. However, the use of ground switch(s) and PPG equipment during de-energized work can create conductive loops and potentially hazardous voltages and currents. The potential hazards of developing conductive loops with the use of ground switches and PPG equipment should be clearly understood before any work begins. Industrywide, grounding switches are becoming more important when workers must deal with high current. Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 47 of 50

They can be considered to reduce the current at the worksite, but caution about developing conductive loops must be considered before using this method. Electric Induction and Atmospheric Static Charge Wind blowing across insulated de-energized overhead conductors can accumulate a build-up of trapped charge along the conductor. This trapped charge can be removed by properly using the PPG practices specified in this procedure. Electrical storms, high winds, dust storms and slowly moving charged clouds induce an electrical charge on the surface of the earth and other objects. This process can also cause the build-up of DC trapped charge on insulated overhead conductors. When conductors are de-energized, they will retain trapped charge for several seconds to several minutes, depending on the weather and atmospheric conditions. When an energized overhead conductor crosses a de-energized conductor or device, the possibility of electric field induction effects in the de-energized conductor or device should be considered. The worker’s body may become charged if he or she is working in an electric field from a nearby energized line. The worker’s body is a floating electrode that will accumulate electrical charge from the immersion in the electric field generated from an energized conductor. This accumulated charge on the body will be discharged when the worker contacts a grounded device or structure. The voltage buildup on the worker’s body can be controlled or eliminated with the use of various methods such as:  High-voltage rated gloves (depending on the induced voltage)  Connecting the worker’s body to the line or device being worked  Using a conductive suit  Bonding the work platform to the grounded conductor or device being worked Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 48 of 50

APPENDIX B Underground Cable Grounding In underground distribution systems, tripping grounds (jumpers from the cable’s conductor to the neutral) are installed on both ends of the cable. These grounds are normally remote from the worksite unless the work is performed at the cable’s elbow. In overhead distribution systems this grounding arrangement is called bracket grounding. This method of grounding may not provide protection for workers located remotely from the cable’s grounded terminals. If workers are in contact with the grounded cable’s conductor or concentric neutral during a system fault, workers can encounter lethal step and touch potential. This method of grounding underground cables and systems can pose much higher risks to workers than overhead systems using equipotential grounding. Potentially hazardous voltage may appear at underground worksites, remote from working grounds, due to:  Accidental energization of cables or underground equipment being connected to an energized source  A backfeed through a transformer  A ground fault rise impressed on the system neutral  Human error  Equipment failure When there is a system fault while one cable of the system is de-energized and grounded to the system neutral, it is possible that there will be a transfer of potential through the cable conductor and the cable’s concentric neutral to a worksite on the cable. This transfer of potential through cable and concentric neutral could result in a hazardous voltage difference, along the length of the cable, and between the cable and ground. If protective grounding is inadequate or improperly applied, workers contacting the cable, concentric neutral or device connected to the cable, could be subjected to hazardous potential voltages. Workers standing near grounded cables or equipment could be exposed to excessive step and touch potentials if proper work procedures are not followed. To eliminate any hazard to workers in contact with the cable, or near a de-energized and grounded cable, workers must ensure that they follow one of the following procedures:  Insulate themselves from any possible potential difference between the cable and earth  Isolate themselves from any possible potential difference between the cable and earth  Provide an equipotential zone at the worksite Workers can insulate themselves from any possible potential difference between grounded cables and earth by using one or a combination of the following: high-voltage rated gloves, insulated footwear, voltage-rated tools, voltage-rated platforms or insulated voltage-rated mats. Workers can isolate themselves from any possible transfer of potential through a grounded cable by first grounding both ends of the cable by an approved method, then removing both cable grounds, and disconnecting the cable’s concentric neutral from the system neutral. Any Personal Protective Grounding Procedures Manual—PolicyTech—Safety—11/14/19. The most current version of this document is posted to Rocky Mountain Power T&D Safety pages on the intranet and to PolicyTech. Printed versions of this document may be out of date. Modification of this document must be approved by the Joint Grounding Committee. Page 49 of 50