Guidelines for meeting National Electrical Code (NEC) Grounding Requirements for Portable Generators Supplying Portable Equipment in the Motion Picture and Television Industry
The frame of the generator mounted to a truck or trailer may serve as the grounding electrode (in place of the earth) for the portable power distribution system. A ground rod is not required if the generator units and vehicles they are mounted to are insulated from the earth.
Two or More Generators
- Where two or more portable generators are located within 20 feet or less of each other they shall be bonded together by a dedicated bonding conductor from generator to generator. The bonding conductor shall be copper and sized in accordance with NEC Table 250.122. A ground rod is not required if the generator units and vehicles they are mounted to are insulated from the earth.
- Generators shall be bonded together when two or more generators supply power to a common set where the portable equipment is in close proximity to each other (within 12 feet for interior sets, 20 feet for exterior sets).
Portable Generator Supplying Power to Portable Equipment in a Structure
- In a de-energized building the grounding requirements are the same as an exterior location.
- When a portable distribution system is brought into an energized structure, where structure power is not used for production power, bonding to the structure’s grounding electrode is not required.
Generator Supplying Portable Power in Combination with Structure Power
Using a portable power distribution system inside a structure in combination with the structure’s power supply, or where large metal equipment supplied by the structure’s power may come in contact with the portable power distribution system or equipment, requires the generator grounding conductor to be bonded to the structure’s grounding electrode, and the conductor shall be sized according to NEC 250.66. The grounding electrode is usually found at the structures electrical meter.
Generator Supplying Portable Power to Portable Equipment Attached to a Structure
Motion Picture and Television productions do not energize permanently installed systems that are no longer connected to utility power, unless supervised by a licensed electrician.
Connecting to Structures Utility Power
Only a qualified person shall perform tie-ins to premises wiring. Tie-ins need to be protected from contact, barricaded and have proper overcurrent protection.
Ground Fault Circuit Interrupter
NEC Section 530.6 allows short-term outdoor use of standard non-GFCI protected indoor portable stage and studio lighting equipment and portable power distribution equipment.
NEC Section 530.21 does not require GFCI protection for plugs and receptacles used in Motion Picture and Television Studios and on Locations.
GFCIs are devices intended for the protection of personnel only. The code requires GFCI protection for certain permanently installed receptacles on premises or permanent structure wiring (NEC Article 210) and on construction sites (NEC Article 590). Motion Picture and Television productions typically use GFCIs in wet conditions or when systems or energized devices come within 10 feet of water.
Portable Generators 5 Kilowatts or less (Putt-Putt)
These generators shall meet the same isolation and bonding requirements of larger portable generators.
All electrical equipment (required to be grounded) is to be grounded back to the point where the electrical system receives its source of power. Even though Direct Current equipment operating at less than 150 volts to ground is not required to be grounded, it is highly recommended for safety purposes.
Electrical equipment grounding conductors are to be continuous from the load being served back to the source of power. Approved cable connectors and devices will be considered as part of the continuous conductor. The grounding conductors are to be sized according to the rating of the overcurrent device protecting the circuit supplying the individual piece, or group, of equipment. (20 Amp – #12, 30/60 Amp – #10, 100 Amp – #8, 200 Amp – #6, 300 Amp – #4, 400 Amp – #3, 500 Amp – #2, and 600 Amp – #1 AWG)
Flexible cord or multiple conductor cable (enclosed in an overall jacket) supplying circuits or equipment are to be connected by use of a polarized plug and receptacle. Larger single conductor cables may be connected with listed single pin plugs or connectors. So called alligator clamp connectors should never be used for grounding connections. The basic design of these alligator types of connectors does not provide a suitable grounding connection. Unless designed for the purpose, connectors or splices shall be suitably isolated from contact with live vegetation, damp or wet locations.
Generators, Truck or Trailer Mounted
Generators mounted on trucks or trailers shall be completely insulated from earth by means of rubber tires, rubber mats around metal stairways and rubber mats under any type of lift-gate or jacking device. Metal supports for trailers shall be insulated by means of wooden blocks. Safety tow chains shall be secured so as to not touch the ground.
Generator Grounding Connections (when required)
Interior water pipes, interior metal fixtures, metal frames of buildings, and the building grounding electrode system shall not be used as a grounding connection for mobile generators supplying power exclusively to location production systems.
When mobile generators supply power to location production systems in addition to the building’s electrical system, the generator’s grounding connection shall be bonded to the main building grounding electrode system at the service.
Multiple generators shall have their grounding connections bonded to each other when located within 20 feet of each other or when one supplies equipment which might possibly come within 20 feet of equipment supplied by the other(s).
Conductors and cables should never be loaded in excess of 100% of their actual ampacity. The rating of the overcurrent device (i.e., fuse or circuit breaker) should never be confused with the rating of the conductors or cables.
Rating for Conductors and Cables
The California Electrical Code assigns ampacity ratings for conductors and cables used in motion picture production which are higher than the commonly used ratings. These ratings are found in table 400-5(B), apply only to cable types SC, SCE, SCT, PPE, G and W, and requires that the cable be installed per the footnotes. Ampacities for the commonly used distribution cables are AWG 4/0-360 amps, AWG 2/0-265 amps, AWG #2-170 amps. Note that ampacities listed in column D in the 75 degree C (167 degree F) section are used because 75 degrees C is the maximum rating of termination points.
Rating of Overcorrect Devices
The California Electrical Code requires conductors and cables to be protected by overcurrent devices rated at not more than 400% of the ampacity given in table 400-5(B). Some generators have overcurrent devices rated as high as 1200 amps. Suitable overcurrent devices must be installed to protect the smallest size conductor or cable between the generator and the distribution box (typically AWG #2 “banded” cable).
The 400% rating of the overcurrent device does NOT mean that the cable or conductor may be loaded beyond the ampacity rating given in the table!
A branch circuit of any size supplying one or more receptacles shall be permitted to supply stage set lighting loads. A branch circuit is defined as the circuit conductors between the final overcurrent device protecting the circuit and the outlet(s). Twenty amp circuits supply equipment rated up to 2000 watts (16 amps), fifty amp circuits supply 5K’s, hundred amp circuits supply lOK’s. Some equipment is marked with the maximum overcurrent protection permitted.
General Equipment Requirements
All equipment, new and existing, shall comply with the minimum requirements for safety of the Los Angeles Municipal Code. All existing equipment shall be maintained in an electrically safe condition with NO exposed live parts that in any way will present a potential shock or fire hazard.
All equipment shall be provided with overcurrent protection as required by the California Electrical Code. All cables and flexible cords shall be of the types permitted by Articles 400, 520 and 530 of the California Electrical Code and those specifically approved by City of Los Angeles. Welding cable shall not be used.
All Alternating Current (AC) supplied HMI fixtures and ballasts shall be grounded by a continuously connected equipment grounding conductor back to the source of power. These shall not be grounded to the nearest available water pipe connection. This also applies to Direct Current supplied units where grounded. All electrical equipment required to be grounded shall be grounded only by the California Electrical Code required methods and devices.
All electrically powered equipment (except cameras, radios, audio equipment and the like that have self-contained power sources) shall be listed by a laboratory approved by this department. Equipment that does not bear the listing mark of an approved laboratory shall not be used.
General Safety Precautions
Installation Connections and Disconnections
Connections shall be made in the following order:
- Equipment grounding conductor
- Grounded conductor (neutral)
- Ungrounded conductors (hot conductors)
Disconnection shall be in the reverse order.
All connections shall be made from the farthest load connection first, and then progressively toward the source of supply. All disconnections shall be made in the reverse order.
Guarding of Live Parts
In any part of a location distribution system that may potentially have exposed live parts, precautions shall be taken to assure they are covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of any contact by objects or persons.
As 480 volt systems become more common on production, employees working with them should be aware of the potential hazards which are greater than 120 volt systems. Such hazards include, but are not limited to, greater arc flash potential, arc blast explosions, significantly greater shock hazard, and a greater ability to arc between conductive surfaces.
Only qualified employees who have been properly trained and authorized by the employer should connect, disconnect, or operate 480 volt systems or equipment.
This Safety Bulletin is intended to identify potential hazards and to recommend safe practices for trained personnel. This Safety Bulletin is not intended as a design specification, nor is it intended as an instruction manual for untrained persons.
Identifying Source Voltage for Cord and Plug Connected Devices
Distribution board, panel board and disconnect switch enclosures can only be opened by qualified and designated person(s). Prior to connecting onto or energizing any 480 volt system, the source voltage must be identified and verified. Proper and safe meter techniques must be observed to prevent arcing. An appropriately rated voltage meter must be used. Employees using test equipment on 480 volt systems shall receive proper training prior to metering the source power.
Color Coding for Voltage and Phase Identification
Portable cables and conductors MUST be color coded to ensure that 120 volt equipment is not mistakenly connected to a 480 volt system.
Neutral conductors shall be identified by marking at least the first 6 inches from both ends of each length of conductor with GRAY (white is to be used for 120 volt neutral conductors).
Grounding conductors shall be identified by marking at least the first 6 inches from both ends of each length of conductor with GREEN or GREEN WITH YELLOW STRIPES.
Phase conductors (hots) shall be identified by marking at least the first 6 inches from both ends of each length of conductor with BROWN, ORANGE or BRIGHT YELLOW tape.
Where more than one voltage system exists within the same location, each system shall be identified by voltage and system. This can be done by additional color coding, marking tape, tagging, or other equally effective means.
Where color coding is used to distinguish between different lengths or owners of cable, it must be done so that there is no confusion created.
To avoid confusion between different nominal voltage systems, YELLOW SHOULD NOT BE USED IN PORTABLE 120 VOLT SYSTEMS.
All 480 volt systems shall be grounded in accordance with NEC Article 250 and additional requirements, if any, of the Authority Having Jurisdiction (“AHJ”).
Special attention should be taken when using multiple power sources whose energized systems may come into contact with each other. Ensure systems are bonded together with the appropriately sized bonding jumper and connected to a common grounding electrode to ensure that no potential exists between the system grounds.
If grounding rods are required, use proper sized grounding rods and connectors as per the NEC.
Before driving grounding rods into the earth, an underground service company should be contacted to make sure the area is clear of hidden hazards such as water pipes, gas lines, buried cable, and other obstructions.
Grounding conductors from portable 480 volt sources used in buildings should be connected to the grounding connection at the service entrance or main power source.
Devices and Cables
All cable shall be listed for its intended use by an approved testing laboratory.
Dual jacketed type “W” or equivalent cable is recommended for single conductor feeder cables on 480 volt power systems since small punctures and fractures in the insulation may not be seen during visual inspection.
Single conductor connectors used on “hots” and “neutrals” shall be connected to the conductors by means of solder, set-screw, or crimping. Equipment grounding conductor connection devices or fittings that depend solely on solder shall not be used. Single conductor connectors shall be of the single pole and locking type.
Spider boxes, splicing blocks, and other distribution equipment shall be rated and identified for use on 480 volt systems in conformity with the provisions of the NEC. When more than one voltage system is used on the same premises, the equipment shall be marked in a suitable manner to identify the system to which they are connected.
Cables and devices must be protected from foot and automobile traffic. When using elevated truss crossovers, the metal structure must be grounded to the source ground.
When 480 volt equipment is mounted, suspended, or otherwise attached to any structure which uses metal in its construction (e.g., scaffold, truss, greenbeds, or pipe grids), the metal components of the structure must be grounded to the source ground.
480 volt systems should be elevated and/or protected in such a manner to avoid contact with water.
When 480 volt systems may be used in or around water, such systems shall be designed and listed for use in water or wet conditions (e.g., NEMA 3R enclosures, GFCI devices).
Plugging and Unplugging Electrical Equipment
Visually inspect the condition of the plug, cable, and equipment for any signs of excess wear, loose parts, frayed cables, cracked/punctured insulation, pinched/crushed outer
jacket, exposed current-carrying parts or any other signs of damage. DO NOT USE equipment in any of these conditions. Label and return this equipment for repair.
All grounded equipment should be tested for continuity between the ground pin on the plug and the metal parts of the lighting equipment before it is placed into service.
Turn off the power when connecting to, or disconnecting from, 480 volt systems. When branching off an energized system, shut off the power and lock-out/tag-out all switches that may energize the circuit being worked on. All equipment that is being plugged and unplugged shall be in the off position to avoid creating an arc at the receptacle. Verify with the appropriate meter that the power is turned off. Proper Personal Protection Equipment (PPE), including protective gloves and clothing, shall be worn to avoid getting burned from a flash created by a short-circuit in the equipment.
Connecting Order of Single Conductors
All single conductor connections shall be made in the following order:
Disconnect in the reverse order:
All multi-pole connectors shall provide for “first make, last break” of the ground pole.
Guarding of Live or Non-Insulated Parts
Any part that is live or non-insulated must be covered with appropriate insulation material or protected or barricaded to prevent accidental contact by persons or objects.
Electrical accidents are very serious and care must be taken to ensure that potential rescuers do not become victims. If an electrical accident occurs, follow proper emergency procedures and have Emergency Medical Services (“EMS”) contacted immediately. do not approach any electrical accident until you have been notified by qualified personnel that it is safe to approach.
Properly secure the accident area to prevent the possibility of additional victims.
Do not touch a victim of electrical shock while he or she is connected to the circuit. If safe to do so, turn off the power.
While waiting for EMS to arrive, and if trained, follow proper procedures for Cardiopulmonary Resuscitation (“CPR”), including the use of an Automated External Defibrillator (“AED”), if available.
Since the possible effects of electrical shock can manifest hours after the event, any victim of electrical shock must be evaluated by a qualified medical professional.
All electrical systems and electrically energized equipment are potentially hazardous, whether Alternating Current (AC) or Direct Current (DC), whether 50 volts, 120 volts or higher.
Only employees authorized by the employer to do so shall connect, disconnect, or operate electrical distribution systems. Prior to energizing any systems, ensure that all personnel are clear of all electrical equipment connected to the system.
This Safety Bulletin is intended to identify potential hazards and to recommend some specific safe practices for trained personnel. This Safety Bulletin is not intended as a design specification or as an instruction manual for untrained persons.
This document serves as minimum guidelines to the use of Portable Power Distribution Systems and other electrical equipment. Local Authorities Having Jurisdiction (“AHJ”) may have requirements that are more restrictive. Always adhere to the National Electrical Code (“NEC”), all applicable Federal, State, and Local laws and regulations, and the determinations of the AHJ.
General Safety Measures
1. Plugging and Unplugging Electrical Equipment
Visually inspect the condition of the plug, cable, and equipment for any signs of excess wear, frayed cables or exposed current-carrying parts. DO NOT USE any equipment that is damaged.
All grounded equipment should be tested for continuity between the ground pin on the plug and the metal parts of the equipment before it is put into service. In addition, all cables should be tested for continuity of the ground, neutral and phase conductor.
Verify all equipment is in the OFF position prior to plugging or unplugging to avoid creating an arc at the receptacle. Wear protective gloves to avoid injury from a possible flash created by a short-circuit in the equipment.
Do not pull on the cord when unplugging equipment. This can cause one or more of the wires to pull out of its termination in the plug. Always grasp the plug firmly to unplug.
When using both AC and DC systems in the same location, each system must be clearly identified as AC or DC. Always verify that you are not plugging AC equipment into DC systems or DC equipment into AC systems.
2. Replacing Fuses and Circuit Breakers
Over-current protection is one of the most vital parts of the electrical circuit since improper over-current protection leads to fire and/or damage to equipment.
Before attempting to replace a fuse, turn off and verify the circuit is de-energized.
Fuses should only be replaced by qualified personnel. Fuses come in a wide variety (e.g., one-time, time-delay, slow-blow, dual-element, etc.). When replacing a blown fuse, be sure to select a fuse of proper voltage, interrupting capacity, and amperage for the application.
Over-current protection must be sized according to the ampacity of the conductors and equipment served as per the NEC Table 400.5A or B for flexible cords and cables.
Disconnect switches still contain energized parts within the switch even in the OFF position. Because these disconnect switches may contain more than 400A and up to 480V, the use of properly-rated Personal Protective Equipment (PPE), including gloves and eye protection, is required. Pliers and other tools not designed for fuse replacement shall not be used. The use of insulated, specialized fuse-replacement tools is required when replacing fuses in disconnect switches.
An overloaded circuit or equipment failure will cause circuit tripping or blown fuses. NEVER use oversized fuses, circuit breakers, copper slugs or tubing to replace fuses.
Follow proper over-current protection per the NEC.
3. Power Tools
When using power tools that are not double-insulated or battery powered on construction sites, Ground Fault Circuit-Interrupter (GFCI) protection is required. Test the GFCI device before use to verify it is functioning properly.
Insulating platforms, rubber gloves, and rubber mats provide an additional safety factor when working with electrically powered tools in damp locations.
Electrical Systems Safety Measures
1. Rigging a System
Use proper lifting techniques when lifting or moving heavy objects, such as cable or lighting equipment. Do not step directly on equipment such as cable. Cables can roll underfoot causing a slip or fall hazard.
The electrical system should be de-energized while it is being rigged. Before energizing the system, verify that the system is free from short circuits and/or crossed wires and verify all connections are properly mated.
2. Connecting Order of Single Conductors
All single conductor connections shall be made in the following order:
- Grounds (all AC, and on DC where used)
- Phase Conductors (Hots)
Disconnect in the reverse order:
- Phase Conductors (Hots)
- Grounds (all AC, and on DC where used)
All multi-pole connectors used on AC shall provide for “first make, last break” of the ground pole.
3. Color Coding
Portable cables and conductors shall be color coded in accordance with the NEC.
Neutral conductors shall be identified by marking at least the first 6 inches of both ends of each length of cable with white or gray.
Grounding conductors shall be identified by marking at least the first 6 inches of both ends of each length of cable with green or green with yellow stripes.
Phase conductors (hots) shall be identified by marking at least the first 6 inches of both ends of each length of cable with any color other than green, green with yellow stripes, white, or gray.
Commonly used colors for phase conductors (hots) on 120V systems are red, black and blue. Commonly used colors for phase conductors (hots) on 480V systems are brown, orange and yellow.
Where more than one voltage system exists within the same premises, each system conductor shall be identified by the system to which it is connected. This can be done by separate color coding, marking tape, tagging, or other equally effective means.
Where color coding is used to distinguish between different lengths or owners of cable, it must be done in a way that will not create confusion.
Caution should be used when using the color yellow as it may appear white under sodium lighting.
4. Devices and Cables
Cables and devices should be protected from foot and vehicle traffic damage.
Electrical distribution systems should be elevated in such a manner that they will not come in contact with running or standing water.
When it is necessary to have electrical distribution systems and devices which come into contact with water, such systems shall be designed and listed for use in water.
When lighting, electrical distribution, or any electrically powered equipment is used in close proximity to water or can make contact with water, the use of GFCI should be evaluated by a qualified person. This includes all areas where water hazards exist. When persons, wardrobe, props, or equipment are wet, the need for GFCI protection should be evaluated.
GFCIs should not be used on circuits where removal of power may create a greater hazard, such as airbags, decelerators, emergency egress lighting, etc.
Alligator clips or clamps shall not be used in conjunction with any electrical system or equipment.
Two-wire, non-polarized, DC-plugging boxes, paddle plugs, and porcelain boxes are not permitted on AC systems. This applies even with the use of an external ground.
All gang boxes supplied by a connector plug with an ampere rating higher than the receptacles in the gang box shall contain fuses or circuit breakers sized according to the ampere rating of those receptacles.
All AC multi-pole connectors shall be grounded and polarized.
All cable shall be listed by an approved testing laboratory. Only types “G,” “W,” or Flexible Stage and Lighting Power Cable (EISL, SC, SCE, SCT) are acceptable for single-conductor feeder cables.
Single-conductor connectors used on phase conductors and neutrals shall be connected to the conductors by means of solder, set-screw, or crimping. Flexible cords and cables shall be connected to devices and to fittings so that tension is not transmitted to joints or terminals.
Equipment Grounding Conductor connection devices or fittings that depend solely on solder shall not be used.
5. Guarding of Energized Parts
Any exposed or non-insulated part of the distribution system must be considered as energized until verified otherwise. and protected from accidental contact. Any point of danger, including the arc flash boundary, should be protected, shielded or barricaded to prevent any possible entry by unauthorized persons or objects.
6. Portable and Vehicle Mounted Generators
Approach to exposed connections on portable and vehicle mounted generators should be physically restricted or barricaded to non-qualified persons. Any
generator with exposed busbars or other energized parts should be guarded as described in Section 5 of this document.
Read thoroughly any operational manuals and complete appropriate forms and logs provided with the generator. Only a qualified operator designated by the employer shall operate a generator.
A fire extinguisher specific for the generator unit must be present and readily accessible outside the generator enclosure. Refer to studio policy on employee use of fire extinguishing equipment.
The generator should have as much open space as possible on all sides to allow maximum ventilation and minimum interference. It is important that all generating sets be protected from the elements and from unauthorized access.
The following precautions must be taken when re-fueling the generator:
- The generator must be off.
- A listed fuel nozzle must be used to prevent static electricity build-up.
- Connect a ground bond from the frame of the re-fueler to the frame of the generator.
Make sure exhaust fumes are ventilated away from enclosed areas, personnel, and air intake ducts, such as trailers and buildings. Be aware of hot surfaces when working around a generator.
Portable AC generators shall comply with the NEC, Section 250.34.
Vehicle mounted generators mounted on the same frame as the equipment they are supplying shall be completely insulated from earth by means of rubber tires, rubber mats around metal stairways and rubber mats under any type of lift gate or jacking device. Metal supports for trailers shall be insulated by means of wooden blocks. Safety tow chains shall be secured so as to not touch the ground. If complete insulation is not possible, a grounding electrode system shall be installed per the NEC, Section 250.52.
Earth grounding of portable generators shall comply with applicable sections of Article 250 of the NEC as determined by the AHJ.
Portable generators that produce both AC and DC are not producing pure direct current, and must not be used in DC mode around water. GFCIs will not function when supplied by DC.
7. Generator Grounding Connections
Generators shall be grounded in accordance with Article 250 of the NEC.
Fire hydrants, interior metal pipes, fixtures, standpipes or metal frames of buildings SHALL NOT BE USED as a grounding connection for mobile generators, unless approved by the AHJ.
8. Portable Transformers
Portable transformers shall be used, grounded, and bonded in accordance with the NEC, all applicable Federal, State and Local laws and regulations, and the determinations of the AHJ.
The ground of all transformers shall be connected to the ground of the supplying power source.
Proper clearance and ventilation shall be maintained around the transformer. Verify the ground is bonded to the neutral inside the transformer.
9. Bonding of Separately Derived Power Sources
The grounds of separately derived power sources must be bonded together when located within 20 feet of each other or when one power source supplies equipment that may come within 20 feet of equipment supplied by another power source. When filming on interior sets this distance may be reduced to 12 feet.
When supplemental power is provided to a building (where allowed) and/or is supplying additional power inside the building, the ground of the supplemental power source must be bonded to the building’s grounding electrode system.
The size of the bonding conductor(s) shall not be less than that given in NEC Table 250.66.
10. Grounding Direct-Current Equipment
DC-supplied equipment operating over 150 volts shall be grounded. Care should be taken to provide a barrier, either of material or space, between grounded and non-grounded devices.
When using 2-wire, ungrounded equipment on DC, verify there are no grounded metal surfaces, such as green beds, pipe grids or scaffolding, within 12 feet of the DC equipment.
11. Grounding Alternating-Current Systems and Equipment
All AC-supplied systems and equipment used by the motion picture and television industry shall be grounded.
All AC-supplied equipment shall have all non-current-carrying metal parts grounded by a continuously connected, equipment-grounding conductor back to the source of power. This conductor shall be sized according to NEC Table 250.122 .
12. Connecting to Premises/House Electrical Power Source (tie-in)
Connecting to a premises/house electrical power source (tie-in), such as a panel board or switchboard, can create the risk of a serious or fatal accident. Such connections shall only be made by a qualified person. Before performing this work, check with the NEC, all applicable Federal, State and Local laws and regulations, and the determination of the AHJ.
At a minimum, the AHJ will require that a qualified person possess:
- The skills and techniques necessary to distinguish exposed live parts from other parts of electrical equipment.
- The skills and techniques necessary to determine the nominal voltage of exposed live parts.
- The knowledge of working clearance distances specified for various voltages to which personnel will be exposed, including arc-flash and shock-protection boundaries.
- The knowledge of lockout/tagout procedures and access to lockout/tagout equipment.
- The knowledge of proper use of personal protective equipment, insulating and shielding materials, and insulated tools.
- The knowledge to not wear jewelry, conductive clothing, and other unsuitable synthetic apparel when working on or around electrical equipment.
- The knowledge to select, inspect and use appropriate electrical test equipment.
- The necessary credentials and/or the ability to obtain required permits.
- The knowledge to perform proper emergency procedures.
Unless the electrical system of a building has been properly de-energized, locked out/tagged out, and verified to be de-energized, assume the electrical panel is energized.
Energized parts with which a person could make contact must always be de- energized, unless:
- The de-energization of the system is not possible, due to the design of the equipment.
- The de-energization of the system will cause an additional hazard, such as deactivation of emergency systems.
- The electrical system supplies circuits that form an integral part of a continuous process that would need to be completely de-energized in order to work on the panel or circuit.
When unable to de-energize the circuit, and where the possibility exists of personnel coming in contact with energized equipment, equipment shall be properly insulated as described in Section 5 of this bulletin.
The use of an in-house “Energized Electrical Work Permit” system as described in NFPA 70E is recommended to determine the necessity of the energized work and to ensure that all parties involved are aware of the hazards associated with connecting to an energized power source, including potential hazards to other systems that are connected to the power source.
Connecting to an energized system is strongly discouraged. If work on energized electrical equipment is necessary, at a minimum, you must follow the arc-flash hazard-analysis label (if present) to determine the hazard/risk category and associated PPE required to prevent injury or death. In lieu of a label, consult and follow NFPA 70E Table 130.7(C)(9) requirements.
Remember, always consider exposed electrical parts to be “energized” until you have verified they have been de-energized and locked out/tagged out.
Obtain an electrical permit from the appropriate AHJ before such work is done. Any connection to a premises/house electrical power system shall be performed by a qualified in-house electrician. If a qualified in-house electrician is not available, the work shall be performed by a qualified electrical contractor or other qualified person.
Prior to a qualified person connecting to a premises/house electrical power system, the following requirements, among others, must be adhered to:
- Determine if the electrical system voltage is compatible with the equipment to which it will be connected.
- Calculate the electrical panel’s existing maximum ampere load to determine if the remaining capacity is sufficient for the additional equipment being connected.
- Use a properly sized circuit breaker or fusible disconnect switch to connect a distribution system to the premises/house electrical power system.
- The rated interrupting capacity of the circuit breaker or fuses must meet the available interrupting capacity at the point of connection to the premises/house electrical power system.
- Use only approved lugs or devices to connect to the panel bus.
- Never use “Alligator” type clamps.
- Never connect ahead of the main circuit breaker, fuse box, or meter.
- If required, obtain a permit to remove a panel cover.
- Use suitable barriers, partitions, or other means to limit access to the connection to protect against accidental contact with energized parts and unauthorized entry into the arc-flash boundary by unauthorized persons or objects.
- Replacement of all panels, covers and screws must be done by a qualified person immediately after disconnecting from the premises/house electrical power system.
13. Personal Protective Equipment (PPE)
All persons working on or near energized electrical equipment shall wear PPE appropriate for the level of electrical hazard to which they are exposed. This PPE may include non-melting, long-sleeved shirts and long pants, or other Arc Rated (AR) clothing, and closed-toed, nonconductive-soled shoes and Safety Glasses. Garments made from synthetic materials not manufactured specifically for electrical work, such as polyester and nylon, are not suitable to protect from electrical hazards.
For an extended list of common motion-picture/television tasks and associated PPE refer to Addendum D. This addendum is based on NFPA 70 E and will be updated as warranted.
Refer to NFPA 70E Tables 130.7(C) (9) and (10) for a full list of tasks performed
on energized equipment, the associated hazards/risk categories, and required PPE.
14. Emergency Response
If an electrical accident occurs, notify emergency medical personnel and activate the Emergency Action Plan.
An Emergency Action Plan should include the following items:
- Location, method and any necessary tools required for emergency power disconnection
- Emergency Medical Services on hand or readily available with working means of contact
- Exact location of where the work is being performed
- Identification of CPR Trained Personnel
- Location of available AEDs
do not approach any electrical accident until you have been notified by qualified personnel that it is safe to approach.
Properly secure the accident area while maintaining a safe distance to prevent the possibility of additional victims.
DO NOT touch or approach a victim of electric shock while he or she is being shocked. If safe to do so, turn off the power.
Trained personnel should follow proper procedures for Cardiopulmonary Resuscitation (“CPR”) and Automated External Defibrillator (“AED”) use.
Since the possible effects of electrical shock can manifest hours after the event, any victim of electric shock must be evaluated by a qualified medical professional.