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Subchapter 5. Electrical Safety Orders Group 2. High-Voltage Electrical Safety Orders Article 36. Work Procedures and Operating Procedures (Formerly Article 85)

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§2943. Work on or in Proximity to Underground High-Voltage Cables, Conductors or Equipment.

(a) Application. This section applies to all work on or in proximity to underground high-voltage cables, conductors or equipment, and to the operations necessary to raise or lower cables, conductors or equipment to such underground locations.

(b) Manholes, Vaults, or Similar Structures.

(1) The employer shall comply with the confined space requirements of General Industry Safety Orders Article 108.

(2) Whenever the cover is removed from a manhole, vault, or similar structure:

(A) an employee shall be stationed at the surface as long as workers are in the structure, and

(B) warning devices shall be placed so as to warn vehicular or pedestrian traffic and shall not be removed until the cover is in place.

(3) When employees are working in an underground structure, the automatic circuit recloser on the circuit being worked shall be made non-automatic when:

(A) operating energized oil type switches from inside the structure,

(B) splicing energized underground cable,

(C) patching energized lead cable,

(D) relocating energized underground cable or equipment other than minor cable movements for additional clearance or routine maintenance such as cleaning cable, fire-proofing, replacing cable support blocks, etc.,

(E) filtering or replacing oil in energized underground equipment, or

(F) the supervisor in charge deems it necessary for the safety of the employees performing the work.

(4) When employees are in an underground structure where newly installed, rebuilt or modified cable or equipment is being energized for the first time, the automatic circuit recloser on the circuit involved shall be made non-automatic.

(c) Trenching and Excavating.

(1) Trenching and excavation operations shall comply with the applicable provisions of the Construction Safety Orders.

(2) Where cable(s) exist in an excavation, such cable(s) shall be protected from physical damage during excavation.

(d) Working on Cables, Conductors or Equipment Energized at 7,500 Volts or Less.

(1) Employees shall not be permitted to cut, splice, or move cables energized at 7,500 volts or less without first obtaining permission from the employee in charge.

(2) Before cutting into a cable or opening a splice, the cable shall be identified and verified to be the proper cable.

(3) Suitable rubber gloves with protectors shall be worn when working on exposed conductors or equipment energized at 7,500 volts or less. Other exposed energized or grounded conductors or equipment in the work area, with which contact can be readily made, shall be covered with adequate protective devices, barricaded or otherwise isolated.

(4) Before breaking the electrical continuity of metallic sheaths of cables energized at 7,500 volts or less, both sides of the break shall be bonded together across the break.

(5) When working on exposed underground conductors or parts of equipment energized at 7,500 volts or less, adequate barriers or suitable protective covering shall be provided if a working space of 36 inches cannot be obtained.

(e) Working on Cables, Conductors or Equipment Energized in Excess of 7,500 Volts.

(1) When working on cables, conductors or equipment energized in excess of 7,500 volts, all exposed energized cables, conductors or equipment within reach of any part of the body shall be covered with suitable protective equipment or barricaded.

(2) The only work permitted on cables, conductors or equipment energized in excess of 7,500 volts shall be:

(A) replacing fuses, operating switches, or other operations that do not require the employee to contact energized conductors or parts of equipment with any part of the employee's body,

(B) working on the exterior of such cables or equipment, provided all current-carrying parts are effectively covered by grounded shielding or metallic enclosures, and

(C) work in the high voltage compartment of padmounted transformers and similar equipment installed above ground, provided the work is done by suitable devices. Rubber gloves shall not be considered to be suitable devices.

(3) Cables energized in excess of 7,500 volts shall be moved only under the direction of the employee in charge. Before moving cables, they shall be examined for any defects which might result in failure if the cable were moved.

(f) Working on De-Energized Cables, Conductors or Equipment.

(1) When working on de-energized cables, conductors or equipment, all exposed energized conductors or equipment within reach of any part of the body, shall be covered with suitable protective equipment.

(2) Where more than one cable exists in an excavation, cables other than the one being worked on shall be physically protected as necessary.

(3) Where more than one cable exists in an excavation, the cable to be worked on shall be identified by electrical means or spiking unless its identity is obvious.

(4) Before cutting into a cable or opening a splice, the cable shall be identified and verified to be the proper cable.

(g) Grounding De-Energized Conductors or Equipment.

(1) Any exposed ungrounded part of conductors or equipment, not worked upon in accordance with the provisions of subsections (d) or (e) above, shall not be worked upon until the following provisions have been complied with.

(A) Conductor(s) or equipment to be grounded are clearly identified and isolated from all sources of voltage.

(B) Notification has been obtained from the designated employee that all switches or other points of isolation through which electric energy may be supplied to the conductors or equipment to be worked on have been opened and are plainly tagged indicating that employees are at work, and where the design permits, they have been rendered inoperable.

(C) Visual inspection or tests are made to insure that cable(s), conductor(s) or equipment have been de-energized.

(D) Guards or barriers are installed as necessary to prevent contact with exposed energized conductors or equipment.

(E) Grounds are applied except where their installation or use increases the working hazard. Grounds shall be permitted to be removed for test purposes.

(F) Suitable grounding devices shall be used. They shall be first connected to a ground before being brought into contact with any de-energized conductors or equipment to be grounded. The other end shall be attached and removed by means of insulated tools or other suitable devices. When removed, they shall be removed from all conductors or equipment before being disconnected from ground.

(G) When required, there shall be a minimum of one ground on the conductors or equipment being worked on:

1. between the place where the work is being done and each possible source of supply,

2. at the work location, or

3. as close as practicable to the source of supply.

(H) One of the grounding devices shall be visible to at least one member of the crew unless one of the grounding devices is accessible only to authorized persons.

(I) Grounding devices shall be capable of conducting the anticipated fault current and shall have a minimum conductance of No. 2 AWG copper.

(J) When more than one independent crew requires the same cable(s), conductor(s) or equipment to be de-energized, a tag for each such independent crew shall be placed on the cable(s), conductor(s) or equipment. Where clearances for such independent crews are controlled by a designated authority having immediate jurisdiction over the cable(s), conductor(s) or equipment involved only one tag need be installed.

(2) Upon completion of work the employee in charge of each independent crew shall determine that all employees in the crew are clear, and shall report to the designated authority that all tags protecting the crew may be removed.

(3) Prior to the energizing of the cable(s) or equipment, the employer shall ascertain that all employees are clear and all grounds are removed.


Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Editorial correction of section heading and subsection designations filed 11-2-83 (Register 83, No. 45).

2. Amendment filed 12-10-87; operative 1-9-88 (Register 88, No. 1).

3. Amendment of subsection (b)(1) filed 9-26-2001; operative 10-26-2001 (Register 2001, No. 39).

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