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(a) The following shall be permanently and effectively grounded before the associated high-voltage equipment is energized.
(1) Metal conduit, cable armor, and other metal raceways or enclosures for wire and cable.
(2) Lightning arrester ground terminals and such other equipment.
(3) Non-energized metal parts of all fixed equipment and associated fences, housings, enclosures, and supporting structures.
(b) Effective grounding of all equipment shall be assured by the use of an equipment grounding conductor, where feasible, such that the path to ground will:
(1) Be permanent and continuous.
(2) Have ample ampacity to conduct safely any currents liable to be imposed upon it.
(3) Have impedance sufficiently low to limit the potential above ground, and to facilitate the operation of the overcurrent or ground fault detecting devices in the system. Where the conduit is intended to function as the equipment grounding conductor, approved threaded couplings, hubs, and joints, or double locknuts and bushings with bonding jumpers are required.
(c) Unless grounding conductors are an integral part of the cable, they shall be no smaller than No. 6 AWG for mechanical strength. Grounding conductors shall be of corrosion-resistant approved material, or shall be suitably protected against corrosion, and shall have thermal capacity for the conditions imposed on them by the system.
(d) Grounding connections shall be clamp type, pressure type, welded, or other approved types. Solder-type connections shall not be used for grounding.
(e) Grounding electrodes shall be of corrosion-resistant material, and the size number, and the location shall be adequate to provide effective grounding of the equipment.
(f) Local piping systems, well casings, building frames, and the like shall not be used as grounding electrodes unless their resistance to ground will be maintained low enough to insure effective grounding.
(g) Noncurrent-carrying metal parts of all portable equipment shall be grounded.
(h) Specific Exceptions.
(1) Grounding of equipment mounted on poles shall comply with Rules 58.3-C and 58.4-C, General Order No. 95, 1981 Edition Rules for Overhead Electric Line Construction of the California Public Utilities Commission, which are hereby incorporated by reference.
(2) Where high-voltage equipment and associated metal enclosures or structures are intentionally isolated from ground, provision shall be made to prevent any person who can make contact with ground from contacting the isolated equipment and associated metal enclosures or structures when such equipment is energized. Intentional grounds shall be applied after such equipment is de-energized and before access is permitted, in accordance with Work Procedures, Article 36.
(Title 24, Part 3, Section 250-155.)
NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
HISTORY
1. Editorial correction filed 11-2-83 (Register 83, No. 45).
2. Amendment of subsections (c) and (h) filed 12-10-87; operative 1-9-88 (Register 88, No. 1).
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