Using MC cable for temporary power on a construction site
Reviewed by Julie Gunn, Head of Services, SALUS Safety
The question, as asked: Can I use MC Cable for temporary power on a construction site?
A person submitted this question to Rosie's free generator. The asker's identity is neither imported nor published.
Rosie's answer
Published by SALUSTemporary wiring for electrical power and lighting must adhere to specific safety requirements. These installations are allowed to be of a lower class than permanent wiring but must still comply with the subpart requirements for permanent wiring, unless explicitly modified. Temporary wiring must be removed immediately after the construction or purpose for which it was installed is completed. [1]
General requirements for temporary wiring include:
- Feeders must originate in a distribution center and be run as multiconductor cord or cable assemblies, within raceways, or as open conductors on insulators spaced no more than 10 feet apart where not subject to physical damage.
- Branch circuits must originate in a power outlet or panelboard and be run as multiconductor cord or cable assemblies, as open conductors, or in raceways. All conductors must be protected by overcurrent devices at their ampacity. Open conductors should be located where they will not be subject to physical damage and must be fastened at intervals not exceeding 10 feet. Branch-circuit conductors are not allowed to be laid on the floor. Each branch circuit that supplies receptacles or fixed equipment must contain a separate equipment grounding conductor if run as open conductors.
- Receptacles must be of the grounding type. Each branch circuit, unless installed in a complete metallic raceway, must contain a separate equipment grounding conductor, with all receptacles electrically connected to the grounding conductor. Receptacles for temporary lighting should not be installed on branch circuits supplying temporary lighting and must not be connected to the same ungrounded conductor of multiwire circuits which supply temporary lighting.
Sources used for this answer
[1] Safety and Health Regulations for Construction (OSHA 29 CFR 1926) - 1926.405 - Wiring methods, components, and equipment for general use
Page 2
Open source documentSource excerpt
# Temporary wiring- 1926.405(a)(2)(i) Scope. The provisions of paragraph (a)(2) of this section apply to temporary electrical power and lighting wiring methods which may be of a class less than would be required for a permanent installation. Except as specifically modified in paragraph (a)(2) of this section, all other requirements of this subpart for permanent wiring shall apply to temporary wiring installations. Temporary wiring shall be removed immediately upon completion of construction or the purpose for which the wiring was installed. 1926.405(a)(2)(ii) General requirements for temporary wiring. ## 1926.405(a)(2)(ii)(A) Feeders shall originate in a distribution center. The conductors shall be run as multiconductor cord or cable assemblies or within raceways; or, where not subject to physical damage, they may be run as open conductors on insulators not more than 10 feet (3.05 m) apart. ## 1926.405(a)(2)(ii)(B) Branch circuits shall originate in a power outlet or panelboard. Conductors shall be run as multiconductor cord or cable assemblies or open conductors, or shall be run in raceways. All conductors shall be protected by overcurrent devices at their ampacity. Runs of open conductors shall be located where the conductors will not be subject to physical damage, and the conductors shall be fastened at intervals not exceeding 10 feet (3.05 m). No branch-circuit conductors shall be laid on the floor. Each branch circuit that supplies receptacles or fixed equipment shall contain a separate equipment grounding conductor if the branch circuit is run as open conductors. ## 1926.405(a)(2)(ii)(C) Receptacles shall be of the grounding type. Unless installed in a complete metallic raceway, each branch circuit shall contain a separate equipment grounding conductor, and all receptacles shall be electrically connected to the grounding conductor. Receptacles for uses other than temporary lighting shall not be installed on branch circuits which supply temporary ligh…