The requirements for temporary wiring for power and lighting purposes include provisions for wire connections, junction boxes, and overcurrent protection, as well as the use of conductors. See NEC Article 305.

8.1.10.1 SERVICE CONDUCTORS

Service conductors shall comply with all the provisions of Article 230 in the NEC when they are used as wiring methods to supply temporary power systems.

8.1.10.2 FEEDER CONDUCTORS

Feeders are the conductors that transmit power from the service equipment to the distribution panelboard or between the main disconnect and the branch circuit over current devices (circuit breakers, fuses). Feeders for temporary wiring shall originate inside an approved distribution center, such as a panel board, that is rated for the voltages and currents the system is expected to carry. Some equipment is manufactured specifically for temporary use.

Feeders can be run as cable assemblies, multiconductor cords, or cables with two or more conductors each with their own insulations, run together in the same cord or cable.

8.1.10.3 BRANCH CIRCUIT CONDUCTORS

Branch circuits are the conductors between the last overcurrent device in an electrical system and the outlets, such as receptacles, lighting outlets, and outlets for electrical equipment wired directly into a circuit. Branch circuits for temporary wiring shall originate inside an approved panelboard or power outlet that is rated for the voltages and currents the system is expected to carry. As with feeders, branch circuit conductors can be contained within multiconductor cord or cable assemblies.

8.1.10.4 NONMETALLIC SHEATHED CABLE

Nonmetallic sheathed cable shall be used as allowed by the NEC and as follows:

1. Along studs, joists, or similar supports closely following the building finish or running boards when 7 ft 8 in. or more above the floor

2. When firmly attached to each cabinet, box, fitting, or fixture by means of a cable clamp.

Nonmetallic sheathed cable shall not be used where precluded by the NEC as follows:

1. As portable extension cords

2. Lying on the ground subject to any type of traffic

3. Where subject to frequent flexing

4. As service entrance cable.

See Figure 8-1 for a detailed illustration of installing temporary wiring methods. NOTE: The 1996 NEC does not permit open wiring or conductors except as allowed in NEC Section 305-4(b) and (c) Exceptions.

Figure 8-1. Cables, cable assemblies, or multiconductor cords can be used for temporary wiring systems under certain conditions of use.

8.2 USING ASSURED EQUIPMENT GROUNDING CONDUCTOR PROGRAM

Where GFCI devices are not used ( See Section 2.7), the employer shall establish and implement an assured equipment grounding conductor program on construction sites covering all cord sets, receptacles that are not a part of the building or structure, and equipment connected by cord and plug that are available for use or used by employees. This program shall comply with the following minimum requirements:

1. A written description of the program, including the specific procedures adopted by the employer, shall be available at the job site for inspection.

2. The employer shall designate one or more competent persons to implement the program.

3. Each cord set, attachment cap, plug and receptacle of cord sets, and any equipment connected by cord and plug, except cord sets and receptacles that are fixed and not exposed to damage, shall be visually inspected before each day's use for external defects such as deformed or missing pins or insulation damage and for indications of possible internal damage. Equipment found damaged or defective shall not be used until repaired.

4. The following tests shall be performed on all cord sets, receptacles that are not a part of the permanent wiring of the building or structure, and cord-and-plug connected equipment required to be grounded:

a. All equipment grounding conductors shall be tested for continuity and shall be electrically continuous.

b. Each receptacle and attachment plug shall be tested for correct attachment of the equipment grounding con-ductor. The equipment grounding conductor shall be connected to its proper terminal.

5. All required tests shall be performed:

a. Before first use

b. Before equipment is returned to service following any repairs

c. Where there is evidence of damage.

d. At intervals not to exceed 3 months, except that cord sets and receptacles which are fixed and not exposed to damage shall be tested at intervals not exceeding 6 months.

6. The employer shall not make available or permit the use by employees of any equipment that has not met the requirements of this section.

7. Tests performed as required in this section shall be recorded. This test shall identify each receptacle, cord set, and cord-and-plug-connected equipment that passed the test and shall indicate the last date it was tested or the interval for which it was tested. This record shall be kept by means of logs, color coding, or other effective means and shall be maintained until replaced by a more current record. The record shall be made available on the job site for inspection.

For further information, reference NEC Section 305-6 and 29 CFR 1926.404(b) and Figure 8-2.

Figure 8-2. An assured equipment grounding program may be used if approved by authority having jurisdiction.

8.3 PORTABLE ELECTRICAL TOOLS AND EQUIPMENT

The electrical preventive maintenance (EPM) program should include the essential ingredients of Chapter 17 of NFPA 70B, Portable Electrical Tools and Equipment, and ANSI/UL 45, Portable Electric Tools. This includes employee training, maintenance, cord and attachment plug care, extension cords, major overhauls, and leakage current testing.