It is required that temporary wiring comply with all the requirements pertaining to permanent wiring unless specific exceptions are stated, which can be found in NEC Article 305,29 CFR 1910.305(a)(2), and 1926.405(a)(2).

The following codes and standards will aid in designing, installing, and inspecting temporary wiring methods and using portable electric hand tools.

1. Articles 230, 305, and 400 of the National Electrical Code (NEC)

2. 29 CFR 1910.305

3. 29 CFR 1926.405

4. Table 232-1 of the National Electrical Safety Code (ANSI/IEEE C2)

5. Chapter 17 of NFPA 7013, Electrical Equipment Maintenance

6. Part I, Chapter 3 of NFPA 70E, Standard for Electrical Safety Requirements for Employee Workplaces.

8.1 REQUIREMENTS AND INSTALLATION CONDITIONS OF USE

Temporary electrical installations shall be allowed during periods of construction, remodeling, maintenance, repair, or demolition of equipment or structures or for experiments and developmental work. However, such temporary installations are not substitutes for permanent installations and shall be removed as soon as the construction, remodeling, experiment, or other special need is completed. See NEC Section 305-3(d).

8.1.1 CONTACT PREVENTION

Except as modified in Article 305, temporary wiring shall meet all the requirements of the NEC for permanent wiring to prevent accidental contact by workers or equipment.

8.1.2 VERTICAL CLEARANCES

Vertical clearance of wires, conductors, and cables above ground shall meet the requirements of NEC Section 230-24(b) and NESC Table 232-1.¹

¹ See Appendix D, Reference Matrix.

8.1.3 WET LOCATIONS

Conductors with nonrated weather-proof insulation shall not be enclosed in metal raceways or used for wiring in tanks, penstocks, or tunnels. Receptacles used in damp or wet locations shall be approved for the purpose. When a receptacle is installed outdoors (outdoors is considered a wet location), it shall be contained in a weatherproof enclosure, the integrity of which would not be affected when an attachment plug is inserted.

All temporary lighting strings in outdoor or wet locations, such as tunnels, culverts, valve pits, outlets, and floating plants, shall consist of lamp sockets and connection plugs permanently molded to the hard service cord insulation.

8.1.4 SUPPORTS

Bare or open conductors shall be insulated from their supports. This requirement prevents arcing, sparking, or flash-over to grounded objects. Open wiring for temporary installations is only allowed as per NEC Section 305-4(b) and (c) Exceptions.

8.1.5 CONDUIT

Temporary wiring installed in conduit shall have bushings at all outlets and terminals to prevent abrasion and damage to the insulation.

8.1.6 LIGHTING

All lamps for general illumination should be protected from accidental contact or breakage. Metalcase sockets shall be grounded.

Temporary lights shall not be suspended by their electric cords unless cords and lights are designed for this means of suspension. Temporary lighting used in damp, wet, or hazardous areas shall be marked as suitable for use in those locations.

Portable electric lighting used in wet or other conductive locations (for example, drums, tanks, and vessels) shall be operated at 12V or less. However, 120-V lights may be used if protected by aground fault circuit interrupter (GFCI).

Receptales on construction sites shall not be installed on branch circuits that supply temporary lighting. [See NEC Section 305-4(d)]

8.1.7 CONFINED SPACES

When temporary wiring is used in tanks or other confined spaces, an approved disconnecting means (identified and marked) shall be provided at or near the entrance to such spaces for cutting off the power supply in emergencies.

Portable electric lighting used in confined wet or hazardous locations such as drums, tanks, vessels, and grease pits shall be operated at a maximum of 12 V, be intrinsically safe, or be protected by a GFC1 circuit.

8.1.8 EXPOSED SOCKETS AND BROKEN BULBS

Exposed empty light sockets and broken bulbs shall not be permitted. This rule is to protect personnel from accidentally contacting the live parts in the socket and being shocked.

8.1.9 GROUND FAULT PROTECTION FOR PERSONNEL

Temporary power to equipment used by personnel shall be protected by GFCI devices, where required, or included in an assured equipment grounding conductor program, where permissible. See NEC Section 305-6, 29 CFR 1926.404(a)(3)(b), Sections 2.7 and 8.3 for further information.