Based on the 2005 NEC

by Mark Lamendola

National Electrical Code Top Ten Tips: Article 527, Temporary Installations

(This Article was discontinued with the 2008 NEC, so it appears only in the 2005 NEC and earlier.)

Arnold terminated villains and good guys alike, in his three Terminator movies. However, death and destruction should not be the role of your temporary installations--whether to your reputation or to people on the site. Here are 10 tips to make sure they aren't. 

  1. Note that the electrical inspector isn't the only Authority Having Jurisdiction (AHJ) for an installation, especially while it is in progress and there is temporary power or light. Others who can enforce the codes are the general contractor, OSHA, insurance providers, other trades, and the property owner [527.1].

  2. Article 527 applies to all temporary power and lighting installations, including power for construction, remodeling, maintenance, repair, demolitions, and decorative lighting. Follow it for those installations to prevent liability issues.

  3. Article 527 also applies when emergencies or testing require temporary installations. All of the requirements of the NEC apply to temporary installations unless specifically modified in Article 527. There aren't many such modifications.

  4. Specific venues have additional requirements--for example, trade shows must comply with Article 518.

  5. Don't install temporary wiring on a permanent basis. The time constraints are very clear, and they are legally enforceable in both civil and criminal courts. You must remove all temporary installations when you have completed the work that required installing them.

  6. In 527.4, you'll find specific rules for each major area of application. This is laid out very logically, so there is no mystery as to what is expected of you.

  7. You must install a temporary service per Article 230. That's right--the permanent rules apply, even to temporary services.

  8. Temporary feeder installations do not permit the use of open conductors, unless the individual open conductors are accessible only to qualified personnel. Don't abuse the "qualified personnel" idea. OSHA is very clear on what this means. If you can't document training for the specific tasks required, then you don't have qualified personnel. Just being an electrician, no matter how good, does not make someone a "qualified person."

  9. Contrary to established myth, all ungrounded circuit conductors must have a disconnecting means. That doesn't mean a taped-up splice. It means a switch, disconnect, or other device rated for the application. From a safety standpoint, it's even more important to have a highly visible, readily accessible disconnect for temporary installations than it is for permanent installations. The reason why is obvious to anyone walking through a construction site.

  10. Think of temporary installations as just that. The advantage of them is they generally allow you to use cords and cable assemblies rather than installing raceways, and they allow you to place splices outside of boxes. But, they don't allow you to to do that without a small price. You must also provide the additional protection of a GFCI and/or grounding program (e.g., AEGCP). Don't worry so much about satisfying the AHJ. Worry about ensuring your own safety by making your temporary installation conform to Article 527.