Article 527 - Temporary Installations
By Mike Holt, for EC&M Magazine
By following Article 527, you can avoid the permanent consequences of unsafe temporary installations.
James Bond has a license to kill. Sometimes, temporary installations look like something rigged up under that same license. While many of us think of the NEC as a standard that helps us ensure the safety of the end-user, it also helps us ensure the safety of all the trades working on any given project where temporary electrical installations are part of the picture.
When you think of the Authority Having Jurisdiction (AHJ), dont you usually think of the electrical inspector? The inspector isnt the only AHJ for a given job, especially while it is in progress and there is temporary power or light. The general contractor and OSHA can enforce temporary installation rules. So can the insurance providers of such parties as your company, the general contractor, other trades, and the property owner.
[527.1] The requirements of Article 527 apply to all temporary power and lighting installations, including power for construction, remodeling, maintenance, repair, demolitions, and decorative lighting. This article also applies when temporary installations are necessary during emergencies or for tests and experiments. All of the requirements of the NEC apply to temporary installations unless specifically modified in this article. Those modifications are very few.
Certain venues have additional requirements. Temporary installations for trade shows must comply with Article 518. Temporary installations for carnivals, circuses, fairs and similar events must comply with Article 525.
[527.3] Temporary installation rules do provide some savings in cost and time, compared to permanent rules. At one time, electricians would install temporary power or lighting under those looser Code requirements and installations would be temporary on a permanent basis. Thus, time constraints made their way into the NEC and are as follows:
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You must remove all temporary installations immediately upon the completion of the purpose for which they were installed.
Areas of Application
In 527.4, the NEC provides specific rules for each major area of application. This is really the meat of the Article. Whats especially useful about this arrangement of the NEC is you can refer to exactly what you are working on. For example, if you are providing a temporary branch circuit, you can refer to 527.4(C) and see what the requirements are. The NEC addresses these areas of application in a logical order, beginning with the service entrance:
[527.6] You must provide ground-fault protection for temporary wiring used for construction, remodeling, maintenance, repair or demolition of buildings, structures, equipment or similar activities.
All 125V, 15A, 20A, and 30A receptacles used for temporary power must have GFCI protection. You can provide GFCI protection via circuit breakers, receptacles, cord sets or other devices such as GFCI adapters incorporating listed GFCI protection (see Figure 4 un527-04 527-06A 01.cdr).
You must provide GFCI protection for receptacles that are part of the permanent wiring of the building and are used for temporary power (see Figure 5 un527-05 527-06A 02.cdr). Exception: You dont need to provide GFCI protection for receptacles located in industrial establishments where only qualified personnel are involved in maintenance and are following an Assured Equipment Grounding Conductor Program (AEGCP).
Receptacles rated other than 125V, 15A, 20A, or 30A that supply temporary power to equipment used by personnel during construction, remodeling, maintenance, repair or demolition of buildings, structures, equipment, or similar activities must comply with either GFCI protection or an AEGCP (see Figure 6 un527-06 527-06B.cdr). You can use GFCI protection and an AEGCP on the same job, if you want to-they are not mutually exclusive.
An AEGCP requires grounding tests of cord sets, receptacles and cord-and-plug-connected equipment. All equipment grounding conductors must be tested for continuity. Each receptacle and attachment plug must be tested for the correct attachment of the equipment grounding conductor. The results of these tests must be recorded and made available to the AHJ. The tests must be performed before:
For wiring over 600V, nominal, you must provide suitable fencing, barriers, or other effective means to limit access to only qualified personnel. Common sense and or the AHJ may require such guarding for lower voltages as well, based on job site conditions.
How can you sum up the requirements for temporary installations? The first rule is they must be truly temporary. Service entrances have no temporary allowances. Other applications allow you to use cords and cable assemblies rather than installing raceways, and they allow you to place splices outside of boxes. But, theres a trade-off. You must also provide the additional protection of a GFCI or AEGCP. In addition to satisfying the AHJ, you ensure your own safety when your temporary installation conforms to Article 527.
Copyright © 2002 Mike Holt Enterprises,Inc.