Ecmweb Com Sites Ecmweb com Files Uploads 2013 02 2 21 13 Code Q A Fig1
Ecmweb Com Sites Ecmweb com Files Uploads 2013 02 2 21 13 Code Q A Fig1
Ecmweb Com Sites Ecmweb com Files Uploads 2013 02 2 21 13 Code Q A Fig1
Ecmweb Com Sites Ecmweb com Files Uploads 2013 02 2 21 13 Code Q A Fig1
Ecmweb Com Sites Ecmweb com Files Uploads 2013 02 2 21 13 Code Q A Fig1

Code Q&A: Receptacles on a Construction Site

Feb. 21, 2013
Your most pressing National Electrical Code (NEC) questions answered

Q. What are the Code rules regarding receptacles installed on construction sites?

A. All receptacles used for temporary installations must be of the grounding type, and the receptacle grounding terminal must be connected to an equipment grounding conductor in accordance with 250.146 and 406.4. On a construction site, receptacles aren't permitted to be placed on a branch circuit that supplies temporary lighting [590.4(D)(1)], as shown in the Figure. This requirement is necessary so that illumination is maintained, even when the receptacle's GFCI-protection device opens.

All 15A and 20A receptacles installed in a wet location of a construction site must be within an enclosure that's weatherproof when an attachment plug is inserted. For other than one- or two-family dwellings, the outlet box hood must be listed for "extra-duty" use if supported by grade, and all nonlocking-type 15A and 20A, 125V and 250V receptacles in a wet location must be listed as weather resistant [406.9(B)(1) and 590.4(D)(2)].

Exposed plastic surface material of weather-resistant receptacles must have UV resistance to ensure that deterioration from sunlight doesn't take place, or that it's minimal. In testing, receptacles are subjected to temperature cycling from very cold to very warm conditions, and then subjected to additional dielectric testing. The rapid transition from the cold to warm temperatures will change the relative humidity and moisture content on the device, and the dielectric test ensures that this won’t create a breakdown of the insulation properties.

About the Author

Mike Holt

Mike Holt is the owner of Mike Holt Enterprises (www.MikeHolt.com), one of the largest electrical publishers in the United States. He earned a master's degree in the Business Administration Program (MBA) from the University of Miami. He earned his reputation as a National Electrical Code (NEC) expert by working his way up through the electrical trade. Formally a construction editor for two different trade publications, Mike started his career as an apprentice electrician and eventually became a master electrician, an electrical inspector, a contractor, and an educator. Mike has taught more than 1,000 classes on 30 different electrical-related subjects — ranging from alarm installations to exam preparation and voltage drop calculations. He continues to produce seminars, videos, books, and online training for the trade as well as contribute monthly Code content to EC&M magazine.

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