Ecmweb 7755 Nec Illustrated Catastrophes 0915 Pr
Ecmweb 7755 Nec Illustrated Catastrophes 0915 Pr
Ecmweb 7755 Nec Illustrated Catastrophes 0915 Pr
Ecmweb 7755 Nec Illustrated Catastrophes 0915 Pr
Ecmweb 7755 Nec Illustrated Catastrophes 0915 Pr

Illustrated Catastrophes: Rogue Rooftop Receptacle

Sept. 16, 2015
More Code catastrophes uncovered and corrected in these faulty installations

Rogue Rooftop Receptacle

This installation violates Sec. 406.9(B)(1) of the Code. When installed in wet locations such as this rooftop, 15A or 20A receptacles must have an enclosure that is weatherproof — even when the attachment plug is inserted. An outlet box hood installed for this purpose must be listed and identified as “extra duty.” This enclosure does not have an “extra-duty” rated cover, and would only be weatherproof when the equipment is unplugged and the cover is closed. This installation is a perfect candidate for installation of a “bubble cover” in order to protect the receptacle and bring it into compliance. The Exception in Sec. 406.9(B)(1) permits a “weatherproof-when-closed” type of cover only if this area is subject to routine high-pressure spray washing, provided the cover is closed during the spray washing. In addition, 125V and 250V non-locking type receptacles are required to be listed as weather-resistant in wet locations.

Another concern I have is the possible lack of GFCI protection. Section 210.8(B)(3) requires this readily accessible rooftop receptacle to be provided with GFCI protection. This protection could be provided through the receptacle or a breaker or another GFCI device. Exception No. 2 would permit GFPE protection instead of GFCI protection if this receptacle was not readily accessible and was installed for snow melting, de-icing, or pipeline/vessel heating purposes.

We Don’t Support This Support

I’ve read Sec. 314.23 over and over, but I can’t find any wording that would justify the support methods used for this box. Liquidtight flexible metal conduit (LFMC) simply cannot be used as a supporting means for a box. Rigid metal conduit (RMC), on the other hand, could be used to support boxes if done correctly. Sec. 314.23(E) permits an enclosure not larger than 100 cu in. to be supported by RMC or intermediate metal conduit (IMC) where the conduits are threaded wrenchtight into the enclosure and secured within 3 ft of the enclosure or within 18 in. of the enclosure if both conduits enter on the same side of the enclosure. This installer used RMC on one side and LFMC on the other. This means that this box is essentially unsupported and can flop around. This could put strain on the conduit coming out of the roof and could cause the pipe to bend or break under the right conditions (e.g., heavy snowpack or high wind conditions). It also appears as though the LFMC is not supported correctly since Sec. 350.30(A) generally requires LMC to be securely fastened within 12 in. of each box, conduit body, or cabinet.
About the Author

Russ LeBlanc | Owner

Russ started in the electrical trade as an apprentice in 1985. He worked his way up to become a Journeyman Electrician and then eventually became a Master Electrician and Licensed Construction Supervisor. In 1999 Russ become an Electrical Instructor for The Peterson School of Engineering in Massachusetts where he developed his passion for teaching, and quickly became Department Head of Electrical Instruction. Russ has taught thousands of apprentices, electricians, engineers, inspectors, and other electrical professionals during his career as an instructor. He continues to provide electrical professionals with Electrical Code seminars, Arc-Flash Awareness training seminars and educational material through his LeBlanc Consulting Services in North Reading, MA whose specialty is educating electricians. He has been an active member of the NFPA Electrical Section and has authored hundreds of National Electrical Code proposals and comments which have become Code rules to improve the safety for the electrical industry. Russ is also an IAEI certified Electrical Inspector.

Please visit www.russleblanc.net for more information.

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