Ecmweb 8639 Nec Illustrated Catastrophe Nov 2016 Pr
Ecmweb 8639 Nec Illustrated Catastrophe Nov 2016 Pr
Ecmweb 8639 Nec Illustrated Catastrophe Nov 2016 Pr
Ecmweb 8639 Nec Illustrated Catastrophe Nov 2016 Pr
Ecmweb 8639 Nec Illustrated Catastrophe Nov 2016 Pr

Illustrated Catastrophes: Stop Making Waves

Nov. 18, 2016
More Code catastrophes uncovered and corrected in these faulty installations

All references are based on the 2014 edition of the NEC.

Stop Making Waves

At first glance, I thought this was an installation of flexible cord. However, upon closer examination, I realized this was actually a failed PVC pipe run. The installer did not install expansion fittings anywhere along this run. As a result, we end up with this failed and precariously hanging installation. These pipes are in danger of falling right onto the pedestrians walking below! The pipes have also separated at several couplings and at some of the box connectors. Water can now enter directly into the pipes and boxes, which exposes the conductors and connections to an increased possibility of water damage and corrosion.

These problems may have been avoided if the installer had properly installed expansion fittings as required by Sec. 300.7(B) and Sec. 352.44. The length change caused by thermal expansion and contraction of this pipe run certainly exceeded ¼ in. between the securely mounted boxes. When this happens, Sec. 352.44 specifies that expansion fittings must be used to accommodate this change in length and to help prevent the pipe run from self-destructing. Once the pipe starts to bend and twist from expansion and contraction, it’s only a matter of time before some clips snap off, and the self destruction snowballs into a disaster.

Like the Sword of Damocles

This luminaire is dangerously dangling by its wires and putting the people below it in harm’s way. There are other problems as well, but let’s focus on the luminaire first. It is no longer securely supported, as required by Sec. 410.30(A), and should be removed from service. The broken support knuckle will also allow water to enter directly into the fixture, which could cause it to short circuit and trip the breaker. This would most likely knock out all of the lighting in this area.

I also question the support methods used for the box attached at the end of the pipe. Section 314.23(F) generally requires boxes supporting luminaires to be supported by two conduits threaded into the box, with the conduits being secured within 18 in. of the box. Under very specific conditions, Exception No. 2 does permit one unbroken length of RMC or IMC to support a box used for luminaire support. However, this installation does not follow those specific rules. This entire pipe and fixture assembly is screwed into a box cover that is just not designed to handle the weight, leverage, and torque that could be applied by this installation.

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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