Illustrated Catastrophes, November 2010

Illustrated Catastrophes, November 2010

As usual, never consider the following commentary associated with these photos as a formal interpretation of the National Electrical Code (NEC). Without criticizing anyone or any product, the following scenarios present us with serious safety questions.

Twisted and Turned

This conduit is located at the entry of a tunnel and shows where proper support was not considered during design or installation. Article 352 covers rigid polyvinyl chloride conduit (PVC), which is defined as “a rigid nonmetallic conduit (RNC) of circular cross section, with integral or associated couplings, connectors, and fittings for the installation of electrical conductors and cables.” Section 352.30 outlines the approved methods of securing and supporting this type of conduit. Basically, this type of conduit shall be installed as a complete system (as outlined in 300.18) and shall be fastened to allow for movement due to thermal expansion or contraction. More specifically, “PVC conduit shall be securely fastened and supported in accordance with 352.30(A) and (B) or permitted to be unsupported in accordance with 352.30(C).” As noted in 352.30(A), “PVC conduit shall be securely fastened within 900 mm (3 ft) of each outlet box, junction box, device box, conduit body, or other conduit
termination. Conduit listed for securing at other than 900 mm (3 ft) shall be permitted to be installed in accordance with the listing.” As noted in the photo, this conduit system was clearly not installed with these requirements in mind.

Floating Free

This grounding electrode conductor (GEC) termination is located at the base of a wood utility pole. Someone thought this mechanical ground clamp was the perfect choice to secure the GEC to the ½-in. × 8-ft ground rod. However, the GEC barely makes any contact with the connection, thus not ensuring proper continuity.

Section 250.70 of the NEC covers the proper methods of grounding and bonding conductor connections to electrodes. It states, “The grounding or bonding conductor shall be connected to the grounding electrode by exothermic welding, listed lugs, listed pressure connectors, listed clamps, or other listed means. Connections depending on solder cannot be used. Ground clamps shall be listed for the materials of the grounding electrode and the grounding electrode conductor and, where used on a pipe, rod, or other buried electrodes, must also be listed for direct soil burial or concrete encasement. Not more than one conductor is allowed to be connected to the grounding electrode by a single clamp or fitting unless the clamp or fitting is listed for multiple conductors.” The grounding electrode conductor should have been installed on the opposite side of the connector, in the V-shaped groove of the fitting.

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