Creative Compressor Repairs
Thanks go out to EC&M reader Michael Noll for sharing these interesting photos with us. It appears the original controller for this air compressor failed, and a new controller was jury rigged by placing it in a toolbox! While I give this installer credit for creativity, I doubt this is a Code-compliant installation. The toolbox enclosure for this motor controller certainly was not selected using Table 110.28. Toolboxes are not wiring methods recognized as suitable as specified in Sec. 110.8. Using the white wires as ungrounded conductors is permitted in cable assemblies, but Sec. 200.7(C)(1) requires reidentification of the white wires by using marking tape, paint, or other effective means at terminations and other locations where the conductors are visible to indicate their use as ungrounded conductors. The lack of support for the NM cables violates Sec. 334.30. The improperly secured metal extension ring violates Sec. 314.23(A). The lack of a cover for the metal boxes violates Sec. 314.25. The number of conductors in the metal box seems questionable as to whether it complies with the fill requirements of Sec. 314.16. Lastly, securing NM cable to the EMT violates Sec. 300.11(C).
A Down and Dirty Cable Installation
This was the wiring I found while troubleshooting some pole lights that had stopped working. The installer had run NM cables underground between the pole lights. NM cable was a bad choice of wiring methods to use for an underground installation. This type of cable is not designed to withstand the harsh conditions that can exist in underground installations, including moisture, fungus, frost heaves, and other damaging effects from being buried directly in the soil. While Sec. 334.12(B) does not specifically prohibit NM cable from being installed underground, Sec. 334.12(B)(4) does prohibit its installation in wet or damp locations, and the Art. 100 definition of a wet location includes installations underground and in concrete slabs, as well as locations subject to saturation with water or other liquids and in locations exposed to the weather. Even if the NM cable was some type of temporary installation, Sec. 590.2(A) states that all the requirements for permanent wiring apply to temporary installations unless Art. 590 specifically modifies those rules. Nothing in Art. 590 would allow NM cables to be installed underground for temporary installations. We had to inform the manager for this property that all the underground wiring for the pole lights needed to be replaced.
