John Astleford Jr., P.E., Astleford Inc., Stone Mountain, Ga., found this grounded conductor connection hanging outside an open junction box with no cover when he was checking an electric oven for widely varying temperatures. This was part of a branch circuit that was run to a wall-mounted oven that was supplied from a 120/240V, single-phase, three-wire system.
All of the wires were loose from each other and were making intermittent electrical contact. No wire nuts were used, and only a loose covering of vinyl electrical tape was wrapped around this terrible splice. The “hot” conductors were also twisted together in the same manner and were also covered with vinyl electrical tape. The junction box was located behind the wall-mounted oven, and no connectors or cable clamps were on the incoming and outgoing cables. The box was not properly grounded. The third grounded conductor in the photograph comes from a receptacle feeding an outlet box for a cord and plug connected 120V microwave oven that is a part of the equipment installation.
The equipment was grounded using a conductor that was grounded at the service entrance panelboard as permitted by old Section 250-60 as an exception when four conditions are met. John cited the following violations: Sections 370-4, all metal boxes shall be grounded in accordance with Article 250; 370-16 number of conductors in box; 370-17 conductors entering box shall be protected from abrasion; 370-18; 110-12(a) unused openings in boxes shall be effectively closed; and 110-14(b) improper electrical connections and splices.
Editor's Note: Section 250.140 in the 2002 NEC still permits use of the grounded conductor to also serve as an equipment grounding conductor for the frames of ranges and clothes dryers for existing branch-circuit installations only. New branch-circuit installations must comply with 250.134 and 250.138.