MANUFACTURED WIRING SYSTEMS

70-641 (b) Transformer. The transformer shall be of the window type or shall be within a metal enclosure. (c) Supply Conductors. Supply conductors shall consist of hard or extra-hard usage-type cord containing an equipment grounding conductor. The cord shall not exceed 10 feet (3.05 m) in length. (d) Secondary Conductors. Secondary conductors shall not be more than 6 feet (1.83 m) long and shall be located where not subject to physical damage, and shall be insulated for the voltage of the circuit and be protected by continuous glass or other insulating sleeves or tubing. (e) Grounding. Transformers and attached noncurrent-carrying metal parts shall be grounded in the manner specified in Article 250. (f) Support. Portable indoor signs shall be held in place by not more than two open hooks attached to the transformer case.