Regulating the Erection, Construction, Repair, Alteration, Location of all Electric Signs

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The wiring system supplying the primary and secondary current to trans- formers and associated equipment shall be by one of the recognized metallic wiring methods. (A) TRANSFORMERS. Transformers shall be of types with no exposed terminals, shall be marked with the maker's name, input rating and open circuit high ten- sion voltage. The marking shall be visible for inspection after installation. Where the transformer is located above the ceiling of the window, the high tension cable shall be in conduit and the conduit locked into the transformer enclosure. Except by special permission, transformers shall be of types where ratings do not exceed 30 milliamperes secondary or 450 volt ampere primary, nor exceed- ing 15,000 volts open circuit secondary with an additional 1000 volts for test. Where special permission has been obtained for installations exceeding 30 milliamperes, all tube electrodes shall be enclosed and door switches installed on all enclosures which, by opening, will break the primary circuit supply to the transformers and vacuum tube terminals. The capacity of an overcurrent device protecting one or more transformers shall be limited to 15 amperes at 125 volts. (B) GAS TUBING. The tubing shall be of such a length and design as not to cause a continuous overvoltage on the transformer. It shall be free from contact with flammable material and for circuit voltages exceeding 7500, from metal. It shall not be unduly exposed to mechanical injury. The supports for the tubing where needed, shall be of the insulated type of non - absorptive, non - combustible material and preferably adjustable. They shall maintain the tubing not less than 1/4 inch from metal parts and this spacing shall be maintained where the tubing passes through metal barriers, (C) ELECTRODES. The tube terminals shall comply with one of the following; 1. Project within an enclosure and be separated from grounded metal by - 27 -