Construction and placement of resistances

Resistances shall be made entirely of fire-resisting material and shall also be so constructed and maintained that no coil or other parts shall at any time become unduly heated, i.e., they shall not become so heated that a piece of paper placed in contact with any part of the resistance would readily ignite. All resistances, with the exception of a resistance for regulating purposes, shall be placed outside the enclosure and in a part of the building to which the public are not admitted.