Exposed elements of impedance heating systems shall be physically guarded, isolated, or thermally insulated with a _____ jacket to protect against contact by personnel in the area.
a) corrosion-resistant
b) waterproof
c) weatherproof
d) flame-retardant
See answer and applicable Code reference
The correct answer is: c) weatherproof
The requirements of Art. 426 apply to electrically energized heating systems such as fixed outdoor electric deicing and snow-melting equipment. As noted in Sec. 426.30 with regard to personnel protection, "Exposed elements of impedance heating systems shall be physically guarded, isolated, or thermally insualted with a weatherproof jacket to protect against contact by personnel in the area."