For a portable or mobile sign, which is cord- and plug-connected, what is required to protect personnel who may touch or contact the sign?

  1. A 12 AWG equipment grounding conductor installed external to the supply cord.
  2. A 12 AWG equipment grounding conductor that is an integral part of the supply cord.
  3. A single driven ground rod bonded to the metallic enclosure of the sign with a 12 AWG equipment bonding jumper.
  4. A factory-installed ground-fault circuit-interrupter, which is an integral part of the attachment plug, or a factory-installed ground-fault circuit-interrupter located in the supply cord, within 12 in. of the attachment plug

Answer: D

NEC Art. 600 focuses on electric signs and outline lighting. More specifically, 600.10 outlines the requirements for portable or mobile signs. As per 600.10(C)(2), "Portable or mobile signs shall be provided with factory-installed ground-fault circuit-interrupter protection for personnel. The ground-fault circuit-interrupter shall be an integral part of the attachment plug or shall be located in the power-supply cord within 300 mm (12 in.) of the attachment plug.

Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at