Q. Disregarding exceptions, which enclosure is limited to 30-foot (maximum) extensions beyond the equipment it supplements?

  1. Metallic wireways, only where limited to a maximum of 30 current-carrying conductors.
  2. Nonmetallic wireways, only where limited to a maximum 20% fill for all conductors.
  3. Busways, as long as the busway is not supplying and supporting flexible cords and cables.
  4. Auxiliary gutters.

Answer: D

As per 366.12 (Uses Not Permitted), “Auxiliary gutters shall not be used under the following conditions:
“(1) To enclose switches, overcurrent devices, appliances, or other similar equipment.
“(2) To extend a greater distance than 9 m (30 ft) beyond the equipment that it supplements.”

Note: The exception and FPN from this section of the Code are not listed here.

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 necexpert@aol.com.