Q. A 60-foot metal pole supporting luminaires is found to be deficient with respect to the 2005 version of the NEC. The installation consists of the following: The interior of the pole is being used as a raceway. A properly sized handhole has been provided. A grounding terminal within the pole has been provided. The size of the branch-circuit equipment-grounding conductor, which also serves to bond the metal pole to the metal raceway supporting the branch circuit conductors, is 12 AWG. The branch circuit rating is 30A.

What could possibly be the deficiency in this particular installation?

  1. There is no raceway inside the pole.
  2. The pole does not feature a hinged base.
  3. There is a lack of vertical conductor support per 300.19.
  4. Improperly sized equipment grounding and bonding conductor.

Answer: D

Per 410.15(B)(5), the size of the equipment and bonding jumper shall be in accordance with 250.122. A 30A rated branch circuit requires a minimum size 10 AWG equipment-grounding conductor.

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.