Q. When grounding the frames of metal-enclosed power switchgear, which of the following methods listed here is the only one that is permitted by the 2008 NEC?

  1. A 6 AWG equipment bonding jumper from a nearby effectively grounded steel column.
  2. A 6 AWG grounding electrode conductor connected to a driven ground rod adjacent to the equipment.
  3. GFPE protection (30mA trip setting).
  4. A properly sized equipment-grounding conductor.

Answer: D

Per a change in the 2008 edition of the Code [490.36], instead of the statement "frames of switchgear and control assemblies shall be grounded," it is clearly noted now that "frames of switchgear and control assemblies shall be connected to an equipment-grounding conductor, or where permitted, the grounded 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.