Surge-Protective Device Conductor Length

The requirements for surge-protective devices (SPDs), 1kV or less, are outlined in Art. 285 of the 2011 NEC.

April 9, 2014

The conductors used to connect the surge-protective device to ground shall not be any longer than _____ and shall avoid unnecessary bends.

a) 6 inches
b) 12 inches
c) 18 inches
d) necessary

See answer and applicable Code reference

The correct answer is: d) necessary

The requirements for surge-protective devices (SPDs), 1kV or less, are outlined in Art. 285 of the 2011 NEC. As noted in Sec. 285.12, "The conductors used to connect the SPD (surge arrester or TVSS) to the line or bus and to ground shall not be any longer than necessary and shall avoid unnecessary bends."