Sizing Equipment Grounding Conductors for Motor Circuits

Section 250.122 of the 2011 NEC spells out the requirements for sizing equipment grounding conductors.

May 28, 2014

Equipment grounding conductors for motor branch circuits shall be sized in accordance with Table 250.122, based on the rating of the _____ device.

a) motor overload
b) motor over-temperature
c) branch circuit short-circuit and ground-fault protective
d) feeder overcurrent protection

See answer and applicable Code reference

The correct answer is: c) branch circuit short-circuit and ground-fault protective

Section 250.122 of the 2011 NEC spells out the requirements for sizing equipment grounding conductors. Equipment grounding conductors for motor circuits shall be sized in accordance with 250.122(D)(1) or (D)(2). As noted in 250.122(D)(1), "The equipment grounding conductor size shall not be smaller than determined by 250.122(A) based on the rating of the branch-circuit short-circuit and ground fault protective device."