Bonding jumpers for service raceways shall be used around impaired connections such as _____ .
a) concentric knockouts
b) eccentric knockouts
c) reducing washers
d) all of the above
See answer and applicable Code reference
The correct answer is: d) all of the above
Bonding requirements are outlined in Part V of Art. 250. As noted in Sec. 250.92(B), "Bonding jumpers meeting the requirments of this article shall be used around impaired connections, such as reducing washers or oversized, concentric, or eccentric knockouts. Standard locknuts or bushings shall not be the only means for the bonding required by this section but shall be permitted to be installed to make a mechanical connection of the raceway(s)."