A new term “supply-side bonding jumper” was added.

250.2 Definitions.

Bonding Jumper, Supply-Side. A conductor on the supply side or within a service or separately derived system to ensure the electrical conductivity between metal parts required to be electrically connected. (click here to see Fig. 5)

Analysis: Equipment bonding jumpers are used often in the NEC, although the manner in which they’re sized depends on the location (in the circuit) of the bonding jumper. Generally speaking, bonding conductors located downstream of an overcurrent device are sized in accordance with 250.122, based on the rating of the overcurrent device. Bonding conductors upstream of an overcurrent device, such as the supply side of a service or between a transformer and panelboard, are typically sized using Table 250.66 and the 12½% rule discussed in 250.102(C). This Code change not only provides a new term to more accurately describe an existing conductor, but also should help clear up the sizing confusion that many people have with bonding conductors.