Table 250.102(C)(1) Grounded Conductor, Main Bonding Jumper, System Bonding Jumper, and Supply-Side Bonding Jumper for Alternating-Current Systems

The supply-side bonding jumper shall not be smaller than specified in Table 250.102(C)(1).
Where the ungrounded supply conductors are paralleled in two or more raceways or cables, and an individual supply-side bonding jumper is used for bonding these raceways or cables, the size of the supply-side bonding jumper for each raceway or cable shall be selected from Table 250.102(C)(1) based on the size of the ungrounded supply conductors in each raceway or cable. A single supply-side bonding jumper installed for bonding two or more raceways or cables shall be sized in accordance with 250.102(C)(1).
Informational Note No. 1: The term supply conductors includes ungrounded conductors that do not have overcurrent protection on their supply side and terminate at service equipment or the first disconnecting means of a separately derived system.
Informational Note No. 2: See Chapter 9, Table 8, for the circular mil area of conductors 18 AWG through 4/0 AWG.

Size of Largest Ungrounded Conductors or Equivalent Area for Parallel Conductors (AWG/kcmil) Size of Grounded Conductor or Bonding Jumper (AWG/kcmil)
Copper Aluminum or Copper-Clad Aluminum Copper Aluminum or Copper-Clad Aluminum
2 or smaller 1/0 or smaller 8 6
1 or 1/0 2/0 or 3/0 6 4
2/0 or 3/0 4/0 or 250 4 2
Over 3/0 through 350 Over 250 through 500 2 1/0
Over 350 through 600 Over 500 through 900 1/0 3/0
Over 600 through 1100 Over 900 through 1750 2/0 4/0
Over 1100 Over 1750 See Notes 1 and 2.