EGC Size Calculator (NEC 250.122(B))
Conductor Material
Copper
Aluminum
Original Ungrounded Conductor Size
14 AWG
12 AWG
10 AWG
8 AWG
6 AWG
4 AWG
3 AWG
2 AWG
1 AWG
1/0 AWG
2/0 AWG
3/0 AWG
4/0 AWG
250 kcmil
300 kcmil
350 kcmil
400 kcmil
500 kcmil
600 kcmil
750 kcmil
1000 kcmil
New Ungrounded Conductor Size
14 AWG
12 AWG
10 AWG
8 AWG
6 AWG
4 AWG
3 AWG
2 AWG
1 AWG
1/0 AWG
2/0 AWG
3/0 AWG
4/0 AWG
250 kcmil
300 kcmil
350 kcmil
400 kcmil
500 kcmil
600 kcmil
750 kcmil
1000 kcmil
Original EGC Size
14 AWG
12 AWG
10 AWG
8 AWG
6 AWG
4 AWG
3 AWG
2 AWG
1 AWG
1/0 AWG
2/0 AWG
3/0 AWG
4/0 AWG
250 kcmil
300 kcmil
350 kcmil
400 kcmil
500 kcmil
600 kcmil
750 kcmil
1000 kcmil
Calculate
NEC 250.122(B) Reference
When ungrounded conductors are increased in size to compensate for voltage drop,
the equipment grounding conductor (EGC) must be proportionally increased in circular mil area.
