250.66: Grounding Electrode Conductor (GEC)

Source: NEC 2020

Sizing Grounding Electrode Conductors for Alternating-Current Systems.

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Service Conductor Size (Cu)Service Conductor Size (Al/Cu-Clad Al)GEC Size (Cu)GEC Size (Al/Cu-Clad Al)
2 or smaller1/0 or smaller86
1 or 1/02/0 or 3/064
2/0 or 3/04/0 or 250 kcmil42
Over 3/0 through 350 kcmilOver 250 through 500 kcmil21/0
Over 350 through 600 kcmilOver 500 through 900 kcmil1/03/0
Over 600 through 1100 kcmilOver 900 through 1750 kcmil2/04/0
Over 1100 kcmilOver 1750 kcmil3/0250 kcmil

Related NEC Tables

Table 250.122: Equipment Grounding (EGC)Table 250.102(C)(1): Bonding Jumper Sizing

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