Grounding Electrode Calculator

Size grounding electrodes and conductors per NEC 250

Ground Rod Estimation

Enter if known from fall-of-potential test

Grounding Requirements

Grounding Electrode Conductor --
Ground Rods Required --
Estimated Resistance (single rod) --
NEC Resistance Limit 25 Ω
Bonding Jumper Size --

NEC 250.66 - GEC Sizing

Service Conductor (Cu) GEC Copper GEC Aluminum
2 AWG or smaller8 AWG6 AWG
1 AWG - 1/0 AWG6 AWG4 AWG
2/0 - 3/0 AWG4 AWG2 AWG
Over 3/0 - 350 kcmil2 AWG1/0 AWG
Over 350 - 600 kcmil1/0 AWG3/0 AWG
Over 600 - 1100 kcmil2/0 AWG4/0 AWG