Estimate equipment grounding conductor size from breaker size or fuse size, conductor material, circuit type, and wiring method. This calculator gives a planning estimate for copper or aluminum ground wire sizing.
Breaker size:
The calculator starts with the breaker or fuse size because equipment grounding conductor size is commonly selected from overcurrent protection size.
Material:
Copper and aluminum grounding conductors use different planning sizes.
Result:
The calculator returns an estimated minimum equipment grounding conductor size, plus supporting wire area and run information.
A ground wire size calculator helps estimate the equipment grounding conductor size for a circuit, feeder, subpanel, or equipment run.
It can help with branch circuits, subpanel feeders, equipment circuits, garage wiring, shed wiring, detached structures, conduit planning, and cable planning.
Your result shows estimated ground wire size, breaker size range, conductor material, approximate circular mils, approximate diameter, estimated wire length, estimated wire weight, and comparison scenarios.
Equipment grounding conductor size is commonly based on the breaker or fuse size protecting the circuit. Choose the conductor material, then use the required grounding conductor size for that overcurrent protection level.
Not always. The equipment grounding conductor may be smaller than the ungrounded conductors in many circuits, but final sizing depends on code and the specific installation.
No. An equipment grounding conductor bonds equipment and provides a fault path. A grounding electrode conductor connects the electrical system to grounding electrodes such as rods, plates, or concrete-encased electrodes.
No. This is a simplified planning tool. Always verify ground wire size, bonding, subpanel separation, raceway rules, conductor type, and local code requirements with a qualified electrician.