Grounding & Bonding Calculator
Sizes the equipment grounding conductor from the circuit's OCPD rating per Table 250.122 (with the adjustment required when ungrounded conductors are upsized for voltage drop), and the grounding electrode conductor from the service conductor size per Table 250.66.
What it calculates
- Equipment grounding conductor (EGC) size from OCPD amperage, copper or aluminum
- EGC upsizing when the circuit's ungrounded conductors were upsized beyond the minimum required
- Grounding electrode conductor (GEC) size from the service conductor size and electrode type
Typical inputs
- Circuit OCPD rating, or the service conductor size
- Conductor material
- Whether ungrounded conductors were upsized, and by how much
Frequently asked
Why does upsizing a circuit's hot conductors also affect the ground wire?
250.122(B) requires the EGC to be enlarged in proportion to the circular-mil area increase of the ungrounded conductors — an EGC sized only off the OCPD rating would otherwise be undersized relative to a fault path that needs to match a beefier hot conductor.
Autodesk and Revit are registered trademarks of Autodesk, Inc. SYMATEQ is not affiliated with, endorsed by, or sponsored by Autodesk, Inc. SYMATEQ Electrical Calculators is an independent add-in for Autodesk® Revit®. Calculations are engineering aids and do not replace review by a licensed professional engineer or confirmation with the authority having jurisdiction.