FIELD GUIDE • UPDATED SEPTEMBER 2026
Grounding vs. Bonding Explained
Identify the conductor and connection before choosing a sizing rule.
Grounding and bonding are related but different. Bonding creates an effective low-impedance fault-current path between conductive parts. Grounding connects a system or equipment to ground through the grounding electrode system.
Field method
An equipment grounding conductor travels with a branch circuit or feeder and helps carry fault current back to the source. A grounding electrode conductor connects service or separately derived system equipment to the grounding electrode. Bonding jumpers connect metal parts or grounded conductors where required.
Before sizing anything, identify which conductor it is, whether it is on the supply side or load side of overcurrent protection, the system voltage, conductor material, service or feeder conductor size, and the overcurrent-device rating.
Common mistakes
Common mistakes include using the equipment-grounding table for a grounding electrode conductor, bonding neutral and ground downstream where separation is required, overlooking concentric knockout bonding rules, and treating earth as the normal fault-current path.
Start with NEC Article 250. Common paths include 250.122 for equipment grounding conductors, 250.66 for grounding electrode conductors, 250.102 for bonding jumpers, and 250.30 for separately derived systems.
This subject is installation-specific. Verify the adopted edition, service configuration, electrodes, utility requirements, listed equipment and AHJ interpretation.