GEC Sizing Calculator

The GEC is the conductor that connects the service equipment grounding terminal to the grounding electrode system (ground rods, water pipes, CEE, etc.). It provides a path to earth for fault currents and lightning.

Yes, but aluminum GEC cannot be in direct contact with earth or masonry per NEC 250.64(A). Aluminum requires larger sizes and proper protection where exposed.

Per NEC 250.64(C), the GEC must be installed in one continuous length without a splice or joint, except: (1) splicing is permitted by irreversible compression connectors or exothermic welding; (2) busbars may be used; (3) the GEC may connect to specific equipment as permitted in 250.64(D). In practice, use exothermic welding (Cadweld) for underground splices and compression connectors for above-ground connections. Standard wire nuts are NEVER acceptable for GEC connections.

Per NEC 250.64(B), the GEC must be protected where subject to physical damage. If a #6 AWG or smaller GEC is exposed, it must be enclosed in rigid metallic conduit (RMC), intermediate metallic conduit (IMC), rigid PVC, electrical metallic tubing (EMT), or cable armor. A #4 AWG or larger GEC may be exposed if it is securely fastened to the surface and is not subject to physical damage. When the GEC runs through metallic conduit, both ends of the conduit must be bonded to the GEC to prevent inductive heating.

These three grounding components serve different purposes. The GEC (Grounding Electrode Conductor) connects service equipment to the earth electrode system — it handles lightning and voltage stabilization. The EGC (Equipment Grounding Conductor) runs with circuit conductors and provides a low-impedance fault return path to trip breakers — it provides personnel protection. The Main Bonding Jumper connects the neutral bus to the ground bus at the service equipment, establishing the neutral-to-ground bond that makes the EGC fault clearing system work. All three are required at every service entrance.