Main Bonding Jumper

Category: infrastructure

The physical connection inside the main service panel that links the neutral bus bar directly to the ground bus bar.

The main bonding jumper establishes the critical path back to the utility transformer. By bonding the neutral and ground wires together *exclusively* at the primary service disconnect, it ensures a low-impedance path exists to instantly trip the circuit breaker during a short-to-ground event.

Common Examples

• The green screw inside the primary panel functions as the main bonding jumper, establishing the official neutral-to-ground connection point.
• Sub-panels must never contain a main bonding jumper; keeping the neutral and ground lines isolated downstream blocks dangerous stray loop currents.