How Do You Bond a Neutral and Ground in a Main Panel?

How Do You Bond a Neutral and Ground in a Main Panel?

In the main service panel (the first panel where utility power enters the building), the neutral and ground are bonded together at a single point. This bond is made using a main bonding jumper — typically a green screw, a strap, or a wire that connects the neutral bus bar to the panel enclosure and the grounding electrode conductor. This connection is required by the Ontario Electrical Safety Code and is only made in the main service panel, never in subpanels.

Why the Bond Exists

The neutral-to-ground bond at the main panel establishes the system reference point for voltage. Without it, the neutral conductor would float and safety would be compromised. The bond also ensures that a fault on any metal part of the electrical system has a low-impedance path back to the source, which allows overcurrent devices to trip quickly.

Why Subpanels Must NOT Be Bonded

In a subpanel (any panel fed from another panel rather than directly from the utility), the neutral and ground must be separated. The neutral bus must be isolated from the panel enclosure. The ground is connected to the enclosure, but the neutral floats. Bonding a subpanel creates a parallel path for neutral current to travel back through the grounding conductor — a code violation and a shock hazard. Four-wire feeds (hot, hot, neutral, ground) are required for subpanels to maintain this separation.

EZSMART handles panel upgrades, subpanel installations, and service work across Ontario. Contact us if you are unsure about the bonding configuration in your electrical system.

Amir Azimipour

Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp