Wiring a Subpanel (4-Wire System)

Modern NEC code requires all subpanels to be fed with a 4-wire system: two hot wires, one neutral, and one dedicated equipment grounding conductor (EGC).

Separate Neutral & Ground

Unlike the main service panel, the neutral and ground bus bars must not be bonded in a subpanel. The neutral bar must remain isolated to prevent returning current from traveling on the grounding system.

Routing Heavy Feeder Cables?

Subpanel feeder lines (like 2/0 SER) are rigid and difficult to secure. Check out our parametric heavy-duty cable cleats. Customize the exact diameter for your SER cable and 3D print in PETG.