Circuit Breaker

A circuit breaker is a resettable safety switch in your electrical panel that automatically trips (turns off) when it detects excessive current, protecting wires and equipment from overheating and fire. Unlike fuses, which must be replaced after they blow, circuit breakers can simply be reset.

In a solar installation, a dedicated solar circuit breaker is installed in your main service panel (or subpanel) to connect the solar system to your home’s electrical system. This breaker is typically sized at 20–40 amps for residential systems, depending on the inverter’s output. The NEC’s “120% rule” limits the combined amperage of the main breaker and the solar breaker — for a 200-amp main panel, the solar breaker cannot exceed 40 amps. If your panel doesn’t have space for an additional breaker or can’t accommodate the solar breaker under the 120% rule, your installer may need to upgrade the panel or add a subpanel. Some solar components also use DC-rated breakers, which are specifically designed to safely interrupt direct current — standard AC breakers cannot be used for DC circuits because DC arcs behave differently.