Furnace Circuit Breaker Size

The switch connects to the furnace inside a wiring box.

Furnace circuit breaker size. This will provide the necessary overload protection for the circuit wiring and internal furnace components that are part of that 30 amp circuit. The size of a breaker is determined by the amp draw. As circuit breakers cbs and overcurrent protection devices ocpd are designed for 100 rated current i e. Difference between circuit breaker and isolator disconnector circuit breaker size calculation for continuous non contentious load.

However typically electric furnaces require a draw between 60 and 80 amps. The residential gas furnace needs power only to run the motor so it usually needs a 15a breaker if it doesn t share the circuit with other consumers in the home. The best thing you can do is check the nameplate on the furnance where you will find the power and breaker requirements for your specific unit. A single sheathed cable runs from the circuit breaker to a single pole light switch located next to the furnace.

A 30a circuit breaker can safely carry the exact 30a current but nec suggests 80 as a safe current limit as compared to the rated current. The furnace uses the power. The blower and control circuit for a modern gas furnace uses its own 110 to 125 volt circuit breaker. Because of the lower amperage rating of the 30 amp circuit of the new furnace the existing 60 amp circuit that will be connected to the 30 amp circuit should be changed to the 30 amp rating.