Furnace Circuit Breaker Size

80 of breaker max single phase breaker size wire size based on copper thhn wire increase one size when using aluminum conductors at 115 volts at 230 volts 15 amp 14 1 380 2 760 20 amp 12 1 840 3 680 30 amp 10 seldom used on 115 voltage 5 520 40 amp 8 seldom used on 115 voltage 7 360 50 amp 6 seldom used on 115 voltage 9 200 60.

Furnace circuit breaker size.

The furnace uses the power. The switch connects to the furnace inside a wiring box. However typically electric furnaces require a draw between 60 and 80 amps. Difference between circuit breaker and isolator disconnector circuit breaker size calculation for continuous non contentious load.

A single sheathed cable runs from the circuit breaker to a single pole light switch located next to the furnace. By multiplying the volts by amps you will receive total wattage. The exact amps an electric furnace requires is solely based on the size of the furnace and its performance capabilities. 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 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. The blower and control circuit for a modern gas furnace uses its own 110 to 125 volt circuit breaker. This will provide the necessary overload protection for the circuit wiring and internal furnace components that are part of that 30 amp circuit.