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Circuit Breaker Size Calculator

Formula

The formula to calculate the proper amperage size of a circuit breaker is:

$A = \frac{P}{V}$

Where:

(A) is the amperage the circuit breaker needs to be rated for (amps)
(P) is the adjusted power (wattage)
(V) is the source voltage (volts)

What is a Circuit Breaker?

A circuit breaker is a device that stops the flow of current in an electrical circuit if a certain current level is exceeded. For example, if a circuit breaker is rated for a current of 1000 amps, and the current reaches 1005, then the circuit breaker should cut off all current to the system.

Example Calculation

Let's assume the following values:

Adjusted Power (P) = 4800 watts
Source Voltage (V) = 240 volts

Using the formula:

$A = \frac{4800}{240} = 20 \text{ amps}$

The Circuit Breaker Size (A) is 20 amps.