What do the numbers on top of each circuit breaker represent?

The numbers on top of each circuit breaker indicate the maximum current load that the breaker can safely handle, typically measured in amps. This rating is crucial for ensuring that the circuit functions correctly and safely. Each circuit breaker is designed to protect electrical circuits from overloads and short circuits by trip-switching when the current exceeds this specified load. By knowing the amp rating, users can determine whether the breaker is suitable for the particular application and whether it will adequately protect the wiring and connected devices from potential damage.

Understanding this ensures that the electrical system remains safe, as using a breaker with a rating too low for the current can lead to nuisance tripping, while a breaker rated too high may not adequately protect the circuit from overloads. The other options do not pertain to the purpose of the rating on circuit breakers; for example, time before they fail or voltage ratings are not represented numerically in the same way, and the physical size of the breaker is not related to its amp load rating.