2-27
Figure 2-23.Circuit breaker with an operating handle.
Circuit breakers used for low power protection, such as 28-volt dc, 30 amperes, can be physically
small. With low power use, arc extinguishers are not required, and so are not used in the construction of
these circuit breakers. Figure 2-24 shows a low power circuit breaker of the push-button or push-pull
type. This circuit breaker has a thermal trip element (the bimetallic disk) and is nontrip-free. The push
button is the operating mechanism of this circuit breaker.