2-21
Figure 2-16.—Circuit breaker components.
The FRAME provides an insulated housing and is used to mount the circuit breaker components (fig.
2-17). The frame determines the physical size of the circuit breaker and the maximum allowable voltage
and current.
The OPERATING MECHANISM provides a means of opening and closing the breaker contacts
(turning, the circuit ON and OFF). The toggle mechanism shown in figure 2-17 is the quick-make,
quick-break type, which means the contacts snap open or closed quickly, regardless of how fast the
handle is moved. In addition to indicating whether the breaker is ON or OFF, the operating mechanism
handle indicates when the breaker has opened automatically (tripped) by moving to a position between
ON and OFF. To reset the circuit breaker, the handle must first be moved to the OFF position, and then to
the ON position.
