Your Westinghouse circuit breakers are designed to trip when there is an overload or similar problem in the electrical system. If you run a hair dryer and an air conditioner on the same circuit, for example, there is too much of a power draw on that circuit. Too much power is a hazard, and the circuit breaker trips to cut the power before an electrical fire or other damage can result.
If the circuit breaker did not trip, the overload would most likely result in a fire. Electricity generates heat as it flows through the system. The normal amount of heat created does not pose a danger to your home or appliances, but when there is too much demand for power, the extra electricity causes the system to heat up even more. Once there is enough heat to melt insulation or ignite nearby materials, a serious fire hazard exists. The Westinghouse circuit breaker is made to cut off the electricity before a dangerous amount of heat is generated.