How Do You Size A Circuit Breaker?
The size of a circuit breaker you need to run electrical appliances and equipment depends on a number of factors. Circuit breakers operate as heat switches. When too much current runs through a circuit because of faulty electrical equipment or an overload in the circuit, the heat in the circuit exceeds the breaker ‘s load rating and it trips, shutting off the electrical power. Proper sizing eliminates overloads and insures safe electrical operation. Recognize that a circuit breaker is usually sized to operate at no more than 80 percent of its rated capacity. For example, a circuit breaker rated at 100 amps should only be installed in applications where a maximum of 80 amps is required. Circuit breakers are tested in controlled environments under ideal conditions. In most field applications, conditions are less than ideal, and factors such as ambient temperature, the number of circuit breakers in the panel, ventilation and other environmental conditions all affect the circuit breaker’s
