Life expectancy for molded case circuit breakers in the industry is generally expected to be about 30 years, given favorable environment and regular maintenance. Required maintenance, especially for older breakers, includes annual exercising—OFF, ON, TRIP, RESET, ON.

They are commonly used in low and medium-voltage applications and can handle higher levels of current than Miniature Circuit Breakers (MCBs). MCCBs typically have a rated current of 10 amps to 2,500 amps, and a breaking capacity of up to 200 kA.

Molded Case Circuit Breaker Function Molded case circuit breakers are primarily designed to protect electrical systems and equipment from overloads, short circuits, and other potentially damaging conditions. They do this by automatically disconnecting the circuit when it detects an overcurrent or fault in the system.

Sometimes called a “power” breaker, an Insulated Case Circuit Breaker is similar to a molded case breaker, but Is built on a frame inside an “insulated” molded plastic case. They are tested to the same UL489 standard as molded case circuit breakers.