In short, moulded case circuit breaker (MCCB) is used in generally industrial or residential buildings as protection against short-circuit. For example, if a motor is 5 kilowatts, we often chose 10A of moulded case circuit breaker (MCCB). When there is a short-circuit in the motor or line, it can cut off the power timely.

For household appliances, refrigerators, washing machines etc., people often use residual current circuit breaker (RCCB) to protect safety and prevent the accident due to the current leakage.

ELCB is earth leakage circuit breaker, mainly for AC 50/60Hz, rated voltage 230V（single phase）/ 400V（three phases）, rated current up to 100A distribution network, used to prevent fire danger due to the damage of equipment insulation caused by the grounding fault current. It also can be used to protect the line from being overloaded and short-circuited as well as infrequent changeover of the line in normal situation.

When someone gets an electric shock or the leak current at the line exceeds the stipulated value, the circuit breaker could automatically break the power in 0.2S to protect the body and the equipment.