Circuit Breakers vs Switches: Can It be Interchanged?

Circuit breakers and switches are crucial for the safety in homes and industry. For industrial purposes, these devices need to be able to handle a higher capacity compared to a residential setting. But can circuit breaker be used as switch? Before going into that, let us first identify the difference between the two.

Circuit Breaker

A circuit breaker is a safety device used to prevent damage to motors and wiring. It does its job when the current flowing through the electrical circuit exceeds its design limit. It happens by removing the current from a circuit when unsafe circumstances arise. A circuit breaker automatically does this and shuts off the power immediately. In this way it works as an automatic service protection device. This is what makes the circuit breaker different from a switch.

Switch

A switch controls the flow of the electrical current within a circuit. It is used to inhibit or initiate the flow of the current. It manually cuts and reconnects the power from an electrical supply by creating or closing an air insulation gap between two conduction points. A switch is designed to power on and off.

The Difference

Circuit breakers break and switches switch. These differences are very important to consider in understanding their safety and practicality. Circuit breaker is not to be used as a switch due to issues of endurance. Switches are designed for use in multiple times of operations. It is meant to endure many times of turning on and off. Circuit breakers are not meant for nearly the same amount of operations as switches. Cycling a circuit breaker on and off multiple times will result in its eventual failure. However, some circuit breakers are rated for switching duty for lighting circuits, such as those applied in 120V 277V fluorescent lighting circuits (marked SWD or HID). SWD means Switching Duty while HID signifies High Intensity Discharge lighting. The UL489 Standard for MCBs states that SWD circuit breakers can be rated up to 20A, no more. HID breakers are rated up to 50A.

It is quite obvious by now that though they share a similar function on a basic level, they still are two different entities. It may work more effectively as safe switches, but they are not switches. They are not interchangeable. That being the case, circuit breaker as a switch is not recommended. 

Meanwhile, another question can be raised from this. Can switches be used in place of circuit breakers? Since switches are not designed to detect and interrupt an overload or faulty conditions, it would likely melt or burst into flames. Using a switch in replacement of the circuit breaker causes more problems. Switches switch and circuit breakers break. Don’t get confused with that.