Relays and circuit breakers are devices used to stop currents flowing through circuits. The main difference between relay and circuit breaker is that relay is typically used as a switch in circuits with small currents from flowing in circuits.
A circuit breaker is a device used in an electrical panel that monitors and controls the number of amperes sent through the electrical wiring. Circuit breakers are provided in a variety of sizes. A circuit breaker is a mechanically operated electrical switch made to protect an electrical circuit from harm incurred by excess current from an overload or a short circuit.