What is the electrical symbol qf?

Circuit breaker. The English name of circuitbreaker is Circuit Breaker, which is stipulated in IEC6 1636- 1. QF is a combination of letters, q means Switchingdeviceforpowercircuit, and f means Protectiondevice, which means that the circuit breakers are together. Thomas Edison first described the circuit breaker in the patent application 1879. It is an electrical safety device, which can turn on, carry and turn off current under normal loop conditions, and its main function is to protect the circuit from risks caused by overcurrent and short circuit.