Some people often ask: Circuit breakers and fuses are also overvoltage protection.

If there is a lightning current passing through, won’t the circuit breaker and fuse trip, so the  surge protector  will not work?

The first thing to say is that the surge protector is connected in parallel in the power line, and the response speed of the circuit breaker is not the same level as that of the surge protector. The circuit breaker is at the second level, and the surge protector is at the nanosecond level. Yes, the surge protector also protects the circuit breaker.

The function of installing a circuit breaker (circuit breaker) in front of the surge protector is mostly to avoid fire accidents such as burning when the internal lightning protection components of the surge protector have a continuous (power frequency) short circuit fault.

In addition, considering the impact of overcurrent or ground fault that may occur on the operation of information system equipment when the surge protector degrades or terminates, installing a circuit breaker in front of the surge protector is a backup protection!

It is worth noting that the surge protector should be installed in front of the RCD (residual current protection switch). If the leakage current of the surge protector exceeds the operating current value set by the RCD, the surge protector will be disconnected from the power supply. Because the discharge current of the surge protector will be interpreted as a leakage current by the RCD and tripped by mistake, then the load power supply of the RCD will be cut off, which is undesirable for some users. Therefore, the surge protectors of B and C The protector must be fitted in front of the RCD.