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Miniature circuit breaker or switch shall be installed in front of SPD

Miniature circuit breaker or switch shall be installed in front of SPD
Q: Recently, I saw the wiring mode of the miniature circuit breaker installed in front of the surge protector. When it is connected in parallel with the power distribution, some are connected to the upper end of the circuit breaker (the miniature circuit breaker in front of the surge protector) and some are connected to the lower end (actually, I want to ask whether the surge protector is connected above or below the miniature circuit breaker.)
Ask where to connect?
A: in the lightning protection project, there are many disputes about the installation position and type selection of power arrester. 1. Installation principles
Theoretically, the primary lightning arrester (class B) shall be installed at the front end of the main incoming line air switch as far as possible. If the installation is inconvenient, it can also be installed at the rear end of the air switch. However, if there is a dual power switching device at the front end of the incoming line, it must be installed at the front end of the dual power switching device, so that the switching device can be protected (most of the dual power switching devices are mechanical and electronic control, and some are 232 and 485 Control Devices and 24-volt fire power supply. Once the lightning current passes through, it is very easy to be damaged). The reason is that the action time of the air switch (circuit breaker) is much longer than that of the lightning arrester. Once there is lightning current (overvoltage), the lightning arrester will act in advance before the action of the circuit breaker to discharge the overcurrent, so as to protect the circuit and its back-end electrical equipment.
2. Selection principle
Voltage switch type arrester shall be selected for class B arrester as far as possible, with large current capacity and small protection voltage up as far as possible.