Originally Posted by
Justloadit
What happened here is that the surge arrester did its job, and self destructed by tripping the circuit breaker by becoming a short circuit .The misunderstanding of surge protectors, is that they work indefinitely, this is not the case, (what actually happens, is that the material of the surge arrester melts with the energy from the surge causing a short circuit, absorbing the energy as the protection of the surge). They are designed to absorb the excessive energy from the surge. Well when you concentrate that amount of energy into a device which is 25 to 30mm diameter and 5 to 6mm thick, you can not expect the device to survive. It will self destruct, which during the process cause the circuit breaker to trip and protect the load. With in this device there are special fuses, which when the disc is destroyed/Short Circuited, the internal fuses blow. This is so designed so that a fire is not created by the destroyed surge material.
One way round this is to have high current fuses in series with the surge arrester, which causes the circuit breaker to trip, and the fuses blow. Then have a voltage monitoring device, which is on the surge side of the fuse, controlling a contactor supplying the load. This will prevent the user from reconnecting the load, and would require an electrician to clear the problem.
The resaon that there is a Neutral to Earth surge arrester is precisely for the times when the Neutral is disconnected from the supply. The 3 phase loads on the supply could cause huge voltage variations between Neutral and the supply Lives.
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