Electrical protection device against transient overvoltages, and installation using the same

摘要

The device has two branches (A, B), each comprising a varistor (20) to clip a surge voltage. A fuse (14) is connected in series with the varistors and is triggered in case of a short circuit of the varistors. The fuse has a trigger time-current operating curve in which a trigger time value is less than a trigger time value given for the same current value in an operation curve of a circuit-breaker, for each current value.