Residential electrical installation - Protection against overvoltages and lightning
From Electrical Installation Guide
The choice of Surge Protective Devices as well as their installation rules are described in chapter Overvoltage protection.
The three following main rules must be respected in particular:
1. It is imperative that the three lengths of cable used for the installation of the surge arrester each be less than 50 cm i.e.:
- the live conductors connected to the isolating switch
- from the isolating switch to the surge protective device
- from the surge protective device to the main distribution board (MDB) earth bar (not to be confused with the main protective-earth (PE) conductor or the main earth terminal for the installation). The MDB earth bar must obviously be located in the same cabinet as the surge protective device.
2. It is necessary to use an isolating switch of a type recommended by the manufacturer of the surge protective device.
3. In the interest of a good continuity of supply it is recommended that the circuit breaker be of the time-delayed or selective type.
