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Section 10
Layouts for installing surge arresters in a box
To respect the rule of the shortest possible wiring - L < 50 cm - the phases and
neutral should be directly connected to the disconnection circuit-breaker and the
earth link should be connected to the surge arrester's earth terminal (fig. 39).
Fig. 39 - example of a surge arrester installation layout for household applications
It is advisable to use this type of wiring in small installations (e.g. domestic).
Connection combs should be used as far as possible as they provide optimum
wiring.
The wiring layout shown in figure 40 is the most practical, especially for service
sector and industrial applications which regularly require maintenance or wiring
modifications.
For this purpose, the following is added:
A phase/neutral wiring distribution terminal block as close as possible to the
b
associated circuit breaker
An intermediate earth terminal block as close as possible to the surge arrester
b
The protection of sensitive equipment will be ensured from these terminal blocks.
The length of the general supply cables and earth cable will therefore no longer
make any difference.
Fig. 40 - example of shortest wiring for the service sector and industry
Installing surge arresters in
a box or cabinet
General installation
rules