Chapter A General rules of electrical installation design

J20
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J - Protection against voltage surges in LV
1
Equipment to be
protected
2
Determine the
architecture of the
building
3
Risk level of
the impact of a
lightning strike
Choice of type of
surge arrester
Sensitive equipment: Building equipment:
Type 2
20 kA
Single
switchboard,
main
switchboard
Type 2
40 kA
Type 2
40 kA
Burglar alarm,
fire alarm,
access control,
video-surveillance, etc.
Type 1
25 kA
or
35 kA
+
Type 2
40 kA
Distribution
board
Type 2
20 kA
Schneider Electric - Electrical installation guide 2008
Automated heating or
air-conditioning,
lift, etc.
Dedicated
protection,
more than
30 m from a
switchboard
Note:
Type 1: very high discharge capacity surge arrester used with a lightning conductor with an impact level of and .
Type 2: surge arrester used in cascade behind a type 1 surge arrester or alone in zone and .
Fig. J33 : Sensitive equipment, Building equipment
4 Choosing a protection device
Type 2
8 kA