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radius of the
rolling sphere

radius of the
rolling sphere

Application Type Part No. Application Type Part No.
Lightning current arresters Lightning current arresters
TN system DB M 1 255 (2x) 961 120 TN-S system DB M 1 255 (4x) 961 120
DB M 1 255 961 120 DB M 1 255 (3x) 961 120
TT system TT system
DGP M 1 255 961 101 DGP M 1 255 961 101
Combined arresters Combined arresters
TN system DSH TN 255 941 200 TN-S system DSH TNS 255 941 400
TT system DSH TT 2P 255 941 110 TT system DSH TT 255 941 310
Figure 9.2.3 Outdoor lighting system in the form of a 230 V wall Figure 9.2.4 Outdoor lighting system in the form of a 3x 230/400 V
lamp in lightning protection zone 0 A with lightning lamp pole in lightning protection zone 0 A with light-
equipotential bonding at the entrance point into the ning equipotential bonding at the entrance point into
building the building

The recommended arrester types must be installed at the
transition from LPZ 0 A to 1 or from LPZ 0 B to 1.
Type 1 lightning current arresters must be provided at the
entrance point into the building for all outdoor lighting sys-
tems in LPZ 0 A . To determine this lightning protection zone,
the relevant rolling sphere is “rolled over” the outdoor light- radius of the
ing system from all possible directions. If the rolling sphere rolling sphere
touches the outdoor lighting system, it is located in LPZ 0 A
(Figures 9.2.3 and 9.2.4).

Before installing type 1 lightning current arresters, it has to be
checked whether an energy-coordinated type 2 surge arrester
is already installed in the distribution board which houses the
circuits of the outdoor lighting system. If this is not the case,
we recommend to install combined arresters at the transition
of the lightning protection zones.
Type 2 surge arresters must also be installed at the entrance Application Type Part No.
point into the building for all outdoor lighting systems in TN system DG M TN 275 952 200
LPZ 0 B (Figure 9.2.5).
TT system DG M TT 2P 275 952 110
Figure 9.2.5 Outdoor lighting system in the form of a 230 V wall
lamp in lightning protection zone 0 B

272 LIGHTNING PROTECTION GUIDE www.dehn-international.com