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KNX
3 x 230/400 V SDB KNX
M
SEB
Type Part No.
DG M TNS 275 (TN-S system) 952 400
DG M TT 275 (TT system) 952 310
BT 24 925 001
Figure 9.10.7 Surge protective devices installed at the main distribution board and at the distribution board of the KNX system
Independent of the point of strike, surge protective devices al- Due to the high dielectric strength of the bus cable, it is unlike-
ways have to be installed at the distribution board of the KNX ly that short bus cables with isolated sensors (e.g. in a socket
system (Figures 9.10.6 and 9.10.7). outlet combination without earthed installation devices) are
destroyed. In this case, it is not necessary to install surge arrest-
ers directly at the bus devices (Figures 9.10.6 and 9.10.7).
316 LIGHTNING PROTECTION GUIDE www.dehn-international.com
