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No. in Fig. 9.13.1 and 2 Protection for… Surge protective device Part No.
Three-phase TN-S system DEHNventil DV M TNS 255 951 400
Three-phase TT system DEHNventil DV M TT 255 951 310
Three-phase TN-S system DEHNguard DG M TNS 275 952 400
Three-phase TT system DEHNguard DG M TT 275 952 310
230 V supply DEHNrail DR M 2P 255 953 200
24 V d.c. supply DEHNrail DR M 2P 30 953 201
BLITZDUCTOR XT BXT ML2 B 180 920 211
PROFIBUS
+ BXT BAS base part 920 300
BLITZDUCTOR XT BXT ML2 BE HFS 5 920 270
PROFIBUS
+ BXT BAS base part 920 300
BLITZDUCTOR XT BXT ML4 BD EX 24 920 381
PROFIBUS in hazardous area + BXT BAS EX base part 920 301
or DEHNpipe DPI MD EX 24 M 2 929 960
Table 9.13.1 Lightning current and surge arresters for intrinsically safe PROFIBUS PA, PROFIBUS FMS and DP
Building with external lightning protection system If lightning equipotential bonding, surge protection and exter-
If a building is equipped with an external lightning protec- nal lightning protection measures are properly implemented,
tion system, lightning equipotential bonding is required. To they reduce failure in case of direct lightning strikes to a mini-
this end, the earth-termination system is connected to pipes, mum.
metal installations and earthed parts of the power supply and
information technology systems. In addition, all power supply Building without external lightning protection
and information technology cables entering and leaving the system
structure are connected to the earth-termination system via If no external lightning protection system is installed, the bus
lightning current arresters (Figures 9.13.1 and 9.13.2). devices must be protected by surge arresters. In this case,
lightning current arresters for power supply and information
In addition to lightning equipotential bonding, surge protec- technology lines do not have to be installed (arresters 1 and 4
tion measures must be taken to protect electrical installations are not required).
and systems.
332 LIGHTNING PROTECTION GUIDE www.dehn-international.com
