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Churches are buildings of high cultural Type Part No.
value and places of public assembly.
Therefore, they must be equipped with DV ZP TNC 255 (TN-C system) 900 390
permanently effective lightning protec- DV ZP TT 255 (TT/TN-S system) 900 391
tion systems as described in chapter 18 DG M TT 275 (TT/TN-S system) 952 310
of Supplement 2 of the German DIN EN
62305-3 lightning protection standard. DG M TT 2P 275 (TT/TN-S system) 952 110
The IEC 62305-4 (EN 62305-4) lightning See Figure 9.24.2
protection standard describes how to
implement surge protection measures. DFL M 255 924 396
Moreover, the IEC 60364-1 (HD 60364-1) BXTU ML4 BD 0-180 (4 cores) * 920 349
standard requires that “property shall + BXT BAS base part + 920 300
be protected against damage as a con- CTRL
929 042
sequence of overvoltages such as those DGA G BNC + 106 329
+ angled fixing plate
originating from atmospheric events or
from switching” (section 131.6.2). * Check whether arrester is suited for the system parameters
Figure 9.24.1 shows an example of
the standard equipment of a church. The CTRL
circuit of the control line of the bell con- hymn M
troller is illustrated in detail in Figure board 3~
9.24.2.
If the separation distance s is maintained
between the down conductors / lightning display
current carrying parts and the cables in-
stalled in the steeple, flashover is not to
be expected, however electromagnetic bell
coupling may occur. The following meas- contr. M M
ures can be taken to minimise electro-
magnetic coupling: SS SEB
¨ Short cable lengths
¨ No / little loop formation Figure 9.24.1 Principle of external and internal lightning protection for a church with steeple
If these measures are not feasible, surge
protective devices must be installed. In addition to the systems described before, the pipe heating
system, electronic organ and sound system are also highly sus-
Lightning equipotential bonding ceptible to electromagnetic coupling.
A lightning protection system requires lightning equipotential In the example shown, a separate earthing conductor to the
bonding for metallic systems and all buried cables entering main earthing busbar is not required for type 2 surge protec-
the building. In case of churches, equipotential bonding must tive devices (230 V or 230/400 V) for power supply systems
always be established for the low-voltage supply and other since the first surge protective device is already earthed.
cables, if any (e.g. escape lighting).
1 control line NYY-J 10 x 2.5 mm 2
3 TN-S or TT system
Surge protection 5 7
The cables in the bell tower and nave such as the cables of the N Type Part No.
electric clock mechanism and the bell controller are frequently PE
long and / or form loops. These two systems are time synchro- DG S 275 952 070
nised via the DCF 77 signal.
If the electrical hymn board is not radio controlled, electro- ... DGP C S 952 030
magnetic coupling is to be expected. Figure 9.24.2 Example of surge protective devices for the bell controller

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