Churches

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05
APPLICATION PROPOSAL
External and Internal
Lightning Protection
for Churches
SV05/E/0112
External and Internal Lightning
Protection for Churches
Introduction
Steeples, due to their significant height, are at special risk of lightning strikes. Considering the cultural and historical value of churches and in view
of the fact that churches are places where a lot of
people are gathering frequently, the necessity of
lightning protection measures is quite obvious.
External lightning protection system
A lightning protection system Class III meets the
standard requirements for steeples and churches.
In some special cases, for example buildings of
cultural heritage or significant importance, additional measures in accordance with IEC 62305-2
(EN 62305-2) have to be carried out.
Nave
The nave’s own lightning protection system has to
be connected on the shortest possible route with
the down-conductor system of the steeple (Figure 1).
In case of a transept, the air-termination conductor along the ridge must have a down conductor
at both ends.
tors must be connected with the nave’s external
lightning protection system on the shortest route.
Down conductors basically have to be installed
outside at the steeple, an installation inside of it is
not allowed. Additionally the separation distance
“s” to metal components and electrical installations in the steeple (e.g. clock mechanisms, belfry,
etc.) and under the roof (e.g. air conditioning, ventilation and heating systems) must be maintained
by a corresponding arrangement of the external
lightning protection system. This required separation distance to be kept may become a problem
especially at the church clock. In this case, the risk
of dangerous sparking can be avoided by using
for example DEHNiso spacers to have the necessary distance between the down conductor and
the clock.
In new, reinforced concrete design churches, the
reinforcement steel may be used as down-conductor system if the steels are safely and conductively
interconnected. The reinforcement of pre-cast
concrete parts may be used as down-conductor
Steeples
Steeples up to a height of 20 m must be equipped
with a down conductor. If steeple and nave are
built together, this down conductor has to be connected on the shortest possible route with the
external lightning protection system of the nave
(Figure 2). In case the steeple down conductor coincides with a nave’s down conductor, a common
down conductor may be used here. At least two
down conductors are necessary in case of steeples
higher than 20 m and one of these down conduc-
Figure 1 External lightning protection system at the nave
Figure 2 Down-conductor system installed at the steeple
APPLICATION PROPOSAL 05
External and Internal Lightning Protection for Churches
Page 2
www.dehn.de
05
APPLICATION PROPOSAL
system, if there are connection
points for the continuous interconnection of the reinforcement.
Equipotential bonding
Purpose and intention of equipotential bonding is to avoid
potential differences between
different extraneous conductive parts. Equipotential bonding has to be implemented
carefully according to IEC
60364-4-41, 60364-5-54 and
60364-6. For lightning equipotential bonding, the minimum
cross section of the earth conductor between surge protective devices and equipotential
bonding has to be at least
16 mm2 Cu.
DV ZP TNC 255 (TN-C system)
DV ZP TT 255 (TT system)
Part No. 900 390
Part No. 900 391
DG M TT 275 (TT system)
Part No. 952 310
DG M TT 2P 275 (TT system)
Part No. 952 110
see figure 4
DFL M 255
Part No. 924 396
BXTU ML4 BD 0-180 (4 wires)* Part No. 920 349
+ BXT BAS
Part No. 920 300
CTR
DGA G BNC
+ fixing bracket
Part No. 929 042
Part No. 106 329
* use only if compatible with system parameters
CTR
hymn
display
mot
3~
Lightning and surge protection
for the power supply system
As churches shall be equipped
emergency call
with an external lightning
protection system, lightning
equipotential bonding also
has to be carried out inside the
bell
building by directly connecting
M M
control
the metal frame of the buildELS
SEB
ing, the metal installations and
the external conductive parts
with the lightning protection
system. Additionally, all incoming conductive power supply Figure 3 Principle of an external and internal lightning protection at a church nave and steeple
and information technology
systems have to be integrated
the terminal device is ≤ 5 m additional protective
into the lightning protection equipotential bonddevices are not necessary.
ing via lightning current arresters (e.g. walkway/
path lighting).
Another important measure is the surge protection of the electrical installation inside of the nave
Lightning equipotential bonding shall be impleand the steeple. For this purpose all wires of the
mented immediately at the entrance point of the
electric conductors leading into the steeple will
cables into the building. The main distribution
be protected by surge protective devices up in the
board of the power installation of a church is often
steeple as well as in the corresponding distribuin the sacristy. Lightning equipotential bonding of
tion board down in the steeple or in the sacritsty
the low-voltage consumer installation is carried
(Figure 3). Depending on the used control techout according to Figure 3 with the combined lightnique, either surge protective devices type DEHNning current and surge arrester DEHNventil (DV).
guard or BLITZDUCTOR XT may be installed here.
If the conductor length between DEHNventil and
APPLICATION PROPOSAL 05
External and Internal Lightning Protection for Churches
www.dehn.de
Page 3
External and Internal Lightning
Protection for Churches
motor-driven façade motion train 1
1
3
5
7
N
PE
control line
NYY-J 10 x 2.5 mm2
TN-S / TT system
...
DG S 275 Part No. 952 070
DGP C S Part No. 952 030
M
~
1
2
1
2
Figure 4 Installation of surge protective devices in the bell control
system/bell automation
Acoustic systems and other electrical equipment
such as organ, floor heating, light control systems,
hymn display, must be considered separately.
6 x DEHNguard DG S 275
Part No. 952 070
DG MOD 275
DEHNguard
DG MOD 275
DEHNguard
DG MOD 275
DEHNguard
DG MOD 275
DEHNguard
DG MOD 275
2 1 2 N
DEHNguard
DG MOD 275
2 1 2 N
DEHNguard
In the area near the distribution board for the
bell control system all incoming conductors will be
protected by surge protective devices. It has to be
minded that the earth terminal of the surge protective devices will be connected with the local
protective conductor (PE) of the distribution board
and not directly with the equipotential bonding
bar down in the steeple. One possible solution is
shown in Figures 4 and 5. The conductors for the
motor-driven façade motion train will be equally
protected. Here likewise all incoming conductors
will be equipped with DEHNguard surge protective devices (see Figure 6).
PE
DG MOD 275
DEHNguard
Figure 6 Example of how to use the surge protective devices for
the clock motor (up in the steeple) in a TNS system
DEHNguard
DG S 275
Part No. 952 070
Figure 5 Installation of surge protective devices in the bell control system / bell automation
APPLICATION PROPOSAL 05
External and Internal Lightning Protection for Churches
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www.dehn.de
05
APPLICATION PROPOSAL
APPLICATION PROPOSAL 05
External and Internal Lightning Protection for Churches
www.dehn.de
Page 5
DEHN + SÖHNE
GmbH + Co.KG.
Hans-Dehn-Str. 1
Postfach 1640
92306 Neumarkt
Germany
Tel: +49 9181 906-0
FAX: +49 9181 906-1333
www.dehn.de
info@dehn.de
Type designations of products mentioned in the application
proposal being at the same time registered trademarks are
not especially marked. So if there is no marking of  or ® this
does not mean that the type designation is a free trade name.
Neither it can be seen whether patents or utility models and
other intellectual and industrial property rights are available.
We reserve the right to introduce changes in performance,
configuration and technology, dimensions, weights and materials in the course of technical progress. The figures are shown
without obligation. Misprints, errors and omissions as well as
alterations expected. Reproduction in any form whatsoever is
forbidden without our authorisation.
Brochure No. SV05/E/0112
© DEHN + SÖHNE 2012
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