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down-conductor

Figure 5.1.8.13 Isolated air-termination system with DEHNiso Combi Figure 5.1.9.1 Installation of the down conductor on a steeple

More detailed information on the application of DEHNiso each end of the air-termination conductor along the transverse
Combi can be found in brochure DS151/E and in installation ridge must be equipped with a down conductor.
instructions No. 1475.
The methods described above can be combined with each Steeple
other as required to adapt the isolated air-termination system Steeples up to a height of 20 m must be equipped with a down
to the local conditions (Figures 5.1.8.10 to 5.1.8.13). conductor. If the steeple and the nave are joined, this down
conductor must be connected to the external lightning pro-
tection system of the nave along the shortest possible route
5.1.9 Air-termination system for steeples and (Figure 5.1.9.1). If the down conductor of the steeple crosses
churches a down conductor of the nave, a common down conductor
External lightning protection system can be used at this point. According to section 18.3 of Supple-
ment 2 of the German DIN EN 62305-3 standard, steeples with
According to section 18.1 of Supplement 2 of the German a height of more than 20 m must be provided with at least two
DIN EN 62305-3 standard, a lightning protection system ac- down conductors. At least one of these down conductors must
cording to class of LPS III meets the standard requirements be connected with the external lightning protection system of
for churches and steeples. In individual cases, for example in the nave along the shortest possible route.
case of structures of great cultural importance, a separate risk Down conductors on steeples must be routed to the ground
analysis must be carried out in accordance with IEC 62305-2 along the outer surface of the steeple. Installation inside
(EN 62305-2). the steeple is not allowed (Supplement 2 of the German
DIN EN 62305-3 standard). Furthermore, the separation dis-
Nave tance s from metal parts and electrical installations in the stee-
According to section 18.5 of Supplement 2 of the German ple (e.g. clock mechanisms, belfry) and underneath the roof
DIN EN 62305-3 standard, the nave must be equipped with (e.g. air-conditioning, ventilation and heating systems) must
a separate lightning protection system and, if a steeple is at- be maintained by a suitable arrangement of the external light-
tached, this system must be connected with a down conductor ning protection system. The necessary separation distance can
of the steeple along the shortest possible route. In the transept, be a problem especially at the church clock. In this case, the

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