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supporting tube with in-
tegrated HVI Conductor
ridge made of
heather or sod film for sealing the mast

bolted crossbar HVI Conductor installed under-
neath the roof up to the eaves

opening in the fascia board

Legend:
Down conductor
HVI Conductor HVI Conductor
(underneath installed in the
the roof) supporting tube
MEB Earth conductor
Test joint
Thatched roof

Figure 5.1.5.6 Schematic diagram and picture of the installation of the down conductor at the rafter
2
cording to the standard, a rolling sphere radius of 45 m must established by means of a flexible conductor H07V-K 1 x 16 mm .
be used for class of LPS III. In our example, the height of the The supporting tube is fixed at a special construction (crossbar)
air-termination system is 2.30 m. This height ensures that the and the down conductors are routed along the rafters of the
two chimneys at the ridge and the three new dormers on the roof construction underneath the battens (Figure 5.1.5.6). At
roof are located in the protected volume (Figure 5.1.5.5). the eaves, the HVI Conductors are led through the fascia board
(Figure 5.1.5.7).
A supporting tube made of GRP (glass-fibre reinforced plas- For architectural reasons, down conductors are installed in
tic) was chosen to elevate the air-termination system and to aluminium further down. The transition of the HVI Conductor
accept the insulated down conductors. The lower part of the to the uninsulated, bare down conductor near the earth-termi-
supporting tube is made of aluminium to ensure mechanical nation system and the installation of HVI Conductors are de-
stability. Unwanted sparking may occur in this section as a scribed in the relevant installation instructions. A sealing end
result of the induction effects on adjacent parts. To avoid this, is not required in this case.
no earthed parts or electrical equipment may be located at a
distance of 1 m around the aluminium tube. Therefore, e.g. ny-
lon tie wires should be used for ridges made of heather or sod. opening in the fascia board
Electrical isolation between air-termination systems and
down conductors and between the metal installations to be
protected and equipment of power supply and information HVI Conductor
technology systems in the structure requiring protection can
be achieved by maintaining a separation distance s between
these conductive parts. This separation distance must be de-
termined according to the IEC 62305-3 (EN 62305-3) standard.
The high-voltage-resistant, insulated HVI Conductor has an
equivalent separation distance of s = 0.75 m (air) or s = 1.50 m
(solid material). Figure 5.1.5.6 shows the arrangement of the
down conductor.
The HVI Conductor is installed in the supporting tube and con-
nected via a central earthing busbar. Equipotential bonding is Figure 5.1.5.7 HVI Conductor led through the fascia board

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