Weidmüller PV DC COMBINER BOX, Operating Instructions Manual

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Installation
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Preparing aluminium conductors
– Aluminium conductors are only suitable for installation
sites that are free from humidity or aggressive atmos-
pheres.
– It is recommended to use bimetallic connectors.
– Use neutral grease (e.g. acidfree and alkalifree vaseline)
to protect the surface of the alumimium from oxidation.
As a well known characteristic aluminium forms a thin,
non-conductive layer of oxide as soon as it is exposed to
the air. This layer increases the contact resistance between
the aluminium conductor and the current bar of the terminal
which can lead to poor contact. As a precondition regard
the following steps to prepare the aluminium conductors:
► Scrape the stripped end of the conductor carefully, e.g.
with a knife, to remove the layer of oxide.
Do not use brushes, files or emery paper be -
cause particles of aluminium can be deposited
on other conductors.
► Coat the end of the conductor immediately with a neutral
grease, and connect it to the terminal immediately.
► Tighten the screws with the maximum permissible tight-
ening torque.
Repeat the above procedure each time after the
conductor has been disconnected and shall be
reconnected.
5.8 Connection of the grounding cable
The PV DC COMBINER BOX is designed without any me-
tallic mounting plate or similar. The enclosure is made of
GFRP (Glass Fiber Reinforced Polyester). Therefore the
unique ground connector is used for the surge protection.
Note that this cable must be connected to provide the cor-
rect operation of the surge protection device (SPD).
Protective conductors and other earthing conductors for
functional and protective purposes cannot generally be
considered as equipotential bonding dedicated for surge
and lightning protection.
According to the standard CLC-TS 50539-12, the cross
section of connecting conductors to SPDs on the DC side
of PV installations must be as it follows:
– Earthing conductors of SPDs Type I shall have a min-
imum cross section of 16 mm
2
copper or equivalent or
equal to the cross section of live connectors, if greater
than 16 mm
2
.
– Earthing conductors of SPDs Type II shall have a min-
imum cross section of 6 mm
2
copper or equivalent or
equal to the cross section of live connectors, if greater
than 6 mm
2
.
– The cross section of the connecting conductors from
the SPD to live conductors shall not be smaller than the
cross section of the live conductors of the associated
circuit.
To ensure that the live conductors of the PV installation can
withstand the surge current stress, the cumulated cross
section of these conductors should not be less than 6 mm
2
for SPD Type II and 16 mm
2
for SPD Type I.
Otherwise, if in the combiner box there is a specific ground -
ing terminal for this purpose, check the specifications on
the electrical diagram attached inside the product.
► Strip the conductor for 12.5 mm using an appropriate
tool.
► Verify with the electrical diagram attached in the combi-
ner box where to connect the cable (ground connector of
the SPD or a specific terminal for this purpose).
► In case the grunding cable is connected to a specific
terminal, connect the cable and tighten it with the screw
(2 ... 4.5 Nm).
► Verify the correct connection of the grounding cable to
the terminal.