The necessary safety measures to counteract
the effects of an internal arc fault must be
ensured in relation to the ceiling height. In
individual cases, this may require additional
operator protection measures on the switchgear
panels. These measures include:
1 Mounting a pressure relief duct (4/5 and 4/6)
on the top of the switchgear, with further
channels leading out of the switchgear room
in a form appropriate for the design of the
building. The shock wave and arc discharge
are channeled off in the duct.
2 Depending on the value of the system fault
current and the constraints of the switchroom
design the arc products are vented through
a top chimney of the arc duct and into the
switchroom. A typical arrangement is shown
in 4/7.
The rear wall of busbar compartment A, mounting
plate with shutters and horizontal partition and
form part of the internal partitioning.
The low voltage compartment for the secondary
equipment is completely protected from the high
voltage area thanks to its steel-sheet casing.
On the two ends of the switchboard, end covers
ensure good appearance and are mechanically
and thermally arc fault proof should such an
event occur.
Doors and rear walls as well as the end cover are
thoroughly cleaned and treated against corrosion.
Then doors and end cover receive high quality
powder coating of paint. Rear wall can be
painted by agreement. The finishing coat is in
the standard RAL 7035 colour (light grey - other
colours on request). Stoving completes the
painting procedure and provides protection from
impact and corrosion.
12
U N I G E A R Z V C
M E D I U M V O L T A G E P R O D U C T S
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4/5 Typical standard
arc duct arrangement
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4/6 Typical compact
arc duct arrangement
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4/5
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4/6