VD4/R - VD4/L - VD4/R-SEC - VD4/L-SEC - INSTALLATION AND OPERATING INSTRUCTIONS 24
7.3 Preliminary operations
Clean the insulating parts with clean dry rags.
Make sure that the upper and lower terminals are
clean and free of any deformation caused by
shocks received during transport or storage.
7.4 Installation of fixed circuit
breakers
The circuit breaker can be installed straight on the
floor or on supporting frames provided by the
customer (see fig. 8).
The areas on which the supporting frames or truck
(if provided) rest must be on the same plane to
avoid any risk of distortion in the breaker
structure.
A minimum degree of protection (IP2X) must be
guaranteed from the front towards live parts.
The apparatus can be fixed in the following ways:
by means of special expansion anchoring bolts
with M8 threaded hole if the apparatus is fixed
to a cement floor
by means of M8 bolts if the apparatus is fixed to
metal structures or to cement floors into which
special steel sections have been embedded.
Whatever the method used, the fixing surface
must be welllevelled and all the resting points
must be on the same horizontal plane.
7.5 Installation of circuit breakers
for ABB switchgear
UniSec switchgear. Special assembly operations
are not usually required.
However, consult the documentation of the
switchgear in question.
Figure 8
7.6 Power circuit connections
7.6.1 General recommendations
Make sure that the circuit breaker terminals are
clean and are free from any deformation caused
by shocks received during transport or storage.
Choose the conductor cross-sections to suit the
service and short-circuit current of the
installation.
Provide suitable supporting insulators near the
fixed circuitbreaker terminals or the monoblocs
of the cubicles, sized according to the
electrodynamic stress caused by the short-
circuit current of the installation.
The circuit breaker terminals are always
silver-plated. To clean them, use only dry
rags, soaked in a suitable solvent if
necessary.
NOTE. Never use a file or emery cloth!
7.6.2 Maximum dimensions of the connections
For fixed version VD4 circuit breakers, the
connections must be shaped and installed in
accordance with the indications given in the
overall dimensions and in compliance with the
distances indicated.
7.6.3 Surface treatment of the connections
The connections can be made of bare copper or
bare aluminium. However, it is always advisable to
silver-plate the contact surfaces.
The thickness of the surface treatment must be
even and regular.
7.6.4 Assembly of the connections
Make sure that the contact surfaces of the
connections are perfectly flat and without burrs,
traces of oxidation or deformities caused by
drilling or impact sustained.
Depending on the conductive material used and
the surface treatment given, the operations
indicated in the following table 1 must be carried
out on the surface contact of the conductor.
Table1
Bare copper
Clean with a fine file or emery cloth
surfaces
Copper or
silverplated
aluminium
Clean with a rough dry cloth
Only if there are traces of oxidation that are difficult to
shift, clean with ultra-fine grain emergy cloth and take
care not to remove the surface layer
Repeat the surface treatment if necessary
Bare
aluminium
Clean with a metal brush or emery cloth
Immediately smear neutral grease over the contact
surfaces
Insert a bi-metal copper-aluminium strip with beaded
surfaces between the aluminium connection and the
copper terminal (copper side touching the terminal,
aluminium side touching the connection)
—
7. Installation
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