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7.5 Access to voltage transformers, fuses or links
WARNING
For ENA version: do not access the area behind or
alongside the switchgear when it is energised or
being energised.
WARNING
All the operations describeb must only be carried
out by qualified and skilled personnel with in-
depth knowledge of the apparatus. Only use fuses
indicated by ABB.
In order to have access to voltage transformers MV
removable fuses or links (if installed), make reference
to the following procedures, according to the panel
version:
ENA version
1. Apply earth to the circuit by moving the three-
position disconnector switch to the EARTH position
(see par. 7.3.3.) and closing the circuit-breaker.
Secure the earth by fitting a padlock onto the
opening push-button (Figure 108) of the circuit-
breaker before opening the test equipment access
cover.
Note: Electrical tripping of the circuit-breaker is
disabled when the three-position disconnector is in
the EARTH position.
2. Disengage key B (Figure 109)
3. Unlock VT cover - (key D) (Figure 110)
4. Remove screws and front cover (Figure 111)
5. Access to MV removable fuses or links (Figure
111). If replacing fuses / links, make sure the new
ones are installed correctly
WARNING
Make sure that the rated normal current value
of the fuses to be installed is the same as the
one indicated on the fuse-holder nameplate.
6. Re-mount the external cover and make sure that
the screws are fully tightened. It is not necessary
to overtighten screws using tools because firm
tightening by hand is sufficient
WARNING
In order to ensure internal arc protection, it
must be checked that the screws are fully
tightened.
7. Lock VT cover - key D (Figure 110)
8. Re-engage key B (Figure 109)
Figure 108: Securing of opening push-button.
1 Opening push button
2 Access cover
Figure 109: Disengage key B.
Figure 110: Unlock VT cover - key D.
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