ABB ZX0 Manual For Installation And Operation page 29

Earthing of terminals on the voltage transformer terminal
board using earthing screws
Connections to earth potential can be established by means of
earthing screws on the terminals of the terminal board. Figure
2.3.5.2.2 illustrates this using the example of a voltage transformer
with one secondary winding.
Fig. 2.3.5.2.2: Earthing of terminals using earthing screws
A
a
Wiring the voltage transformers
The cable harnesses for wiring of the transformers are prepared
at the works and wired to the low voltage compartment. Wire the
transformers as follows.
Wire the secondary terminals and the earthing of
the voltage transformers in accordance with the
circuit diagrams.
Check that all terminal screws including the earthing screws are
tightly fastened.
Releasing the earthing screw on the 'N' terminal leads to poten-
tially lethal high voltage at the terminal when the voltage trans-
former is in operation!
Releasing the earthing screw on the 'N' terminal is only permis-
sible for test purposes on voltage transformers with de-energized
primary!
Always use the original earthing screws!
N
Connection to earth potential by
means of earthing screws
n
Manual ZX0 HB 600 en - Revision 05 | 29