8 • vacon Safety
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1.3 Earthing and earth fault protection
The Vacon NXL frequency converter must always be earthed with an earthing conductor connected to
the earthing terminal .
The earth leakage current of Vacon NX_ exceeds 3.5mA AC. According to EN61800-5-1, one or more
of the following conditions for the associated protective circuit shall be satisfied:
a. The protective conductor shall have a cross-sectional area of at least 10 mm
2
Cu or 16 mm
2
Al,
through its total run.
b. Where the protective conductor has a cross-sectional area of less than 10 mm
2
Cu or 16 mm
2
Al, a
second protective conductor of at least the same cross-sectional area shall be provided up to a
point where the protective conductor has a cross-sectional area not less than 10 mm
2
Cu or 16
mm
2
Al.
c. Automatic disconnection of the supply in case of loss of continuity of the protective conductor. See
chapter 6.
The cross-sectional area of every protective earthing conductor which does not form part of the
supply cable or cable enclosure shall, in any case, be not less than:
- 2,5mm2 if mechanical protection is provided or
- 4mm2 if mechanical protection is not provided.
The earth fault protection inside the frequency converter protects only the converter itself against
earth faults in the motor or the motor cable. It is not intended for personal safety.
Due to the high capacitive currents present in the frequency converter, fault current protective
switches may not function properly.
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