Screened/armoured cables
The screen must be a low HF-impedance screen. This
is ensured by using a braided screen of copper, alu-
minium or iron. Screen armour intended for mechani-
cal protection, for example, is not suitable for an EMC-
correct installation. See also Use of
EMC-correct
cables
.
Extra protection with regard to indirect contact
ELCB relays, multiple protective earthing or earthing
can be used as extra protection, provided that local
safety regulations are complied with. In the case of an
earth fault, a DC content may develop in the faulty cur-
rent.
Never use ELCB relays, type A, since such relays are
not suitable for DC fault currents.
If ELCB relays are used, this must be:
•
Suitable for protecting equipment with a di-
rect current content (DC) in the faulty current
(3-phase bridge rectifier)
•
Suitable for power-up with short charging
current to earth
•
Suitable for a high leakage current
VLT
®
6000 HVAC Series
MG.61.B5.02 - VLT
®
is a registered Danfoss trademark
69
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