Use as motor cabling and as
brake resistor cabling
Use as input power cablingCable type
Yes with motors up to 100 kW
(135 hp). A potential equalization
between the frames of motor and
driven equipment is required.
Yes
Shielded (Al/Cu shield or armor)
1)
four-conductor cable (three phase
conductors and a PE)
NoYes
WARNING!
If you use unshielded single-
core cables in an IT network,
make sure that the non-
conductive outer sheath
(jacket) of the cables have
good contact with a prop-
erly grounded conductive
surface. For example, install
the cables on a properly
grounded cable tray. Other-
wise voltage may become
present on the non-conduct-
ive outer sheath of the
cables, and there is even a
risk of an electric shock.
A single-core cable system: three
phase conductors and PE conduct-
or on cable tray
Preferable cable arrangement to
avoid voltage or current unbal-
ance between the phases
1)
Armor may act as an EMC shield, as long as it provides the same performance as a concentric EMC shield of a
shielded cable. To be effective at high frequencies, the shield conductivity must be at least 1/10 of the phase
conductor conductivity. The effectiveness of the shield can be evaluated based on the shield inductance, which
must be low and only slightly dependent on frequency. The requirements are easily met with a copper or aluminum
shield/armor. The cross-section of a steel shield must be ample and the shield helix must have a low gradient. A
galvanized steel shield has a better high-frequency conductivity than a non-galvanized steel shield.
Not allowed power cable types
Use as motor cabling and as
brake resistor cabling
Use as input power cablingCable type
NoNo
Symmetrical shielded cable with
individual shields for each phase
conductor
￭
Power cable shield
If the cable shield is used as the sole protective earth (PE) conductor, make sure that
its conductivity agrees with the PE conductor requirements.
To effectively suppress radiated and conducted radio-frequency emissions, the cable
shield conductivity must be at least 1/10 of the phase conductor conductivity. The
requirements are easily met with a copper or aluminum shield. The minimum
requirement of the motor cable shield of the drive is shown below. It consists of a
concentric layer of copper wires with an open helix of copper tape or copper wire. The
better and tighter the shield, the lower the emission level and bearing currents.
102 Guidelines for planning the electrical installation
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