Table of Contents
Advertisement
Not allowed power cable types
Cable type
Symmetrical shielded cable with in-
dividual 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.
1
1
Insulation jacket
2
Helix of copper tape or copper wire
3
Copper wire shield
4
Inner insulation
5
Cable core
Grounding requirements
This section gives general requirements for grounding the drive. When you plan the grounding
of the drive, obey all the applicable national and local regulations.
The conductivity of the protective earth conductor(s) must be sufficient.
Unless local wiring regulations state otherwise, the cross-sectional area of the protective
earth conductor must agree with the conditions that require automatic disconnection of the
supply required in 411.3.2 of IEC 60364-4-41:2005 and be capable of withstanding the
prospective fault current during the disconnection time of the protective device. The
cross-sectional area of the protective earth conductor must be selected from the table below
or calculated according to 543.1 of IEC 60364-5-54.
This table shows the minimum cross-sectional area of the protective earth conductor related
to the phase conductor size according to IEC/UL 61800-5-1 when the phase conductor(s)
and the protective earth conductor are made of the same metal. If this is not so, the
Use as input power cabling
No
PE
Guidelines for planning the electrical installation 81
Use as motor cabling
No
2
3
4
5
Advertisement
Table of Contents
