Insulation jacket1
Helix of copper tape or copper wire2
Copper wire shield3
Inner insulation4
Cable core5
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 cross-sectional area of the protective earth conductor must be
determined in a manner which produces a conductance equivalent to that which results
from the application of this table.
Minimum cross-sectional area of the corresponding
protective earth conductor
S
p
(mm
2
)
Cross-sectional area of the phase conductors
S (mm
2
)
S
1)
S ≤ 16
1616 < S ≤ 35
S/235 < S
1)
For the minimum conductor size in IEC installations, refer to Additional grounding requirements – IEC.
If the protective earth conductor is not part of the input power cable or input power
cable enclosure, the minimum permitted cross-sectional area is:
• 2.5 mm
2
if the conductor is mechanically protected,
or
• 4 mm
2
if the conductor is not mechanically protected. If the equipment is
cord-connected, the protective earth conductor must be the last conductor to be
interrupted if there is a failure in the strain relief mechanism.
86 Guidelines for planning the electrical installation
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