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82 Guidelines for planning the electrical installation
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.
Cross-sectional area of the phase conductors
S (mm
S ≤ 16
16 < S ≤ 35
35 < S
1) For the minimum conductor size in IEC installations, refer to
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
•
2.5 mm
if the conductor is mechanically protected,
or
2
•
4 mm
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.
Additional grounding requirements – IEC
￭
This section gives grounding requirements according to standard IEC/EN 61800-5-1.
Because the normal touch current of the drive is more than 3.5 mA AC or 10 mA DC:
•
the minimum size of the protective earth conductor must comply with the local safety
regulations for high protective earth conductor current equipment, and
•
you must use one of these connection methods:
1.
a fixed connection and:
•
a protective earth conductor with a minimum cross-sectional area of 10 mm
Cu or 16 mm
or
•
a second protective earth conductor of the same cross-sectional area as the
original protective earth conductor,
or
•
a device that automatically disconnects the supply if the protective earth
conductor is damaged.
2.
a connection with an industrial connector according to IEC 60309 and a minimum
protective earth conductor cross-section of 2.5 mm
power cable. Sufficient strain relief must be provided.
If the protective earth conductor is routed through a plug and socket, or similar means of
disconnection, it must not be possible to disconnect it unless power is simultaneously
removed.
Note: You can use power cable shields as grounding conductors only when their conductivity
is sufficient.
Additional grounding requirements – UL (NEC)
￭
This section gives grounding requirements according to standard UL 61800-5-1.
2
)
2
Al (as an alternative when aluminum cables are permitted),
Minimum cross-sectional area of the corresponding
protective earth conductor
S
p
Additional grounding requirements –
2
as part of a multi-conductor
2
(mm
)
1)
S
16
S/2
IEC.
2
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