Selecting the power cables
￭ General guidelines
Select the input power and motor cables according to local regulations.
• Current: Select a cable capable of carrying the maximum load current.
• Temperature: For an IEC installation, select a cable rated for at least 70 °C (158 °F)
maximum permissible temperature of conductor in continuous use. For North America,
select a cable rated for at least 75 °C (167 °F).
• Voltage: 600 V AC cable is accepted for up to 500 V AC. 750 V AC cable is accepted
for up to 600 V AC. 1000 V AC cable is accepted for up to 690 V AC.
To comply with the EMC requirements of the CE mark, use one of the preferred cable
types. See Preferred power cable types (page 88).
Symmetrical shielded cable reduces electromagnetic emission of the whole drive system
as well as the stress on motor insulation, bearing currents and wear.
Metal conduit reduces electromagnetic emission of the whole drive system.
The protective conductor must always have an adequate conductivity.
Unless local wiring regulations state otherwise, the cross-sectional area of the protective
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 conductor can either 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 conductor related
to the phase conductor size according to IEC/UL 61800-5-1 when the phase conductor
and the protective conductor are made of the same metal. If this is not so, the
cross-sectional area of the protective grounding conductor shall 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 corres-
ponding protective conductor
S
p
(mm
2
)
Cross-sectional area of the phase conduct-
ors
S (mm
2
)
S
1)
S ≤ 16
1616 < S ≤ 35
S/235 < S
1)
To comply with standard IEC/EN 61800-5-1 (UL 61800-5-1)
• use a protective earth conductor with a minimum cross-sectional area of 10 mm
2
Cu or 16 mm
2
Al (as an
alternative when aluminum cables are permitted),
or
Guidelines for planning the electrical installation 87
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