2 Engineering
2.3 Cable cross-sections
DB1 variable frequency drive
11/20 MN040031EN
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2.3 Cable cross-sections
The mains cables and motor cables must be sized as required by local stan-
dards and by the load currents that will be involved.
The PE conductor’s cross-sectional area must be the same as the phase
conductors’ cross-sectional area. The connection terminals marked with
must be connected to the earth-current circuit.
A symmetrical, fully screened (360°), low-impedance motor cable must be
used. The length of the motor cable depends on the RFI class and the envi-
ronment.
For US installations, UL-listed cables (AWG) should be used exclusively.
These cables must have a temperature rating of 70 °C (158 °F), and will often
require installation inside a metal conduit (please consult the applicable local
standards).
2.4 Safety and switching
2.4.1 Disconnecting device
In the European Union, this disconnecting device must be one of the fol-
lowing devices in order to comply with European Directives as per standard
EN 60204-1, “Safety of machinery”:
•
An AC-23B utilization category disconnector (EN 60947-3)
•
A disconnector with an auxiliary contact that in all cases will disconnect
the load circuit before the disconnector’s main contacts open
(EN 60947-3)
•
A circuit-breaker designed to disconnect the circuit as per EN 60947-2
In all other regions, the applicable national and local safety regulations must
be complied with.
WARNING
The specified minimum PE conductor cross-sections (EN 61800-
5-1) must be maintained.
￫
The EMC requirements for the motor cables can be found in
section 3.4, “Correct EMC installation”, page 58.
￫
Install a manual disconnecting device between the mains con-
nection and the DB1 variable frequency drive. This disconnec-
ting device must be designed in such a way that it can be inter-
locked in its open position for installation and maintenance
work.
