4 Electrical Installation
4.1 Safety Instructions
See chapter 2 Safety for general safety instructions.
WARNING
INDUCED VOLTAGE!
Induced voltage from output motor cables from dierent
frequency converters that are run together can charge
equipment capacitors even with the equipment turned
o and locked out. Failure to run output motor cables
separately or use screened cables could result in death
or serious injury.
•
Run output motor cables separately, or
•
Use screened cables.
•
Simultaneously lock out all the frequency
converters.
WARNING
SHOCK HAZARD
The frequency converter can cause a DC current in the
PE conductor and hence result in death or serious injury.
•
When a residual current-operated protective
device (RCD) is used for protection against
electrical shock, only an RCD of Type B is
permitted on the supply side.
Failure to follow the recommendation means that the
RCD cannot provide the intended protection.
Overcurrent protection
•
Extra protective equipment such as short-circuit
protection or motor thermal protection between
frequency converter and motor is required for
applications with multiple motors.
•
Input fusing is required to provide short-circuit
and overcurrent protection. If fuses are not
factory-supplied, the installer must provide them.
See maximum fuse ratings in chapter 4.4 Fuses.
Wire type and ratings
•
All wiring must comply with local and national
regulations regarding cross-section and ambient
temperature requirements.
•
Power connection wire recommendation:
Minimum 75 °C rated copper wire.
See chapter 5 Specications for recommended wire sizes
and types.
4.1.1 General Notes on Cabling and Fusing
NOTICE
All cabling must comply with national and local
regulations on cable cross-sections, cable types, and
ambient temperature.
For protection of the frequency converter, use the
recommended fuses or install a unit with built-in fuses. For
recommended fuses, see chapter 4.4 Fuses. Always ensure
that proper fusing is made according to local regulation.
The mains connection is tted to the rst switch gear in
the mains circuit if this is included.
4.2 EMC Compliant Installation
Perform the following steps to support EMC-compliant
installation:
NOTICE
TWISTED SCREEN ENDS (PIGTAILS)
Twisted screen ends increase the screen impedance at
higher frequencies, which reduces the screen eect and
increases the leakage current. Avoid twisted screen ends.
•
Connect the screen to the enclosure at both ends
for use with:
- Relays.
- Control cables.
- A signal interface.
- Fieldbus.
- Brake.
If the ground path has high impedance or is
noisy or is carrying current, break the screen
connection on 1 end to avoid ground current
loops.
•
Use a metal mounting plate to convey the
currents back to the unit. Ensure good electrical
contact from the mounting plate through the
mounting screws to the frequency converter
chassis.
•
Use screened cables for motor output cables. An
alternative is unscreened motor cables within
metal conduit.
Electrical Installation Installation Guide
MG13B102 Danfoss A/S © 09/2015 All rights reserved. 25
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