ABB ACS580-04 - Metal Conduit; Power Cable Shield

This table shows examples of methods for wiring the drive. Refer to NFPA 70 (NEC)
along with state and local codes for the appropriate methods for your application.
NotesWiring method
Conduit - Metallic
1) 2)
Prefer symmetrical shielded VFD cable.
Electrical metallic tubing: Type EMT
Use separate conduit run for each motor.Rigid metal conduit: Type RMC
Do not run input power wiring and motor wiring in
the same conduit.
Liquid-tight flexible metal electrical conduit: Type
LFMC
Conduit - Non-metallic
2) 3)
Prefer symmetrical shielded VFD cable.
Liquid-tight flexible non-metallic conduit: Type LFNC
Use separate conduit run for each motor.
Do not run input power wiring and motor wiring in
the same conduit.
Wireways
2)
Prefer symmetrical shielded VFD cable.
Metallic
Separate motor wiring from input power wiring and
other low voltage wiring.
Do not run outputs of multiple drives parallel. Bundle
each cable (wiring) together and use separators
where possible.
Free air
2)
Prefer symmetrical shielded VFD cable.
Enclosures, air handlers, etc.
Allowed internally in enclosures when in accordance
with UL.
1)
Metallic conduit may be used as an additional ground path, provided this path is a solid path capable of handling
ground currents.
2)
See NFPA NFPA 70 (NEC), UL, and local codes for your application.
3)
Non-metallic conduit use underground is allowed; however, these installations inherently have an increased chance
for nuisance problems due to the potential for water/moisture in the conduit. Water/moisture in the conduit
increases the likelihood of VFD faults or warnings. Proper installation is required to make sure there is no intrusion
of water/moisture.
Metal conduit
Couple separate parts of a metal conduit together: bridge the joints with a ground
conductor bonded to the conduit on each side of the joint. Also bond the conduits to
the drive enclosure and motor frame. Use separate conduits for input power, motor,
brake resistor, and control wiring. Do not run motor wiring from more than one drive
in the same conduit.
￭ Power cable shield
If the cable shield is used as the sole protective earth (PE) conductor, make sure that
its conductivity agrees with the PE conductor requirements.
To effectively suppress radiated and conducted radio-frequency emissions, the cable
shield conductivity must be at least 1/10 of the phase conductor conductivity. The
requirements are easily met with a copper or aluminum shield. The minimum
requirement of the motor cable shield of the drive is shown below. It consists of a
concentric layer of copper wires with an open helix of copper tape or copper wire. The
better and tighter the shield, the lower the emission level and bearing currents.
Guidelines for planning the electrical installation 85