Rockwell Automation Allen-Bradley 1305-AA02A, Installation Instructions Manual

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Practices 4-13
together further reduces the antenna effects. Refer to Avoiding Loops in
Wiring on page 4-13 .
Figure 4.11 Avoiding Loops in Wiring
Conduit
Magnetic steel conduit is preferred. This type of conduit provides the best
magnetic shielding. However not all applications allow the use of magnetic
steel conduit. Stainless steel or PVC may be required. Conduit other than
magnetic steel will not provide the same level of shielding for magnetic
fields induced by the motor and input power currents.
Conduit must be installed so as to provide a continuous electrical path
through the conduit itself. This path can become important in the
containment of high frequency noise.
To avoid nicking, use caution when pulling the wire. Insulation damage can
occur when nylon coated wiring such as THHN or THWN is pulled through
conduit, particularly 90º bends. Nicking can significantly reduce or remove
the insulation. Use great care when pulling nylon coated. Do not use water
based lubricants with nylon coated wire such as THHN.
Do not route more than 3 sets of motor cables in one conduit. Maintain the
proper fill rates per the applicable electrical codes.
Do not rely on the conduit as the ground return for a short circuit. Route a
separate ground wire inside the conduit with the motor or input power
wires.
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