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PowerFlex 700L Technical Data

20 Publication 20L-TD001A

Cable Recommendations

Cable Types Acceptable for 200-600 Volt Installations

A variety of cable types are acceptable for drive installations. For many installations, unshielded cable is adequate,

provided it can be separated from sensitive circuits. As an approximate guide, allow a spacing of 0.3 meters (1 foot) for

every 10 meters (32.8 feet) of length. In all cases, long parallel runs must be avoided. Do not use cable with an insulation

thickness less than or equal to 15 mils (0.4mm/0.015 in.). Use Copper wire only. Wire gauge requirements and

recommendations are based on 75°C (167°F). Do not reduce wire gauge when using higher temperature wire. See table

below.

Unshielded Cable

THHN, THWN or similar wire is acceptable for drive installation in dry environments provided adequate free air space

and/or conduit fill rates limits are provided. Do not use THHN or similarly coated wire in wet areas. Any wire chosen

must have a minimum insulation thickness of 15 mils (0.4mm/0.015 in.) and should not have large variations in insulation

concentricity.

Shielded Cable

Shielded cable contains all of the general benefits of multi-conductor cable with the added benefit of a copper braided

shield that can contain much of the noise generated by a typical AC drive. Strong consideration for shielded cable should

be given in installations with sensitive equipment such as weigh scales, capacitive proximity switches, and other devices

that may be affected by electrical noise in the distribution system. Applications with large numbers of drives in a similar

location, imposed EMC regulations or a high degree of communications/networking are also good candidates for shielded

cable.

Shielded cable may also help reduce shaft voltage and induced bearing currents for some applications. In addition, the

increased impedance of shielded cable may help extend the distance that the motor can be located from the drive without

the addition of motor protective devices such as terminator networks. Refer to “Reflected Wave” in Wiring and Grounding

Guidelines for Pulse Width Modulated (PWM) AC Drives, publication DRIVES-IN001.

Consideration should be given to all of the general specifications dictated by the environment of the installation, including

temperature, flexibility, moisture characteristics, and chemical resistance. In addition, a braided shield should be included

and be specified by the cable manufacturer as having coverage of at least 75%. An additional foil shield can greatly

improve noise containment.

A good example of recommended cable is Belden

29528-29532 (AWG-1 through AWG-410). This cable has 3 XLPE

insulated conductors plus ground with a spiral copper shield surrounded by a PVC jacket.

Other types of shielded cable are available, but the selection of these types may limit the allowable cable length.

Particularly, some of the newer cables twist 4 conductors of THHN wire and wrap them tightly with a foil shield. This

construction can greatly increase the cable charging current required and reduce the overall drive performance. These

cables are not recommended.

Armored Cable

Cable with continuous aluminum armor is often recommended in drive system applications or specific industries. It offers

most of the advantages of standard shielded cable and also combines considerable mechanical strength and resistance to

moisture. It can be installed in concealed and exposed manners and removes the requirement for conduit (EMT) in the

installation. It can also be directly buried or embedded in concrete.

Because noise containment can be affected by incidental grounding of the armor to building steel (see “Wire Types” in

Wiring and Grounding Guidelines for Pulse Width Modulated (PWM) AC Drives, publication DRIVES-IN001) when the

cable is mounted, it is recommended the armor cable have an overall PVC jacket.

Interlocked armor is acceptable for shorter cable runs, but continuous welded armor is preferred.

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