VFD Cable Termination Guide

7/28/2019 VFD Cable Termination Guide

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Unarmored Variable FrequencyDrive (VFD) Cable Termination Guide

A Step-by-Step Look atthe Connection/Terminationof Unarmored VFD CablesBe Certain with Belden


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Terminating Unarmored Variable Frequency Drive (VFD) CablesFoil-Braid or Copper-Tape Shield Constructions

This Belden VFD Cable Termination Guide takesa step-by-step approach to the connection/termination o unarmored VFD cables with either

oil-braid or copper-tape shield constructions.The instructions cover the termination o thecables in external and sel -contained enclosures,at the motor junction box or using analternative method.

VFD Cable InstallationLocation Considerations

It is advisable to maintain as much separationas possible between noise-susceptible cablesand VFD cables a minimum o one oot orshielded instrumentation cables and three eet

or unshielded instrumentation cables. I thetwo types o cable must lie close to each other,it is best to minimize the amount o parallelruns between them, limiting these stretchesto 10 eet or less to reduce the likelihood o radiated noise pickup. Also, i the two types o cables must cross, it is pre erable to cross themperpendicularly at a single point.

As you use this step-by-step VFD CableTermination Guide, please note the re erencesto the drive or motor manu acturersrecommendations. You should be amiliar withthe manu acturers termination guidelinesas well. I you have specifc questions on theinstructions given within this guide, pleasecontact Belden Technical Support at 1.800.BELDEN.1 (1.800.235.3361).

Belden VFD Cablesare designed forquick and easytermination.

Three StrandedTC Circuit Conductorswith XLPE Insulation

Overall DuofoilShield + 85%TC Braid plus fullsize TC Drain Wire

Three Stranded TCCircuit Conductorswith XLPE Insulation

Two Spiral CopperTape Shields(100% Coverage)

One Full-sized InsulatedGround (same AWG asCircuit Conductors)

Three SymmetricalBC Grounds (full size)

One 16 AWG Shielded SignalPair for Brake with Drain Wire

Overall DuofoilShield + 85%TC Braid plus fullsize TC Drain Wire

Original Design Original Design with Signal PairOriginal Symmetrical Design

One Full-sized Insulated Ground(same AWG as Circuit Conductors)

Three StrandedTC Circuit Conductors

with XLPE Insulation

Beldens Variable Frequency Drive (VFD) Cable Offering

See VFD Cable Matrix (page 3) or additional in ormation.

2


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Original 3 16-2 Yes1 -

Full-sizedInsulated

Overall 100%Duofoil + 85%

TC Braid

Yes Yes Yes Yes Yes Yes Yes Yes Yes

OriginalSymmetrical 3 1-4/0 Yes

1 - Full-sizedSegmented

Into3 - Bare CUSymmetrical

Dual SpiralOverlappingCopper Tape

(100%Coverage)

Yes Yes Yes Yes Yes Yes Yes Yes

Originalwith Brake/Signal Pair

316-10

(16 AWGSignal Pair)

Yes1 -

Full-sizedInsulated

Overall 100%Duofoil+ 85%

TC Braid


Originalfor 2kVApplications

3 14-2 Yes1 -

Full-sizedInsulated


TC Braid


OriginalSymmetricalfor 2kVApplications

3 1-4/0 Yes




(100%Coverage)

Yes Yes Yes Yes Yes Yes Yes Yes

Original with

Haloarrest

Low SmokeZero HalogenJacket

3 16-2 Yes 1 -Full-sizedInsulated


TC Braid

Yes Yes LSZH Yes Yes Yes Yes Yes Yes

OriginalSymmetricalwithHaloarrestLow SmokeHalogenJacket

3 1-4/0 Yes




(100%Coverage)

Yes LSZH Yes Yes Yes Yes Yes Yes

OriginalInterlockedArmor

3 16-2 Yes1 -

Full-sizedInsulated


TC Braid

Yes Yes YesMeets

MC Yes Yes Yes Yes Yes

OriginalSymmetricalInterlockedArmor

3 1-4/0 Yes


Into3 - Bare CU

Symmetrical


(100%

Coverage)

Yes Yes MeetsMC

Yes Yes Yes Yes Yes

BasicsSymmetrical 3 16-4/0 No

3 - Bare CUSymmetrical


(100%Coverage)

Yes Yes Yes Yes Yes

CU = Copper TC = Tinned Copper

Belden VFD Cable Matrix

Physicals Ratings

Cable TypeNo. ofCircuit

Conductors

ConductorAWG

TinnedCopper (TC)Conductor

No./Typeof

GroundsShielding

CircuitConductors

feature HeavyXLPE Insulation

Full-sizedDrainWire

PVCJacket

ERRating

1000VFlexibleMotorSupplyRating

600VUL 1277Type TC

2000VUL 1277Type TC

Under-ground(burial)

MSHAUL-

WTTC


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4

STEP 1

STEP 4 STEP 5 STEP 6

STEP 2 STEP 3

General Termination Instructions

To properly and e ectively terminate a VFDcable system, irst ensure the ollowing: Ideally, the shield and jacket should be

intact all the way back to the drive so theydo not introduce any jumping o points orthe common mode currents carried on thecommon mode current containment system.In this case, no special tools, materials ortermination kits are required.

Shield grounding cable glands should beavoided at the enclosure ingress as theymay introduce jumping o points or thecommon mode currents into the metal work in addition to undesirable and uncontrolledelectrical noise.

Intermediate termination o the cable ele-ments on terminal blocks should be avoidedas the terminations may signifcantly reduce

the ability o the shielding system to conductand contain harm ul high requency currents.

The cables outer jacket system serves animportant role in isolating the common modecurrent containment system. The outer jacketshould not be removed be ore the cableenters the drive proper as this introduces thepotential or uncontrolled ground currents.Care should be taken to minimize contactbetween exposed cable shield, and anyenclosure metal, especially in the closevicinity o sensitive equipment that is likely

present near the drive.

VFD Cable Termination Instructions Foil-Braid ConstructionsExternal and Self-Contained Drive Enclosures

A. Ingress the enclosure using an isolating cablegland with a suitable protection rating forthe enclosure and the environment. Allow asufficient length of cable to easily reach thedrive without unnecessary cable strain. Do notremove the outer cable jacket.

B. Secure the cable with suitable cable ties,or through cable duct as appropriate.

C. If the drive is open style, route the jacketedcable assembly back to the drive vicinity.

A. If the drive is in an internal enclosure, ingressthe drive through a suitable insulating cablegland. Measure and mark the cable to determinethe jacket strip location and cutoff length.

B. If possible, remove the measured cable andplace the end for preparation on a suitablework surface.

A. Remove the exposed shield andcable fillers where exposed.

A. Push the remaining braid forward,and use a tool to open the braid.

A. Neatly remove the outer cable jacket,exposing sufficient conductor to reach thedrive terminals, while still leaving some excessconductor length for trimming (after neatlyrouting to the drive terminals).

B. It is desirable to combine the shielding drainsand braid for termination intact at the groundterminal of the drive.

A. Push the exposed braid backover the cable jacket.

How to Terminate an External Enclosure (For Self-Contained Drive Enclosure Instructions - Nema 1,4,4x - skip to Step 2).


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5

STEP 13



A. Push the primary conductors and groundthrough an opening in the braid, separating the

intact braid system from the conductors.

A. Terminate the ground and drain permanufacturers recommendations.

A. Leave the drain wire inside the braid system. A. Apply heat shrink tubing to the drain and braid.

A. Apply 3-5 inches of heat shrink tubing over theentire cable assembly, centered at the jacketstrip point. Shrink this piece completely.

B. Secure the cable jacket to the drive (orenclosure) if it is not secured by a cable gland.

A. Route and trim the conductors to the powerterminals, leaving sufficient material for phasereversal, if necessary.

A. Terminate the motor leads per the drivemanufacturers recommendations.

B. Trim the ground wire to sufficient length toreach the drive ground terminal.


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6

STEP 1 STEP 2

A. Route and trim the conductors to the motorterminals, leaving sufficient material for phasereversal, if necessary. Use the terminationsystem recommended by the motormanufacturer.

B. Terminate the motor leads per the motormanufacturers recommendations, or trainedpractices of a qualified electrician.

C. Trim the ground wire to sufficient length toreach the motor ground terminal.

D. Heat shrink the drain wire covering and trim tolength for connection to the drive ground terminal.Strip to expose conductor as necessary.

E. Terminate the ground and drain usinga standard lug, or on the providedconnection point.

VFD Cable Termination Instructions Foil-Braid ConstructionsMotor Junction Box

A. Ingress the motor junction box through anisolating cable gland with a suitable protectionrating for the enclosure. Do not remove theouter cable jacket. Measure and mark the cablefor length. When possible, it is desirable toremove the cable from the motor junction boxfor ease of preparation.

B. Neatly remove the outer cable jacket, exposingsufficient conductor to reach the motor leadsand ground lug, while still leaving some excessconductor length for trimming (after neatlyrouting to the motor terminals).

C. Follow the cable preparation instruction aboveas specified for the drive end connection.

D. Secure the cable jacket to the motor bytightening the isolating cable gland.

How to Terminate at the Motor Junction Box


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7

STEP 1

STEP 4

STEP 2

STEP 5

STEP 3

STEP 6

VFD Cable Termination Instructions Foil-Braid Constructions Alternate Method: Conductive Cable Gland

A. Ingress the motor junction conduit box throughthe conductive cable gland.

A. Prepare the cable per the glandmanufacturers recommendations.

A. Trim the foil at least back to the prepared edgeof the braid.

B. Secure the cable to the gland per glandmanufacturers recommendations, and passthe cable into the motor junction box.

A. Terminate the ground and drain usinga standard lug, or on the providedconnection point.

A. Terminate the motor leads per the motormanufacturers recommendations, or trainedpractices of a qualified electrician.

A. Secure the cable jacket to the motor bytightening the cable gland lock nut.

B. Route and trim the conductors to the motorterminals, leaving sufficient material for phasereversal if necessary. Use the connectionsystem as recommended by the motormanufacturer.

C. Trim the ground wire to sufficient length toreach the motor ground terminal.

D. Heat shrink the drain wire(s) covering and trimto length for connection to the drive groundterminal. Strip to expose conductoras necessary.

How to Terminate in a Conductive Cable Gland

Note: It may be more desirable to terminatethe braid in a conductive cable gland at themotor connection. I so, suitable conductivecable glands are available through your BeldenDistributor. It should be noted, however, that

this will be no more e ective or common modecurrent containment than terminating thebraid intact, and will involve a more expensiveconnector. This connection may provideadditional mechanical security, depending on

the connector selection, and could reduceEMI in very close proximity to the motor

junction box.


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A. Trim back the copper tape shield, and any fillersin the cable.

B. De-cable the exposed conductors and grounds.

A. Combine the ground wires by twisting themtogether. Apply heat shrink tubing to thecombined grounds.

B. Secure the cable jacket to the motor bytightening the isolating cable gland.

C. Route and trim the conductors to the motor

terminals, leaving sufficient material for phasereversal, if necessary. Use the connectionsystem as recommended by the motormanufacturer.

D. Terminate the motor leads per the motormanufacturers recommendations, or trainedpractices of a qualified electrician.

E. Trim the ground wire to sufficient length toreach the motor ground terminal.

F. Terminate the ground using a standardlug, or on the provided connection point.

A. Ingress the motor junction box through anisolating cable gland with a suitable protectionrating for the enclosure. Do not remove theouter cable jacket.

B. Measure and mark the cable for jacket removalinside the motor junction box.

C. Neatly remove the outer cable jacket, exposingsufficient conductor to reach the motor leadsand ground lug, while still leaving some excessconductor length for trimming after neatlyrouting to the motor terminals.

How to Terminate at the Motor Junction Box

STEP 7 STEP 8

A. Trim the ground wire(s) to sufficient length toreach the drive ground terminal.

B. Terminate the ground per the drivemanufacturers recommendations. Note thatthere is no shield termination for copper tapeshielded constructions.

A. Route and trim the conductors to the powerterminals, leaving sufficient material for phasereversal, if necessary.

B. Terminate the motor leads per the drivemanufacturers recommendations. Use lugsand ferrules as appropriate. No special piecesare required.

VFD Cable Termination Instructions Copper Tape Shield ConstructionsMotor Junction Box


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Belden VFD Cable Termination FAQs

Commonly askedquestions aboutBelden VFD cables.

More Questions?Contact Belden

Technical Supportat 1.800.BELDEN.1 (1.800.235.3361).

Does Belden require a proprietaryconnector for VFD cables? Belden VFD Cables are 100% compatible with a wide variety of popular,commercially available connectors from most established suppliers.Because the connector needs of each application are specific to theapplication requirements and codes, your Belden distributor can helpselect the most appropriate connector options available.

Do I terminate the shield at both ends? Drive cable shields should always be terminated at the motor andat the drive. Intermediate termination of the ground or shield is notrecommended. The shield acts as a conductor for common mode currentcontainment. Failure to terminate the shields and grounds properly couldresult in harmful electrical noise or destructive common mode currentsflowing in the ground grid. Intermediate grounding of the shield can causethe unintended release of shield currents and resulting electrical noise.

My drives are pre-wired to terminalblocks should I connect there? While you can terminate at prewired terminal b locks, the use of unshieldedconductors from the terminal block to th e drive can create significantelectrical noise, which may affect other sensitive components, ornetworks within the enclosure. Connections on terminal blocks canalso reduce the effectiveness of the shielding and should be avoidedwhen possible.


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Additional Information

I you need in ormation on the type o VFDcable that is appropriate or your specifcinstallation, or i you have questions relatedto the instructions given within this guide,please contact Belden Technical Support at1.800.BELDEN.1 (1.800.235.3361).

Additional in ormation is also available onBeldens website at www.belden.com .Here, you can view VFD Cable Procurement

Documentation, or you can download Beldens VFD Cable Size Selection Guide (Based on MoHP), VFD Cable Product Bulletin #316, and aCapabilities Overview or 2000V VFD cables.

Can I use parallel runs for ease of installation? Parallel runs can be used for most VFD installations, and provide easierpulls and terminations for the installer. Care should be taken to ensurebalanced loading in the cables, and where multiple motor winding setsare present (for example in a 12 lead motor which has 4 sets of windings )individual cables should carry a dedicated motor winding set. I f thiscannot be determined, then common phases should be bussed togetherat the motor junction box. All T1 leads should be bussed together in themotor junction box, all T2 leads bussed together in the motor junctionbox, and all T3 leads bussed together in the motor junction box. Failureto balance the loads through bussing, or winding alignment will result inadditional cable shield currents and potential cable heating.

When cables are adequately space in a cable tray, no additionalde-rate should be required.

Will Belden VFD cables eliminatereflected wave voltages? No, but the lower capacitance conductors will effectively increasethe distance before the buil dup of reflected waves, in some cases thedifference in critical cable length can be as much as 3 times fart herwith Belden VFD Cables compared to THHN in Conduit. This can lead tosignificant differences on motor and cable insulation stresses, and may result in longer motor or cable life. The critical distance is different forevery drive, cable, and motor combination.

Can I run multiple motor cables in a conduitor cable tray without capacitive losses? Belden VFD Cabl es will eliminate the potentially s ignificant current lossesassociated with cable charging of nearby conductors.

Are Belden VFD Cables suitablefor applications with moderate flexing?Belden Original Foil Braid VFD Cables are tested to over 1 million flexeswith a bending radiu s of not more than 10 times the cable diameter.

VFD Cables overcome the challenges found inthe toughest of environments.


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VFD Cable Termination Guide