Drive cable · Georgia
We buy VFD cable for variable-frequency drive installations
Symmetrical three-conductor cable with three bare grounds and a overall shield, built for the output of a variable-frequency drive. Reviewed on conductor size, shield type and footage.
- 16 AWG to 500 kcmil
- Three split grounds
- Foil or braid shield
01Overview
Why drive cable is built this way
A variable-frequency drive switches its output at high frequency, and the cable carrying that output has to do two jobs beyond conducting current. It has to hold the electrical field inside the assembly, which is what the shield does, and it has to provide a low-impedance return path for the common-mode current the switching produces.
That second job is why the grounds are split into three bare conductors laid symmetrically between the power conductors rather than bunched as one. The symmetry keeps the field balanced and the split grounds reduce the impedance of the return path. A coil of ordinary three-conductor tray cable will physically fit the same terminals and will not do the same thing.
02Specification
What a drive cable coil declares
- Construction
- Three symmetrical power conductors with three split bare grounds
- Sizes
- 16 AWG through 500 kcmil; 8 AWG and 2 AWG common on plant drives
- Voltage
- 600 V and 1,000 V; 2 kV on some medium-duty constructions
- Insulation
- XLPE, with a semi-conducting layer on the larger sizes
- Shield
- Overall foil with drain, braid, or foil and braid combined
- Jacket
- PVC or CPE, oil and sunlight resistant on tray-rated types
- Coils
- 250, 500 and 1,000 ft coils; heavier reels above 4/0
- Marking
- Type, size, voltage and shield description on the jacket print
The shield description on the print matters. A foil-only construction and a foil-plus-braid construction are different products at the same conductor size, and the braid is what carries the higher-frequency current.
03Drive cable we review
Drive cable we review
Foil-shielded drive cable
An aluminum foil shield with a drain wire over the symmetrical core. The common construction for smaller drives and shorter motor runs, and the one most often left over from a machine build.
Foil and braid shielded
A braid over the foil for lower shield impedance and better mechanical strength. Used on larger drives and on long motor leads. Reviewed on braid condition, since a braid that has been cut back hard at the end is difficult to terminate properly.
1 kV and 2 kV drive cable
Heavier insulation for drives running on higher DC bus voltages and for long leads where reflected wave voltage stresses the cable. The voltage class is printed and is the first fact to establish on an industrial coil.
Cut lengths from machine builds
Remainders after a panel or a machine was wired. Typically short and well documented, and best reviewed as a group by size, because a plant will hold twenty of them in the same cabinet.
04Evaluation
How a drive cable lot is reviewed
Size and voltage class first, then shield construction, then footage. Conductor size sets what the cable can feed and the voltage class sets which drives it can serve, and neither is reliably visible from the outside of a coil. The print settles both, and a coil without a readable print is measured instead.
Shield integrity is the deduction that matters most and the one sellers overlook. The shield is the reason the cable was bought; a coil with the braid crushed where something heavy was stacked on it, or with the foil torn back a foot from the end, has lost part of its purpose. Open one end, photograph the layup and the shield, and the review moves quickly.
Length and packaging finish it. Drive cable is stiff and holds a coil memory, so a loose coil that has lost its ties is harder to pull than a banded one. Give the coil count, the length from the tag and whether the coils are still wrapped, and say if any of them came off a drive that was relocated rather than a new build.
A drive output remains dangerous after the motor stops, because the DC bus holds a charge and the cable can retain voltage. Drive cable is only disconnected after the drive has been isolated and its bus proved discharged, by the plant’s own electricians.
05Seller terms
Before you sell: how it works
Four things a seller should be able to pin down before a truck is booked.
Verification
Footage is checked against the reel tag, the sequential marks on the jacket, the wrap count against the barrel, or a published weight per 1,000 ft — whichever the reel actually supports.
Payment
Payment method and timing are agreed in writing for the specific lot before anything is loaded or moved. No verbal number is treated as an agreement.
Paperwork
A bill of sale for the lot, and for utility material the owning utility’s release reference. Neither is optional and neither is created after the fact.
Freight
Collection is arranged as part of the terms. Say what can lift the reels and whether a 53-foot trailer can reach them, and the pickup is planned around that.
Sending a reel list and photographs costs nothing. A review is not a purchase, and nothing is bought, moved or scheduled until written lot terms are agreed for that material. Request a pickup when the lot is ready.
07Questions
VFD cable questions
Can ordinary tray cable be used on a drive?
It will carry current but not the shield and return path a drive needs. VFD cable is built with symmetrical conductors and split grounds for that reason, and the two are not substitutes.
What do the three grounds do?
They provide a low-impedance return path for common-mode current, spread symmetrically around the power conductors. The arrangement is what distinguishes drive cable from three-conductor power cable.
Do you buy drive cable with the braid cut back?
Yes. A braid cut back at one end is normal on a part coil and is trimmed again at termination. Braid crushed or torn along the length is a deduction.
Is 1 kV drive cable accepted?
Yes, and it is the common class on plant drives. Voltage class, conductor size and shield type are reviewed together, since no one of them identifies the cable alone.
Open one end and photograph the layup
Size, voltage class, shield type and the footage on each coil. A photograph of the cut end shows the symmetry and the grounds in a single frame.