VFD DLO cable

[rivecar44]

Thoughts of using DLO cable, load side of VFD. DLO cable is flexible, great to work inside vfd cabinet tight space and sharp turns, and 2kV rating. we will run ground cable inside the same conduit, and ground the conduit at both ends, either with a strap or bushing if RMC PVC coated.

 

[zbang]

The usual reminder- DLO is not an NEC article 400 cable type, however lots of it is dual-listed as RHW. A better question would be about using fine-strand cable on the load side, which could encompass RHW, SC, W, and even SO (check the voltage ratings).

 

[retirede]

You also need to check if your terminations are acceptable for use with fine strand wire.

 

[qcroanoke]

You also need to check if your terminations are acceptable for use with fine strand wire.

And from what I've heard it is not easy to pull.

 

[Birken Vogt]

I have occasionally seen Cobra wire which is also high-stranded but has a slick insulation on the outside. I believe it has regular NEC ratings as well.

 

[don_resqcapt19]

And from what I've heard it is not easy to pull.

I did a project with a couple of 1500 hp motors where we installed DLO/RHW in conduits for about 100'. Did not seem to pull harder than traditional conductors. You do have to be careful to get the wire pulling lube to completely cover the conductors as a "dry" spot will really drag.

 

[SceneryDriver]

I did a project with a couple of 1500 hp motors where we installed DLO/RHW in conduits for about 100'. Did not seem to pull harder than traditional conductors. You do have to be careful to get the wire pulling lube to completely cover the conductors as a "dry" spot will really drag.

I had to pull DLO / welding cable with neoprene insulation through conduit a several years ago, and someone suggested using baby powder instead of traditional lube. I was skeptical, but the conductors practically fell into the conduits - the talc was amazingly slick. No sticky mess when done, and the electrical room smelled nice too!


SceneryDriver

 

[garbo]

I had to pull DLO / welding cable with neoprene insulation through conduit a several years ago, and someone suggested using baby powder instead of traditional lube. I was skeptical, but the conductors practically fell into the conduits - the talc was amazingly slick. No sticky mess when done, and the electrical room smelled nice too

 

[garbo]

I would check with the AHJ before using any talc powder. First its not an approved pulling lube and second if wire ever shorted out the powder might cause an explosion. I worked at a large candy plant years ago where they had three large starch machines that made impressions in think it was corn starch then poured jelly, marshmallow etc into trays. Room had dust collectors but dust was still airborne. Had to wait a hour then hose area down after production stopped before welding. Entire room used explosion proof fittings, boxes limit switches etc.

 

[synchro]

I would check with the AHJ before using any talc powder. First its not an approved pulling lube and second if wire ever shorted out the powder might cause an explosion.

Talc powder is not combustible and will not explode. It can contain small percentages of asbestos and crystalline silica, though.
But if the powder contains cornstarch then that can explode.

 

[don_resqcapt19]

I would check with the AHJ before using any talc powder. First its not an approved pulling lube and second if wire ever shorted out the powder might cause an explosion. I worked at a large candy plant years ago where they had three large starch machines that made impressions in think it was corn starch then poured jelly, marshmallow etc into trays. Room had dust collectors but dust was still airborne. Had to wait a hour then hose area down after production stopped before welding. Entire room used explosion proof fittings, boxes limit switches etc.

Of course everything used has to be "approved" but talc is the specified pulling lubricant for some hospital isolated power systems as traditional lubricants can increase the capacitance of the conductors and reduce the isolation.
As far as the explosion issue, that only happens with combustible dusts, talc is not a combustible dust.

 

[Birken Vogt]

Baby powder is part cornstarch, don't know how much. So it is potentially combustible. I guess you need to use the proper talc.

 

[Jraef]

Talc powder is not combustible and will not explode. It can contain small percentages of asbestos and crystalline silica, though.
But if the powder contains cornstarch then that can explode.

+1 on this. We built a control system for a machine that packed the explosive igniters for air bags. In the extensive testing prior to going live with the explosive powder, we used talc as an analog because it specifically was NOT explosive.

 

[Jraef]

You also need to check if your terminations are acceptable for use with fine strand wire.

This is usually the biggest issue. I have never seen a standard mechanical lug on a VFD that is rated for higher than Class B or maybe C stranding (ie typical building wire).

What you usually have to do is remove the factory lugs and using the special crimp lugs for high strand count (usually Class D or higher) cable. So before starting, double check with the VFD supplier if it’s OK to remove their lugs without violating the UL listing of the drive.

 

[qcroanoke]

What you usually have to do is remove the factory lugs and using the special crimp lugs for high strand count (usually Class D or higher) cable. So before starting, double check with the VFD supplier if it’s OK to remove their lugs without violating the UL listing of the drive.

If that's the case you should check with mfgr. to see if they allow DLO/RHW to even connect to their drive.

 

[don_resqcapt19]

This is usually the biggest issue. I have never seen a standard mechanical lug on a VFD that is rated for higher than Class B or maybe C stranding (ie typical building wire).

What you usually have to do is remove the factory lugs and using the special crimp lugs for high strand count (usually Class D or higher) cable. So before starting, double check with the VFD supplier if it’s OK to remove their lugs without violating the UL listing of the drive.

If they don't want you to replace the lugs, you maybe be able to use these pin adapters. (see page 2)
However if the VFD is in its own enclosure, it is not likely there would be physical room to install a pin adapter.

 

[SceneryDriver]

If they don't want you to replace the lugs, you maybe be able to use these pin adapters. (see page 2)
However if the VFD is in its own enclosure, it is not likely there would be physical room to install a pin adapter.

A crimped bootlace ferrule solves the high strand count issue, without growing the length of the termination.


SceneryDriver