VFD cable splicing

[weressl]

well, it's 600volt cable, so if you can get the same cable, it should be fairly
straightforward.... hipress butt splices for the power leads, stagger them so
they are not all at the same point, cold shrink with 3m cold shrink, do the same
with the grounds, and then wrap half lap the whole thing with copper shielding
foil, making sure the shield is maintained. i'm assuming the existing shield is a
copper foil product, not metallized mylar or something like that. after i got it
all wrapped, get someone who knows how to solder well to solder the patch
foil to the existing foil, without harming the material underneath.

then cover the whole thing with 3m cold shrink. i'm partial to 3m cold shrink
'cause it's a proven product, used in MV cable splicing kits. it's thick, it's
moisture tight, it pulls down tight, and seals.

megger and check everything for continuity with a good ohmmeter. smile,
and light it up.

how much cable is involved here? if this is a short run, it may not be worth it,
but if it's running over the river and thru the woods in a cable tray, it'd be
worth doing it.

pick someone you've got with good hand skills to do it... if anyone near you
is a cable splicer, that'll do nicely.

Actually it is more likely a 2000V insulation. That's why I suggested to double up - at least - on the heat shrink. I would stay away from soldering though....see my suggestion in the other post.:smile:

 

[Fulthrotl]

You have NO IDEA what it took to tone it down.......

try not to hurt yourself or anything..... :smile:

 

[Fulthrotl]

Actually it is more likely a 2000V insulation. That's why I suggested to double up - at least - on the heat shrink. I would stay away from soldering though....see my suggestion in the other post.:smile:

yeah, a 2000 volt jacket.... i got that, but the motor and vfd are <600 volts,
correct?

however, your point is well taken.... nobody has ever said.... "damn. with that
insulation, it'll never short out......":smile: i was just looking at the working
voltage.....

 

[weressl]

yeah, a 2000 volt jacket.... i got that, but the motor and vfd are <600 volts,
correct?

however, your point is well taken.... nobody has ever said.... "damn. with that
insulation, it'll never short out......":smile: i was just looking at the working
voltage.....

Nope, the individual conductor insulation would be 2000V and even though the ASD rated motor will still say 460V to be the operating voltage the actual insulation is higher then other 460V non-ASD rated motors and have other diostinctive featrues as well.

 

[Fulthrotl]

Nope, the individual conductor insulation would be 2000V and even though the ASD rated motor will still say 460V to be the operating voltage the actual insulation is higher then other 460V non-ASD rated motors and have other diostinctive featrues as well.

ok, butch... i stand corrected.... use more dynamite....

 

[Besoeker]

FWIW....
We (the company we) have never used "special" VSD cable. We normally use standard steel wire armoured cable. If we need to extend a cable or make a joint, it is in a terminal box, typically a wall-mounted stainless steel IP66 box. Conductor terminations (lugs) are usually of the copper compression type. For some applications, an intermediate terminal box is unavoidable. Submersible pumps are an example in my field.

Spliced joints, taped, sleeved, or otherwise are generally not permissible on the basis that it must be possible to physically inspect and test all joints and terminations and I can see the merit in that.

Maybe it's on the basis of that background that I'd prefer to avoid splicing for this application.

 

[petersonra]

If I had to guess, I might well guess that the vast majority of VFDs are installed using regular old wire as opposed to expensive and hard to run VFD cable.

I have my doubts about whether VFD cable is really worth the extra cost, especially if you are running in metal conduit.

 

[drbond24]

If I had to guess, I might well guess that the vast majority of VFDs are installed using regular old wire as opposed to expensive and hard to run VFD cable.

I have my doubts about whether VFD cable is really worth the extra cost, especially if you are running in metal conduit.

I agree with your guess, but not your doubts.

http://www.ab.com/drives/techpapers/ieee/ieee.html

Go there and read everything that has Gary Skibinski's name on it.

 

[Smart $]

... I would stay away from soldering though....see my suggestion in the other post.:smile:

It's not really a bad idea to solder the foil, but I suggest doing it in a manner which WILL NOT affect the conductors insulation. By that I mean...
pull in the new cable so that the foil wrap where the splice is to occur is opposite that of the existing section. This is so you can unwrap the cable's foil a couple times or so and get the solder point away from any insulation. The rest can be gleaned from the depiction below. The down side is when either end's foil is underwrapped it's a bit more difficult to work.

An alternate method is to just bridge the solder points, wrap back into the group, then half-lap wrap again with new foil.

 

[weressl]

FWIW....
We (the company we) have never used "special" VSD cable. We normally use standard steel wire armoured cable. If we need to extend a cable or make a joint, it is in a terminal box, typically a wall-mounted stainless steel IP66 box. Conductor terminations (lugs) are usually of the copper compression type. For some applications, an intermediate terminal box is unavoidable. Submersible pumps are an example in my field.

Spliced joints, taped, sleeved, or otherwise are generally not permissible on the basis that it must be possible to physically inspect and test all joints and terminations and I can see the merit in that.

Maybe it's on the basis of that background that I'd prefer to avoid splicing for this application.

..and are you remaining compliant with the IEC EMI/RFI directives?
Steel wire armor is not an effective way of stopping eitehr RFI or EMI, EMI actually can heat up the steel. Beryllium copper is the top performer and choice of high intergrity shielding. Unfortunately ir is difficult to produce in a wire form but it can be used for enclosure lining. Tightly woven nickel plated copper mesh offers the highest % cable protection.

http://www.amercable.com/doc/catalogs/industrial/37-102VFD.pdf

 

[Besoeker]

..and are you remaining compliant with the IEC EMI/RFI directives?

Yes, with the applicable IEC directives.
The requirements are different depending on, for example, application and environment.
For what we do, much of IEC 60947 applies, IEC 61000-6-2, IEC 61800-3, 2nd environment and numerous others. And the ever pervasive BS EN 7671.

 

[Ranch]

Correct me if I'm wrong. Does anyone know what the installed distance VFD to motor is and what the proposed extended distance will be? Sorry if I missed it

Splice away, but remember, THHN is a poor choice on PWM power (XL types are only a dime more)

 

[wireman]

If the VFD manufacturer says to pull new cable then you should tell your customer that is the manuf.'s recommendation.

If you don't pull new and splice it and then there are operational issues with the VFD the VFD manuf. will use that as an excuse for why the drive is not working properly.

If the customer tells you to splice it then inform them (in writing) that you can't be responsible for the drive's operation because the install doesn't meet manuf's requirements.

 

[weressl]

If the VFD manufacturer says to pull new cable then you should tell your customer that is the manuf.'s recommendation.

If you don't pull new and splice it and then there are operational issues with the VFD the VFD manuf. will use that as an excuse for why the drive is not working properly.

If the customer tells you to splice it then inform them (in writing) that you can't be responsible for the drive's operation because the install doesn't meet manuf's requirements.

The ASD manufacturer should have NO say about whether the cable can be spliced or not. They do NOT manufacture the cable nor do they specify WHOSE cable will perform satisfactorily with their drives and which ones won't. There is NO manufacturing standard for ASD shielded cable so each manufacturer?s will be different with different physical parameters. If you wish to be absolutely certain about it, you may ask the cable manufacturer to advise the method of splicing.