Damamged THHN

Status
Not open for further replies.
mdshunk said:
On page 13 of this Southwire PDF, they talk about repairing the nylon jacket of the new SimPull with electrical tape.

http://www.southwire.com/Southwire/StaticFiles/Text/RSTimeAndMotion.pdf
Click to expand...
Holy cow that thing was like 20 pages long.
I had the Southwire guy come out years ago because the nylon jacket wouldnt stay on the cable. It peeled off as we were pulling it in. What a pain.
He sent out new reels and asked us if we would mind "getting rid" of the origional wire. About 2000' of 600mcm..... We were able to help him out.
Southwire also paid us to pull out the old wire and repull the new wire.

Win Win??
 
jrannis said:
Southwire also paid us to pull out the old wire and repull the new wire.

Win Win??
Click to expand...

So the wire was already in and you removed it because the nylon jacket was coming off.

Something is wrong here, Dave Mercier of Southwire says,
The nylon actually is stripped away for the UL acceptance test. Therefore, if the nylon is scraped off, but the plastic underneath is intact, an appropriate response usually is "Good; it's done its job," and a green tag.
Click to expand...

The nylon jacket does not add to the insullation value or the dielectric strength per the UL acceptance test.

Roger
 
Outer sheathing

Outer sheathing

I wired a store in NC where the sheathing got ripped by a wood spur. She megged fine, so I threw tape around her. Did I like it? No, I did not. But after sticking the megger to it, I was confident.

Again, personal opinion!
 
roger said:
So the wire was already in and you removed it because the nylon jacket was coming off.

Something is wrong here, Dave Mercier of Southwire says,

The nylon jacket does not add to the insullation value or the dielectric strength per the UL acceptance test.

Roger
Click to expand...

The rest of the story is that we insisted that the wire be megged by a third party. The run was underground and to everyones suprise the wire actually failed. Must have been more to the problem than the nylon jacket.
 
jrannis said:
The rest of the story is that we insisted that the wire be megged by a third party. The run was underground and to everyones suprise the wire actually failed. Must have been more to the problem than the nylon jacket.
Click to expand...

The Nylon helps to protect the PVC during pulling. It the Nylon jacket was damaged it is possible the PVC insulation was also damaged during the pull.
 
I emailed a friend of mine with UL. Here is his reply:

Ryan: The answer is yes, that nylon jacket is simply for added protection during installation and not required as a part of the overalll insulation.
 
roger said:
So the wire was already in and you removed it because the nylon jacket was coming off.

Something is wrong here, Dave Mercier of Southwire says,

The nylon jacket does not add to the insullation value or the dielectric strength per the UL acceptance test.

Roger
Click to expand...

I just wonder; if it does not have any other function than to facilitate pull then why provide repair instructions AFTER the pull. Don't forget that there could be stripped nylon remains INSIDE the conduit. Apply bandaid to the cancer?!
 
jim dungar said:
The Nylon helps to protect the PVC during pulling. It the Nylon jacket was damaged it is possible the PVC insulation was also damaged during the pull.
Click to expand...

Even if the PVC insulation was not damaged, the alleged protection against chemical attack by gasoline, grease and whatnot is gone, so the wire INSIDE the conduit is now THHW and nothing more.
 
weressl said:
I just wonder; if it does not have any other function than to facilitate pull then why provide repair instructions AFTER the pull.
Click to expand...

Laszlo, where did you see repair instructions for this nylon jacket?

weressl said:
Don't forget that there could be stripped nylon remains INSIDE the conduit.
Click to expand...

Not to mention dirt, dust, spiders, etc..., none of which is much of a concern.

weressl said:
Apply bandaid to the cancer?!
Click to expand...

I don't understand, the insullation is not affected by taking the jacket off, so if the conductor is not installed in some high chemical enviroment there is no deterioration (cancer) to worry about.


Roger
 
roger said:
Laszlo, where did you see repair instructions for this nylon jacket?



Not to mention dirt, dust, spiders, etc..., none of which is much of a concern.



I don't understand, the insullation is not affected by taking the jacket off, so if the conductor is not installed in some high chemical enviroment there is no deterioration (cancer) to worry about.


Roger
Click to expand...

Somebody posted Southwire's instruction on another post on this thread.

The comment was made that the nylon is to facilitate pull AND provide chemical resistance. So chemical resistance is gone, therefore the material no longer fulfills its functions as installed, since the ease of pull function is irrelevant AFTER the installation.

My beef is why repair the nicks where it is visible, where you can't do anything about the areas where it is inacessible.
 
weressl said:
My beef is why repair the nicks where it is visible, where you can't do anything about the areas where it is inacessible.
Click to expand...

If gasoline and grease protection is not required there is no need to repair or replace the cable.

If this protection is required and jacket issues are noticed and are accessible before the pull it makes sense to have jacket repair instructions. If jacket issues are noticed after a pull then the conductors need to be replaced.

edit: grammar
 
Last edited:
weressl said:
My beef is why repair the nicks where it is visible, where you can't do anything about the areas where it is inacessible.
Click to expand...

I don't repair it and have never seen it done, if I was wiring say a Bridgeport machine where oil could be expected I would be much carefully.

I have actually intentionally stripped off the plastic where is has been torn up so that it looked better.
 
I'm an electrical engineer from the Netherlands so not well familiair with the USA / UL coding of cables but enthousiastic learning the NEC (export to you :))

I have (I guess )a simple question
The Nec uses several abbreviation for cable types such as THHN ; SJ etc
I know what they means but if I have a cable (hookup wire) from a European manufacturer that has
a PVC isolation,
a max temp of 90C ,
no nylon outer sheat,
approved by European NRTL or produced according to harmonized European standards, is it than correct to say it is actual THH and can it be used as such? or is it only THH if its marked as such
thx
 
Peter the Dutchie said:
I'm an electrical engineer from the Netherlands so not well familiair with the USA / UL coding of cables but enthousiastic learning the NEC (export to you :))

I have (I guess )a simple question
The Nec uses several abbreviation for cable types such as THHN ; SJ etc
I know what they means but if I have a cable (hookup wire) from a European manufacturer that has
a PVC isolation,
a max temp of 90C ,
no nylon outer sheat,
approved by European NRTL or produced according to harmonized European standards, is it than correct to say it is actual THH and can it be used as such? or is it only THH if its marked as such
thx
Click to expand...

Pieter,

I believe that no substitution can be made as you described it. The AHJ would have no means of verifying the equivalency.
 
ryan_618 said:
I emailed a friend of mine with UL. Here is his reply:

Ryan: The answer is yes, that nylon jacket is simply for added protection during installation and not required as a part of the overalll insulation.
Click to expand...

I would question that answer as the manufacturer claims: The nylon covering provides excellent mechanical strength and resistance to oil, gasoline and chemicals. Does UL test to verify the mechanical strength and chemical resistance? Mechanical strength is a vague term without further definition. Is that refer to abrasion, impact resistance, retaining the thermoplastic PVC form during and after the short circuit? The chemical resistance is obviously compromised and repairing it with +33 or like may NOT restore the same resistance. The AHJ can insist that if a cable was installed as THHN then it maintains all its qualities as such as it is not the AHJ responsibility to determine if chemical resistance is needed in that application, but only that the installation material is not compromised in its intended function.

That UL strips the nylon for dielectric strength test just simply does not make sense to me.
 
Laszlo, if you go back and read post #8 you will see that where the discussion of repairing a cable sheath comes into play, it is addressing NM cable, not the nylon jacket of THHN/THWN.

Roger
 
Status
Not open for further replies.
Top