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The clear coat on THHN seems to get nicked up when I have to move it around a bit in boxes and esp. during pulls. Is this an issue? I keep quiet (as in don't point it out to the boss) but I wonder if this should be treated the same as repairing exposed copper etc? Again this is the clear coat I am talking about, not the colored insulation below it.

Thanks.
 

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Homer to Jebus
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IIRC, it is just an insulation protector and also helps with pulling. At least that's what I've been told by the Cerrowire plant manager. :whistling2:
 

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The clear coat on THHN seems to get nicked up when I have to move it around a bit in boxes and esp. during pulls. Is this an issue? I keep quiet (as in don't point it out to the boss) but I wonder if this should be treated the same as repairing exposed copper etc? Again this is the clear coat I am talking about, not the colored insulation below it.

Thanks.
There is no clear consensus on this unfortunately. Most people (me included) were taught that the nylon jacket on THHN was there for the purpose of helping to protect the PVC insulation from abrasion when pulling, but was not necessary for the insulation value. This concept is backed up by the fact that UL does the insulation testing of THHN with the jacket removed.

But others say that the jacket ADDS to the chemical resistance of the insulation, specifically to oils, solvents and chlorine based compounds that exist in a lot of industrial environments which can attack PVC, so any damage to it can compromise the insulation life.

Know your application and pick your team...
 
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Donuts > Fried Eggs
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My understanding is the nylon is what makes THHN gasoline resistant.

EDIT: I just took a look at UL 83 which covers the standards for testing conductor insulation types. The confusion is that for water-resistance testing of the insulation (5.5 and 5.7), the nylon covering is removed so that the underlying insulation is totally exposed.

But when testing oil and gas resistance of the conductor (5.14 and 5.15) the nylon covering must be left on during the time the conductor is immersed.

So it does sound like it's part of the petroleum resistance of the insulation design.
 

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My understanding is the nylon is what makes THHN gasoline resistant.

EDIT: I just took a look at UL 83 which covers the standards for testing conductor insulation types. The confusion is that for water-resistance testing of the insulation (5.5 and 5.7), the nylon covering is removed so that the underlying insulation is totally exposed.

But when testing oil and gas resistance of the conductor (5.14 and 5.15) the nylon covering must be left on during the time the conductor is immersed.

So it does sound like it's part of the petroleum resistance of the insulation design.
That's the way I've always understood it.
 

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Armed and Unhinged
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But when testing oil and gas resistance of the conductor (5.14 and 5.15) the nylon covering must be left on during the time the conductor is immersed.

So it does sound like it's part of the petroleum resistance of the insulation design.
That is what I was told from a very credible contractor in my area. Thank you for verifying.
 

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I was always taught that the nylon jacket was there to facilitate ease in installation. The fact that it is used as part of its test for oil resistance, I would assume that this would be important for some. I can not think of too many applications where this would be an issue, but I am sure they are there.
 

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I was always taught that the nylon jacket was there to facilitate ease in installation. The fact that it is used as part of its test for oil resistance, I would assume that this would be important for some. I can not think of too many applications where this would be an issue, but I am sure they are there.
We had some old machine tools that had the wires exposed inside of the machine and would be oil soaked, so we had to pay attention for nicks, that's how I was taught, it was for oil & gas resistance.
 

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Donuts > Fried Eggs
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It is funny that the nylon would be important, because god knows it does get destroyed pretty regularly.

I know I've seen what happens to some types of cable tray when exposed to lubricating oil and it turned that insulation into absolute silly-putty.
 

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I know I've seen what happens to some types of cable tray when exposed to lubricating oil and it turned that insulation into absolute silly-putty.
Machine tool coolant does the same thing. It pretty much dissolves any type of plastic in due time.
 
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