Conductor insulation damage

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kwired

kwired

Electron manager
Location
NE Nebraska
electrofelon said:
Ok, sounds reasonable. I personally can't imagine using a knife to skin romex. I am used to a super sharp razor and going at it with something dull, whether it be a razor or a knife, is the best may to cut the inners.
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Takes a little skill to know how to sharpen a knife.

This knife is what I have used nearly all my career, When getting a new one I usually grind that hook on the end down and end up with a straighter, but still a slight hook to it, blade. I use that for NM, UF, other NM jackets cords/cables, stripping larger conductors, cutting open boxes, etc.
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Have used "razor knives" when this wasn't readily available for whatever reason, and do alright with those as well, but just gotten used to the feel of not only the blade but the handle as well and because of that I am most comfortable with it for the most part.
 
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Teaser2

Member
Location
MDDENJ
Occupation
Electrician/EE
I have watched so many TikTok videos of some of the electricians; electricians wanna be... who are too comfortable with using their knives, wire strippers etc. while they are showing off their knife skills and speed :) In addition, how carelessly they pull their NM-"romex" cables. I get nervous by watching them, also saying, you got baxxs...It is matter of not when, how many wires you will compromise by damaging the insulation and the wire.
 
electrofelon

electrofelon

Senior Member
Location
Cherry Valley NY, Seattle, WA
Teaser2 said:
I have watched so many TikTok videos of some of the electricians; electricians wanna be... who are too comfortable with using their knives, wire strippers etc. while they are showing off their knife skills and speed :) In addition, how carelessly they pull their NM-"romex" cables. I get nervous by watching them, also saying, you got baxxs...It is matter of not when, how many wires you will compromise by damaging the insulation and the wire.
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If one can't score a cable sheath properly and consistently with a razor, they need to reevaluate their career choice.
 
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macmikeman

Senior Member
Location
Planet macmikeman
I was informed recently that ScotchCoat is no longer manufactured? Due to some sort of environmental concerns. ScotchCoat was very helpful in situations like the one in the op's pictures.
 
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macmikeman

Senior Member
Location
Planet macmikeman
Also, we are required in dwellings to install AFCI protection on most all new branch circuits running at 120 volts, and we all know they work so terribly well in just such a situation where the is a tiny nick in the insulation, that we are all thrilled to cough up the extra 50 bucks . I know this because electrical inspectors told me so.
 
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jap

Senior Member
Occupation
Electrician
macmikeman said:
Also, we are required in dwellings to install AFCI protection on most all new branch circuits running at 120 volts, and we all know they work so terribly well in just such a situation where the is a tiny nick in the insulation, that we are all thrilled to cough up the extra 50 bucks . I know this because electrical inspectors told me so.
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I guess I don't.

How does an AFCI aid in any way with a nick in the insulation?

JAP>
 
4-20mA

4-20mA

an analog man in a digital world
Location
Charleston SC
Occupation
Instrumentation & Electrical
jmellc said:
That would be good, like some tray cable has. But it can cut your fingers too. 🤣
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For sure, and no one mentioned any 48 pair shielded tray cables... even with the rip cord... after you peel back shield wraps for a week and land 1.3 million wires on a terminal strip, your fingertips hate you too.
 
J

jap

Senior Member
Occupation
Electrician
ptonsparky said:
Just a nick? Nope, NWIH, neither will a GFCI and I am a firm believer in them.
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I was replying to a comment where I assumed someone thought "we all knew" an AFCI didn't work well with a conductor that had a nick in it.

Some do think that by the way.

I'm not part of that group.

An AFCI not working well has nothing to do with a nick in a conductor, yet, you seem to agree with that, and,refer to me as sarcastic.

If you felt that way You probably should have quoted that line and referred to it as "note of sarcasm".

JAP>
 
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winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Just to clarify for everyone involved: Sarcasm often doesn't come through clearly in text discussions that span different regions of the country or the world. You don't hear tone of voice, you don't see nuances of body language. You can't see the raised eyebrows and the half smile.

I am pretty certain that @macmikeman was being sarcastic with:
and we all know they work so terribly well in just such a situation where the is a tiny nick in the insulation, that we are all thrilled to cough up the extra 50 bucks . I know this because electrical inspectors told me so.
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I am pretty certain that @ptonsparky was pointing this out.

I am pretty certain that @jap is not being sarcastic at all, and is expressing that AFCIs won't help with nicked insulation, which I think means that AFCIs won't do their claimed job.

But since reading sarcasm requires reading between the lines, I'm not absolutely certain of the above.

It seems to me that if you have nicked insulation, in a stable system where the exposed conductor never touches anything else, that you don't have a fault and have nothing to detect. The _risk_ from nicked insulation is a small high resistance arcing fault occurring which causes heating and fire. The (faint) hope is that AFCIs will do a better job of detecting these sort of low level heat producing faults, and protect the wiring from faults caused by things like nicks, loose connections, etc.

Most people on this board (myself included) are less than sanguine about the true ability of AFCI devices to make a sufficient difference to be worth their cost.

-Jon
 
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