I need some documented material as how to properly remove the jacket from SE, SO, SJ, ect. Also the proper way to remove the insulation from THHN, THWN, ect. I was taught in school to use a knife and whittle the insulation off not damaging the conductor. A fellow worker accidently cut himself and the company now wants to make sure this is the safe and correct way. I do not need opinions but facts and documents to prove my case or the correct approved method.
Cable / Wire Stripping
- Thread starter jamesoftn
- Start date
- Status
barbeer
Senior Member
- Location
- Pinellas County, FL
Ask an electrical trade teacher for references? Book on the internet? Anything in OSHA or NESC?
Rick Christopherson
Senior Member
I am not a fan of the whittling method of removing jacket from these cable types for the very reason you bring the question up, plus the risk to the internal conductor insulation.
For these types of cables, I prefer to take advantage of the stretch/tension of the jacket. I will bend the stranded cable sharply, and then press (not slice) the edge of the knife into the jacket at the crown of the sharp bend until the tension on the jacket causes it to pull apart. This causes the jacket to split and separate long before the knife edge actually penetrates the jacket, thereby eliminating the possibility of nicking the insulation on the inner conductors.
It makes no difference what the cable type, insulation type, conductor type, I will NEVER, EVER whittle an insulation away from cables or conductors, because you will have less control over penetration--especially on removing the final insulation on a metallic conductor.
Oh, I guess a better explanation of this is to understand that the copper will not stretch, but the insulation MUST stretch when you bend the wire due to a larger radius of the bend. The same is true regarding a multi-wire cable with insulated conductors covered by a jacket. The length of the material is dependent on the bend radius, so the outer materials are stretched farther and therefore easier to split.
For these types of cables, I prefer to take advantage of the stretch/tension of the jacket. I will bend the stranded cable sharply, and then press (not slice) the edge of the knife into the jacket at the crown of the sharp bend until the tension on the jacket causes it to pull apart. This causes the jacket to split and separate long before the knife edge actually penetrates the jacket, thereby eliminating the possibility of nicking the insulation on the inner conductors.
It makes no difference what the cable type, insulation type, conductor type, I will NEVER, EVER whittle an insulation away from cables or conductors, because you will have less control over penetration--especially on removing the final insulation on a metallic conductor.
Oh, I guess a better explanation of this is to understand that the copper will not stretch, but the insulation MUST stretch when you bend the wire due to a larger radius of the bend. The same is true regarding a multi-wire cable with insulated conductors covered by a jacket. The length of the material is dependent on the bend radius, so the outer materials are stretched farther and therefore easier to split.
Last edited:
Twoskinsoneman
Senior Member
- Location
- West Virginia, USA NEC: 2020
- Occupation
- Facility Senior Electrician
I've always used an electricians knife and scored it down the side but recently (last 3 months) I have learn the benifits of a cable slitter. The job I'm on now (industrial) has me skinning hundreds of cables.
I use this now
I took me a couple of cables to get used to it but now I am 2-3 times faster with it than a knife. Also since the blade swivels 90 degrees I can make a perfectly round slit first then turn the blade and make the slit down the side of the cable.
Once you learn to use it well it works awesome. Highly recommend.
It is a Paladin 1822
I use this now
I took me a couple of cables to get used to it but now I am 2-3 times faster with it than a knife. Also since the blade swivels 90 degrees I can make a perfectly round slit first then turn the blade and make the slit down the side of the cable.
Once you learn to use it well it works awesome. Highly recommend.
It is a Paladin 1822
I doubt that you will find any "facts".
You may find documentation but they will all be based on opinions.
The fact is, when you work with knives, you will eventually draw blood. Sometimes because the knife is too sharp but usually because it's too dull.
There is something called experience that teaches us how much force to use when ripping sheath of stripping big wire.
On sheath, I simply run the knife lengthwise, open it up and cut it off with dikes.
With big copper thhn, I whittle one time then ring it with my knife. The only awhward part is the back side. Sometimes I will whittle the front and back, then ring it. AL's a whole different story because you have more chance of damaging it when you whittle it all the way around.
electricalperson
Senior Member
- Location
- massachusetts
use a hawkbill knife. klein sells them and calls them sheepsfoot. they work great. i cut myself less with those than i do with a razor knife. just keep it sharp and it will work good
texassparky
Member
- Location
- Dallas / Ft. Worth
Our company had the same type of issues, mostly with razor knives, that most guys were pushing or pulling too hard so when it slipped, they were causing very severe cuts due to the razors sharpness...so the solution was pocket knives only...we cancelled that after doubling the injuries because guys dont keep their knives sharp...It is also easier to repair a nice clean cut from a razor than it is a big rip from a dull pocket knife...
- Status