I use a Specilized Products #NT2267 cable slitter
http://www.specialized.net/ecommerce/shop/layout.asp?product_id=210X800 to slit cable jackets. Used one even today on some 8/5 SO
wire. Once you get used to the technique of hooking the
jacket than rocking the blade back to ride the cut on the
jacket while not cutting into the
insulation below, it works well - to the
point that you can remove a layer of
insulation or
heat shrink at a time without slitting the cable below. Only costs about $21.00 each and it looks kind of like a
juice harp.
Otherwise, if not slitting the
jacket, to make a cut into it so I can remove the
jacket as a whole and not slitted such as for a
plug on a cable, I use professional Klien Journeymen 2000 series Dikes #J248-8 with the beveled head and case hardened tips that sell for about $25.00 each. When and if they get dull, it's full warranty.
http://www.kleintools.com/index.html With such a tool I grab the
wire, Pull and rock it off to the side than cut down on it to ensure that the
wire I cut within that pinch is nowhere near the insultaion of the conductors below. Five such pinch, pull, cuts, and most jackets on a
wire will pull right off. Otherwise, where needed, just the carefully placed pressure of the always sharp blade is sufficient to cut the remaining
jacket when the
wire is flexed to expose it.
It's a practice thing but one that ensures that no matter how great you are with the knife, you don't apply just a wee touch too much pressure with a knife blade directly onto the cable
jacket and
insulation of the conductors beneath. "I never cut too deep and by far am too much of an expert to fold my
wire at the cut to ensure I did not cut into the
insulation." Let's
face it we all once in a while make a mistake, using the dike method for cutting a cable
jacket is just much easier to do without thinking about it, and much less likely to cut into the
insulation.
Once that cable is stretched with use, all it takes is the slight cutting into the
jacket and you have conductors exposed - and that's why I am adimate about not using knives. Get a good pair of dikes, try the technique and see if amazingly enough it does not seem the most safe method not only for students but for all to use. No on type SC cable, I'm using medium cable cutters and slitting the
jacket down to the
wire, but on multi-conductor cable it works uniformly and safely.
Should I have to cut and slit some #6
THHN building
wire, than sure, it's that
utility knife, I'm not about to waste the blade on my medium cable cutter on such
wire, much less I'll probably have to slit the
jacket anyway to get it off and with that type of
insulation, the
utility knife blade works best. If I need to make some more solid 14GA wires for CamLoc
connector strain reliefs, and it is not just pulling off, I'll even consider using the
utility knife to remove the
jacket. These execeptions are that with building
wire, the conductors are much larger and have less strands to them than a
cord's wires that are easily cut.
As for utility knives, I use them and specify them to be used for cable looms. But only with one specific blade that mimics the above one. This is a topical debate that I was just discussing today in the idea that perhaps I would supply crew chiefs with shows blades of the type so they could thus supply the union toadies and everyone else damaging my cable, with a good knife blade. Just takes one misplaced cut on the
jacket of a cable with a normal
utility knife blade and that cable is damaged. We have hundreds of thousands of dollars in cable with cuts in it that is not coming from the shop, it's coming form the
road. All because it was too close to lunch or some
stage hand was distracted while cutting apart cable looms. My starting such a trend could change the industry considering the
level of tech I am working at. Give it a few years should such a option be adapted by us.
A hook blade is the solution. (And everyone wonders why I would want a copy of McMaster Carr at home. Part number 4927a18) Stanley part number 11-961 is a normal sized
utility knife blade that will fit into all utility knives, but as opposed to slitting with the downward pressure, slits with the upward pressure. Now consider this idea, you hook the tape from underneath and cut by sliding the blade along the tape with a slight downward if not upward pulling pressure. That as opposed to a downward pulling pressure that if even slightly too deep will cut into a cable
jacket if not inner conductors.
In the shop, I mandated the use of such blades and repairs on cable has gone way down. The only problems now are in old repairs before the
current method, or in field repaired cable that's usually electrical tape forming a temporary fix that will
peel off, or better yet, marked in yellow so such a cut can be properly repaired. It is extremely rare that a tech person in the shop while using the proper cable slitting much less tape cutting blade will slit the cable. There is no cutting
edge along the surface exposed to the cable
jacket so there is nothing to be damaging the
jacket. Such blades also work faster and easier.
Again, try these new tools before you form your ending opinion on skill being all that's needed to use a
utility knife. In addition to that cable slitter, today I used a actual electrician's knife today. I was slitting the cable on some 8/4
flat cable and needed to penetrate the outer
jacket in getting at the inner conductors. I only pull out the real knife when it's necessary to do such things. I even have a NMN cable stripper that's only used for that purpose. Takes longer with any such tool as it does with a basterdized but everyone uses knife to be as careful as necessary to slit cable jackets. Five grab/pull/cut's and it's done. Under 6 seconds and the cable is stripped. I don't have to worry about some complex cable
jacket slitter doing a proper job, it's just done. If using cable that does not pull, the dikes are much easier to control the depth of cut which varies with a knife due to it's sharpness. Indent a slit into the
jacket and fold the cable, you now have a cut that is vary rare to be too deep. Simple as that.
