I am redoing some wiring in our house that involves breaking and
remaking some original connections -- ripping out and replacing boxes by
larger (e.g., two-gang by three-gang). I find that in some cases all the
conductors of the same color have been connected using crimps that have
then been taped over -- even the hots. Is this kosher? Surely wirenuts
provide better insulation than the tape. There could be 220/240 volts
between conductors in some boxes because there are Edison circuits involved.
Should I use wirenuts for the reconnections? Crimps and tape take up
And, while I think of it, is it OK to have circuits fed from different
breakers in the same box (e.g., outlet and light switch)? One could
assume that since the one circuit is dead (switched off at the panel),
the other is too.
Addressing the connection method: When I think of crimps, I think of the
type that already have a plastic sleeve over a metal interior. However, I
*have* seen a type that's just a metal sleeve. As far as I know, they are
intended only for joining bare ground wires.
Someone will stumble along here and claim otherwise, but I think electrical
tape is for slobs and hacks who don't know how to make a secure connection,
so they cover things up with tape to hide their incompetence. It also leaves
things gummy. When I want to rewire something, my definition doesn't include
wiping gunk off my fingers constantly because some monkey went nuts with
I once asked a local inspector and was told it was perfectly legal to use
crimps for house wiring, and was told that it WAS. There are two caveats:
1) You must use a crimp tool that actually shapes the crimp properly. You
won't find such a tool at Home Depot or Lowe's. It'll take some effort. It
requires a channel for the crimp to sit in, and a tooth-like prong on the
opposite jaw. The tooth almost creates a hole in one side of the crimp.
2) If wires might need to be disassembled later, and they're already short,
cutting off an old crimp will obviously make them even shorter. Use wire
nuts in these situations. Have several sizes on hand.
Wire nuts are perfectly fine; crimps aren't unless they're made properly, and
- no offense intended - asking the question shows that you don't know how to
make them properly.
It's "OK" in the sense that it is permitted by the NEC, although in my opinion
it should not be -- for exactly the reason you cite. It would be a good idea
to write a warning with a Sharpie on the inside of the cover plate.
Doug Miller (alphageek at milmac dot com)
I have a Gardner-Bender stripping/crimping/etc. tool that AFAIK is meant
for this job, and I believe I know how to use it. Asking whether it's OK
to do something has nothing to do, IMO, with knowing how to do it. There
are many possibilities:
1. I know it's OK and know how to do it.
2. I know it's OK but don't know how to do it.
3. I don't know whether it's OK and wouldn't know how even if it is OK.
4. I don't know whether it's OK but know how to do it.
I believe I fall into the last category.
Actually I suppose there are yet other possibilities:
5. I know it's not OK but know how to do it and will do it anyway.
6. I haven't a clue but will do it wrong even if it would be OK if I did
Tape is OK. I would use more that 3 layers. Be careful of points and
edges that can poke through the tape. It has to be listed electrical tape.
The crimps also have to be listed for purpose - including wire size and
number of wires, stranded/solid, and voltage for insulated crimps.
One more time: The tape is sloppy, and if the crimp is done right, there is
absolutely no need for it.
This company makes the best crimps you can buy:
On that page, you'll see a link to a pdf file which discusses proper
crimping tools and techniques.
Although you can order directly from the company, there may also be an
industrial supply dealer near you that sells their products.
These are the plain copper cylinders (more or less) that are crimped
onto the wires. As supplied, they have no insulation, so obviously if
they are used on hots or neutrals they need to be insulated afterwards.
What would you use other than tape -- or shrinkwrap, I guess?
Since the wrong kind of crimps were used, I would cut them out and change
them to insulated crimps. If you have the wrong connectors, you don't use
them and try and make them right. You stop the work until you have the right
thing. A cob job might be appropriate when making toast, but not when wiring
a house (or car, boat, or anything else).
Bare copper cylinders need to be insulated after they're installed, right?
One method would involve tape, which is sloppy and amateurish, and I don't
care whose grandpappy did it and got away with it. The other method
involves heat shrink tubing, which is miraculous stuff, but to use it
**correctly**, you should apply heat to all sides of the tubing. Not so easy
with short wires in a box.
No. I didn't say that. Wire nuts may be the only choice in a cramped box
where the wires are already too short for working with a crimper. But,
crimps are always the best way, when it's possible to use them.
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