Tightening Wire nuts /nut sizes

Discussion in 'Electrical Forum discussion & Blog' started by molo, Aug 17, 2007.

  1. molo

    molo New Member

    Messages:
    840
    Location:
    cold new york
    The back of the wire nut boxes are very confusing, with several numbers. How do you know what wires will fit?
    Also, how do you know when the wirenut is tight enough? are you supposed to use a tool or just your hands?

    TIA,
    Molo
  2. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    It depends on the number of wires and their gauges. If the wire nut is too small, the wires won't fit inside. If the wire nut is too large, the wires can pull out easily.

    Just hand-tighten them and then wrap some electrical tape around the opening.
  3. frenchie

    frenchie Jack of all trades

    Sparkies - cleanup in aisle three!


    I'm not sure about the details, so hopefully a real electrician will swing by. But as far as I know, it's supposed to be pretty tight. Electricians do it by hand, but they really crank on those suckers. Not finger-tight, forearm tight.

    Electrical tape over a nut is a nice gesture: it gives fair warning to the next guy.

    As for which nut to use, that's what those numbers on the back of the box are for: all the combinations of wires that nut will hold. So many of this size, so many of that size, etc.

    Yellows & reds cover most household needs.
  4. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    Nicely Put Frinchie
  5. molo

    molo New Member

    Messages:
    840
    Location:
    cold new york
    1. i've heard the tape was the sign of an amateur

    2. There are 20-30 nsets of numbers on the boxes

    3. Yes i ususally use red or yellow

    4. Is it causing a problem with over-heating if you tighten them to the point that the wires coming into the nut begin to twist?

    TIA,
    molo
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    No...I like to pull individually on each wire after I get a nut installed to make sure something didn't slip. Probably the worst thing in this situation is a loose connection.
  7. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    No tape is needed if the wire nut is installed propertly
    I twist the nut until the conductors are twisted at least twice on the outside of the nut
  8. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    Inside joke?

    No wonder I'm not an electrician. I have to use my fingers to tighten the nut. They must have specially designed forearms that grab on to it and really crank it tight. :D
  9. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    [​IMG]

    As you can see that the electricians forearm has some interesting aspects that are internal to the arm itself :D :D
  10. frenchie

    frenchie Jack of all trades

    Verdeboy -

    Inside joke? I thought it was pretty obvious. ;)

    Ha-ha on the forearm joke. But when you crank on something really hard with your hands, the forearm muscles come into play... all I know is that, when he's tightening wire nuts, sparkie's elbow moves. He's putting his whole arm into it.

    Seriously - if you're going around twisting wire nuts just hand-tight, you're going to get a lot of call-backs for loose connections... if you're lucky. If you're unlucky, the results might be a bit worse than that.


    (Side-comment... just so you don't think I'm all Joe T on you) Lesson #1, if you're working outside the law, is to make sure your work is perfect. "As good as most" doesn't cut it, and "good enough" is just out of the question. It has to be better than any pro's. If something goes wrong, a licensed/insured guy's butt is covered, to some extent. But if you're being Harry Tuttle, they're out to get you already. You have no safety net, you can't afford a mistake, you are completely on the hook if something goes wrong. Cover Your Ass, bro... learn up on this stuff.


    Molo -

    The danger of overheating is if you don't tighten them enough. Loose connections = arcing = fire hazard. As long as you don't go tight enough to damage the wire or the nut (I think this is why they don't use tools to tighten the nuts)... the tighter the better.

    And yeah, electrical tape is the mark of an amateur. Not to take cheap shots, but if you're going to leave nuts insufficiently tightened, then it's a good idea, as it does give the next guy fair warning that an amateur's been at this wiring.
  11. kd

    kd New Member

    Messages:
    207
    The connection should be mechanically secure, twisted with pliers, prior to the application of the wire nut. Then finger tight is OK
  12. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT

    Not true, read the directions that come with the wirenut... Pre twisting is not required, but feel free to do so.
  13. crutch

    crutch New Member

    Messages:
    5
    Location:
    michigan
    i always recommend twisting of solid conductors i.e romex but in commercial uses we use alot of stranded wire and it's not necessary to twist them. for some reason the wn just don't bite as good on solid wire.
  14. seaneys

    seaneys New Member

    Messages:
    192
    Location:
    Chicago Suburbs
    You also have to watch the difference between wing nuts and wire nuts. I like wing nuts much better. You can also get one more 12ga wire in some of the wing nut brands than in the normal wire nuts.

    A little trick I have found is to use stranded wire. I have a hard time getting the torque I need to feel confident in tieing 3 or 4 12ga wires if they are solid.

    I'm not a pro...

    Steve
  15. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    Haven't had a call-back yet. I think you're splitting hairs a bit. Molo just wanted to know "hand-tight vs tool." Consensus is hand-tight.
    So, you're a GC and an expert on New Mexico law?

    Geesh. I guess I better start training for the world wire nut competition...and win...if I'm going to keep installing those light fixtures and receptacles.:D

    Duuuh. That's why I keep posting all of my "rookie questions."

    I've seen plenty of wiring done by electricians, where a bit of electrical tape is used to cover the open end of the wire nut. It serves 2 purposes: The first is an insurance measure against wire pull-out. The second is to seal the connection in the unlikely event that water gets in there, from a roof leak, etc...
    Last edited: Aug 18, 2007
  16. frenchie

    frenchie Jack of all trades

    These days I'm a caretaker, and a project manager. I used to GC, small-time, pretty much a one-man-show. Before that, I was an unlicensed handyman.

    I looked up the NM law; it wasn't hard. I don't need to be a legal expert to understand that, anywhere they have licensing laws, operating outside them makes you the easy scapegoat, for everybody else, if anything goes wrong.


    Just because you aren't being called back, doesn't mean someone else isn't being called to troubleshoot your work.


    I've never seen an electrician use tape, and I've heard their comments when they see tape on a nut. It's the mark of an amateur. By all means, carry on; it narrows down the troubleshooting process for the guys who come later.

    But it offers almost no resistance to pullout (try it: put a wire nut loosely on a splice, tape it, and pull).

    And a connection being loosely held together will still arc... will they care that the lights still work as their house burns down?

    It definitely won't seal against water (again, try it)! BTW, they make special wire nuts for wet locations. And you should be installing any wire nuts at risk of water, pointing up, so water can't run down into it.
  17. Old Dog

    Old Dog G.C. 22+ years(in 3 states)

    Messages:
    82
    Location:
    Hawaii
    Good housekeeping...

    Hey Eric,you got to expect to catch a little heat from the "Fellas" when you post something thats not a standard practice within a certain trade.The sparkys didn't say you couldn't do it,just that it's a dead giveaway that your not well versed with everyday practice.(some of the stuff sparky's do is kin to a secret handshake between them.)It has been my experience with most Electricians, (because of the potential dangers of their trade) preform "good housekeeping" when it comes to the inside of the boxes.tight wn's,tightening down unused screws on plugs,no tape,right length of wire(DIYer's and inexperienced people almost always cut wires way too short!!)
    When they don't see it done this way or here someone who gives contrary info they are gonna jump on you like stink on S***!
    Have you ever witnessed an electrician,after trimming out a new house go around with a straight slot and adjust all the screws on plates so they are all straight up?Thats the type of universal attention to detail sparky's bring to their trade whether it's here in Hawaii or on the East coast.
    IT's important to know the jargon...no matter what trade your dealing with.
    To gain respect you got to show respect.
  18. seaneys

    seaneys New Member

    Messages:
    192
    Location:
    Chicago Suburbs
    The book:
    'Wiring a House' by
    Rex Caudwell

    Has a great section on installing wire nuts.

    I actually hadn't read it, but I was surprised to see that he suggests pre-twisting.

    Steve
  19. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    That's exactly my point, too. It bugs the crap out of me when people put down other people and try to put them in their place, rather than simply sharing knowledge and trying to elevate others to a higher level.
  20. frenchie

    frenchie Jack of all trades

    Fair enough - you keep catching me late at night, when I'm tired...

    But "hand-tight" was misleading, and the tape thing's just plain wrong.

    I'm not supposed to give you flak when you post a wrong answer? Don't talk out your ass, I won't diss you.

    The rest was a friendly warning, even if you don't take it that way.
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