Maybe a reader or two can email this guy with advice.


----- Original Message -----
From: "TomVote" <TomVote@Hotmail.com>
Newsgroups: alt.engineering.electrical
Sent: Sunday, September 15, 2002 11:29 AM
Subject: Melted Wire Nuts

> This group seems to have a good sense of humor and tolerance for novices. I appreciate that.

> Have a problem with a cira 1970's 120v line (12-2g) running underground (40' tops) to a swimming pool pump. Had to replace the pump and decided to wire the outside switchbox to the pump with 12 guage instead of the 14 that was on it. Pump is 1hp 15 amp. Replacing the light switch (15a) that was in the box with a GFCI was a disaster, kept tripping the GFI, sometimes immediate and sometimes after the pump ran a few minutes. Decided to go without the GFI till I can get an electrican out to do everything right.

> So a pair of 12 guage being tough for an amateur (and weakling) like me to handle, I used large (red) wire nuts to make the direct connection in the box. Even went so far as to throw one on the groud wires to be sure they stayed connected. Shoved everything in the box and covered it with a metal blank face plate. Box is covered properly for outdoor use BTW, but I didn't check how I shoved the connectors in, sloppy.

> Pump ran for three or four days, then stopped. When I took the cover off the box, the wires were burned and the wire nuts were melted. Appears (can't be sure) that the ground came near, or in contact with the hot.

> Now the questions. The 20 amp circuit breaker never tripped. Shouldn't it have, with enough current flowing to generate the heat to melt the wire nuts? Redid it yesterday with medium (yellow) wire nuts, which I originally ignored because they looked to small. Packages for both large and medium list two 12 guage as acceptable. Any difference between using large or medium in this type of application?

> Thanks for any insights you can provide.

> Tom




[This message has been edited by Bjarney (edited 09-15-2002).]

****Note to Self****

Don't go swimming in Tom's pool.

Everybody knows that red wirenuts are hot already and are about to melt right out of the box, thats why they're red. Now a blue wirenut runs much cooler and matches the color of the pool water. That would have been obvious to me.


[This message has been edited by arseegee (edited 09-15-2002).]

I'll keep the sarcasim and humor to myself, hard as it may be:
IF the "hot" touched the ground, the circuit breaker should have tripped.
Perhaps the "connections" within the wire nuts were not made correctly, and arcing occurred, causing excessive heat, melting or burning the "splices"????

Do yourself, your family, and any friends that you invite to your home a faver; CALL A Professional!!!

Enough said
John

Tom:
I agree with John in the strongest possible terms here. Electric current and water are potentially a very lethal combination. Speaking strictly out of concern for you and your visitors, PLEASE, PLEASE turn this job over to a licensed professional, and preferably someone who has a considerable amount of experience in this particular phase of electrical work. Your life and the lives of your friends are certainly worth it.

Mike (mamills)

Thats just the left over factory smoke coming out of the motor, and the wirenuts . the wirenuts melt to form a protective seal around the joint.
bzt....ZZZZZZZT....*poof*.
seriously, kill the power, call an electrician.

You should have shut off the power and call a Pro when you couldn't get the GFCI to quit tripping. That was your first clew, the second is Reds are too big to secure 2, 12 gauge wires, you should have used yellows from the start. If the wire nuts were put on correctly the ground shouldn't have been able to contact the hot at the wire nut.

It is time to spend a little money and be SAFE!! Call in a good pro that is experienced with pool wiring.

Kind of sounds like the connections inside the wirenuts were loose.

Another reason to pretwist!!!

Scott S.E.T.

Scott,

You bring up a good point about pretwisting.
My handbook shows an illustration of 2 wires not twisted to be connected to a wirenut.
I was always taught the connection has to be mechanically secure and the wirenut was just to maintain, not make the connection (in other words, twist them together).
Anyone want to elaborate on 110.14 (B)

The following pix show three different techniques for installing wirenuts.

All pix use 2 #12 AWG Solid Conductors from NM-B Cable, the contrasting black and white colors to illustrate the twisting.

The first two pix show the connection made by pretwisting and trimming the conductors, then installing the wirenut hand tight.





The second pair of pix shows using no pretwisting, but using the Ideal WireNut wrench.





The last pair shows the technique of using Wingnuts tightened hand tight, and no pretwisting.





All wirenuts were removed to show the quality of the connection, and the number of twists in the conductors.

Any comments?

(I know this is old hat to most of you, I did this a year ago, but I got a macro camera now!)

It looks to me like the Ideal Tan Twister wire nut by hand provided the best connection. If I'm only putting 2 or 3 14's or 12's together, I use the tans by hand, but if I have more than 3 wires I use my Kliens to make a good twist. Also if I'm making up lots of boxes or cans, I use the tans with a drill driver for speed. I've checked the connections and they are as good as it gets.

Pre-twisting is not required if the wirenut is installed properly. The wires will be twisted as the connector is applied.

In fact, the wires will conform to the tapered shape of the internal thread in the wirenut better if they are not pre-twisted, and as a result, more threads will be engaged.

Ed

Ooops, you're right... A Twister not a Wingnut...

Thanks for the enlightenment.
The pictures really drove home your point.
I have always used my Ideal's to twist the wire and after getting the wirenut tight, I would put a couple of wraps of tape to bond the nut to the insulation. Thanks for taking the time to post these pictures!

Thanks, currently...

Sometimes I do "go beyond the call of duty" (or as some may say "gone too far"...)

electric-ed, in an old thread lost in cyberspace, I tried in vain using about a million words to say just what you did.

Thanks!

(No offense, Scott35!)



As may be obvious from the neatness of the job, the 2nd pair of pix is what I do the most often. I was actually surprised that the Twister performed this well, as I've had trouble with them in the past holding as well as the standard yellows.

I finally musta done it right!

My partner Joe drove the spring right out the small end of a Twister the other day using some serious torque. I've had copper protrude from the yelllows when all the conductors don't line up straight.

I guess it all comes down to the quality of the technique rather than the technique itself...



[This message has been edited by sparky66wv (edited 09-24-2002).]