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TallPaul · 06-26-2007, 07:50 AM

I ran the air conditioner on the generator and after about 25 minutes smelled melty plastic. Shut it down. Later at the campground I ran the air con with the land line plugged in and it didn't smell like melty plastic.

Went into the top of the electrical center (with it unplugged and the gen off) and opened the electric box that is part of the generator automatic switch. I found a badly melted wire nut on the neutral line from the generator where it connects with the wire to the switch.

It appears as if it was not properly assembled in the first place because the stranded wire to the switch was mostly out of the nut, but the solid wire from the generator was solidly in the nut. I cut back past the burnt part and restripped the wires. Used one size smaller wire nut and it went on fairly easy but tightened up good.

Ran generator for 2 hours and felt connection. It was fairly warm, but not hot. It bears watching, but seems like it will be okay. Not sure if it is hot because of being on top of the electrical center, or because of the wire gauge, which looks like a #12 coming in from the gen and is thicker in the stranded wire to the switch. I would think a #10 would be better.

At any rate would it be normal to generate some heat during air con operation on high?

TallPaul · 06-26-2007, 07:50 AM

I ran the air conditioner on the generator and after about 25 minutes smelled melty plastic. Shut it down. Later at the campground I ran the air con with the land line plugged in and it didn't smell like melty plastic.

Went into the top of the electrical center (with it unplugged and the gen off) and opened the electric box that is part of the generator automatic switch. I found a badly melted wire nut on the neutral line from the generator where it connects with the wire to the switch.

It appears as if it was not properly assembled in the first place because the stranded wire to the switch was mostly out of the nut, but the solid wire from the generator was solidly in the nut. I cut back past the burnt part and restripped the wires. Used one size smaller wire nut and it went on fairly easy but tightened up good.

Ran generator for 2 hours and felt connection. It was fairly warm, but not hot. It bears watching, but seems like it will be okay. Not sure if it is hot because of being on top of the electrical center, or because of the wire gauge, which looks like a #12 coming in from the gen and is thicker in the stranded wire to the switch. I would think a #10 would be better.

At any rate would it be normal to generate some heat during air con operation on high?

rclarke · 06-26-2007, 09:58 AM

A hot electrical connection is an indication of a bad connection (loose nut/poorly made connection in a wire nut). An undersized wire will also get hot.

Ray,IN · 06-28-2007, 01:16 AM

A solid crimped or soldered connection is best. Stranded and solid wires do not play well together in wire nuts, as rclarke said.

TallPaul · 06-28-2007, 02:58 AM

I'll see if I can get the crimping tool and bands (or whatever they are called, saw them in a hardware store the other day).

The solid wire is a #10 gauge. The stranded bundle is, of course, bigger, but I have no way to determine it's gauge. Would hope also #10.

John Hilley · 06-28-2007, 04:35 AM

I'm an electrician and the way to use wire nuts with stranded wire is to make sure you use a good wire nut with the coil inside and to strip the stranded wire about 1/8" longer than the solid wire, twist the strands of the stranded wire tight, then lay the two wires parallel with the stranded wire extending beyond the solid wire, then twist the wire nut on tight. Another good solution is Wago Wall Nuts

TallPaul · 06-28-2007, 07:45 AM

Thanks John,

As I found it, the bad connection appears to have been with the solid wire extending much farther into the nut. I have it now with them even.

I think I get the idea. Is it that you want the stranded wire longer so it is grabbed first by the wire nut, thereby ensuring that it does not get pushed back when the solid wire is grabbed?

Also, is it worth the bother to solder up the stripped part of the stranded wire after I twist it to help it retain integrety?

John Hilley · 06-28-2007, 09:22 AM

Actually the longer stranded wire tends to wrap itself around the solid wire as you twist the wire nut on. I wouldn't recommend soldering, with vibration and other factors, solder connections tend to crack and the resistance increases. Also trying to get the heat right with two wire types and sizes makes soldering difficult. You probably are thinking of tinning the stranded wire, that would probably be ok. I believe wire nuts are the best solution. I usually tightly tape the wire nut to the wire, wrapping in the same direction as you tightened the wire nut.

TallPaul · 06-28-2007, 02:14 PM

I re-did the connections. Found out the wire nuts I was using, size 6, which said for 2 #10 wires, were too small, prob because the stranded wire is a lot thicker. So I used a bigger wire nut and really cranked it on good. Will check heat next time I run air on generator. Also might as well check heat on other stranded line connections for the land line when running air on that.

Also solved my strange electrical problem in other thread (soluton there).

alvinc · 07-01-2007, 09:48 AM

Speaking of wire nuts, I prefer the 3M brand, if you don't want them to loosen or come off. A properly installed 3M wire nut cannot be removed. I can't tell you how many times I have used, or encountered them, and needed to take one off, and ended up cutting it off.

You can twist and twist, counterclockwise, and these suckers will not come off.

The only way I know to get them off is to cut them off. Either sacrifice some wire or actually cut the wire nut off. I usually have to cut the wire nut off, because I can't afford to lose any wire.

Using heavy side cutters, cut the tip of the wire nut off, then cut length wise so that the side cutters blades are parallel with the wire. The metal jacket is so tough I usually can't cut all the way through, but can get enough that I can worry it off. Often the wire spring will still be hanging on and its easy to get off.

What makes the 3M wire nut (oh boy I'm going to sound like a commercial, no affiliation though) better? Most wire nuts are plastic with a conical spring inside. The 3M has a conical spring surrounded by a tough metal shell, then finally a plastic cover. The 3M is also slimmer than the other makes (takes up less space in the box).

TallPaul · 07-03-2007, 02:53 AM

I don't recall seeing the 3M wire nuts. Are they readily available? I'll have to keep an eye out for them.

Paulin · 07-03-2007, 10:12 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">lay the two wires parallel with the stranded wire extending beyond the solid wire, then twist the wire nut on tight. </div></BLOCKQUOTE>
That is the way I was taught when I was an apprentice electrician. This is very common when attaching light fixtures to NM cable (Romex) in house wiring. Taping the wire nuts is a good idea in an RV and wherever vibration is a factor.

Paul