Whenever I connect wires after using the wire nuts I wrap the nut and part of the wire with electrical tape thinking it is an extra safety precaution. I also wrap tape around the terminals of outlets/switches. Is this a good idea or am I asking for trouble. Also, I am concerned about arcing occurring under the wire nut should a wire loosen. Is this possible? And I understand that plastic wire nuts can melt, would this happen with ceramic nuts (and if not can I still buy them). Finally is there a electrical tester that can detect if a wire is prone to arcing.


thanks for taking the time to address my concerns but I just purchased a house approx 35 years old and I am paronoid of possible hidden electrical dangers especially involving connections.

P.S. I also read up on the AFCI's, but can they be used on multi branched circuits?
Dan

 

Most people will say not to tape wire nuts. If you need the tape to hold the wires or cover bare wire, you've made a bad connection and/or stripped off too much insulation. Plastic wire nuts are plenty safe and will not melt unless you have a bad connection which produces an abundance of heat. The best thing to do is make sure the wire nuts you are using are rated to handle the number of wires you've got in them. Make sure the wires have the correct amount of insulation stripped off and follow the manufacturer's recommendation on pre-twisting. Most say it's not required. Then tighten the nut up until you can't make it any tighter. Use good, name brand nuts, not something from an unknown manufacturer that came from the dollar store. I haven't seen the ceramic variety in the DIY stores, but maybe an electrical supply house might carry them. At any rate they are probably not necessary if your connections are properly made.

 

The tape or no tape debate has been raging for years, as has the pretwist or not pretwist the wire debate. Some do, some dont. I have been involved with wiring for 25 years, and I do not tape the wire nuts, nor do I pretwist them. The key is to be sure to use the proper SIZE wire nut for the number and gauges of the wires in the connection. Manufacturers usually list the recommended wire nut to use based on this.
If your house is wired with aluminum wire (which was the rage in the '60's), it's a whole other ballgame. I would then recommend you check each connection for tightness, corrosion, and signs of overheating. You might even want to have a licensed electrician go through and make sure everything is OK.
Good Luck

 

Oops!
I think Hotarc & I were typing our responses at the same time!
Sorry for the repetition!
Andy

 

Good point about the aluminum, Andrew. I didn't even think of that.

Wrapping the terminals on outlets and switches with tape is not a bad idea, but like taping the wirenuts, probably isn't really necessary. The arguments I've heard for taping terminal screws are:

1) So they don't short against the side of a metal box.

2) So a drywaller's metal tools do not come into contact with them.

So I guess it doesn't hurt to do it and only takes a few more seconds. I have done it when making up device connections in metal boxes, but not in plastic ones.

I guess the bottom line is, if it was really critical to ensuring safety, the NEC would probably require taping wirenuts and device screws.

 

I agree with the previous posts but I will stick my 2 cents in for the record. My belief is if the splice is made correctly there should be no need for tape. On the other hand it can't hurt anything. As for twisting the wires I am of the school that the wires should be twisted together. If you want to twist them you take all the stripped ends, hold them all near each other and take your lineman pliers and gently twist them. Wires of the same gauge will fall into place and make a neat splice. Then you give a couple of firm twists, cut off the excess and you have a perfect splice that fits perfectly in the wirenut.
As for taping the devices I do it for only one reason. So the next guy taking the device out doesn't get hit if he is a little careless.

Just remember the most important point in all this is that the connections are made secure and tight. Loose connections are what causes arcing.
Good luck

 

Thanks for your replies the wire I am dealing with is copper. I twisted the wires before I used the wire nut (14/2 wire) the one thing that concerns me is that there was some knicking from the lineman pliars. Do I now have to be concern about this!

 

Like lghtngbolt was saying, when you pre-twist, the best way is to strip off more insulation than needed, twist them together and cut off the part you nicked with the linesmans.

 

If you nicked the wires near the insulation when you stripped them then yes you should really do it over. When the wire is nicked and you twist it and then twist on a wirenut it tends to open the nick up and decrease the actual size of the wire. Invest in a wire stripper and you will avoid this problem.

 

Thanks again for advice however I believe I used the wrong wording instead of nicked I meant scuffed/scraped. When I used the lineman's when twisting the wire it left marks on the wire I was just concerned if these marks/scrapes weaken the wire.

 

The marks on wires shouldn't be a problem