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William
Best way to extend wires?

I'm installing a new light switch and box. The new box is slightly deeper than the old one and now the wires don't reach the switch, so I need to extend them around 6 inches. What is the best way to extend the wires, solder and heat shrink, twisted wire connectors, or are both OK?

Thanks...

sparky1
Re: Best way to extend wires?

You said reach the switch. Im hoping you at least have the wires in the electrical box??? assuming you do, if you can get wire nuts on em, thats what I'd do. also hopefully you have the outter sheath inthe box like a 1/4", If not id prolly heat shrink that to make the box.

canuk
Re: Best way to extend wires?
MyMilan wrote:

I'm installing a new light switch and box. The new box is slightly deeper than the old one and now the wires don't reach the switch, so I need to extend them around 6 inches. What is the best way to extend the wires, solder and heat shrink, twisted wire connectors, or are both OK?

Thanks...

Soldering is not allowed.
Use the same gauge wire ( sometimes called pigtails ) with wire nuts.

dj1
Re: Best way to extend wires?

If you use wire nuts, make sure they are located in the old box and are covered and accessible. From there run your new wires to the new box.

William
Re: Best way to extend wires?
sparky1 wrote:

You said reach the switch. Im hoping you at least have the wires in the electrical box???

Yes, but I can't get my hands in there to make the connection :D

I am heat shrinking as much as possible, even if it doesn't look like it needs it. Eventually I will be replacing the wire all the way to the box, but right now I'm really strapped for money. I had to pay for two funerals recently and those cost a LOT of money:( I am also thinking of using shallow boxes to help. Fortunately these switches are very thin, around 3/4 to 1 inch thick, so the shallow boxes might be all I need.

canuk wrote:

Soldering is not allowed.

I noticed this but I don't understand the reasoning why. I used to wire up police cars and ambulances and you HAD to solder every connection because they said it was the best and most secure connection possible. I would think that would also be a good thing for house wiring. Does anyone know the history behind not allowing soldering and heat shrinking, or what the "reasoning" is behind it? It certainly seems like a much better connection than those plastic pigtails. I will use the pigtails because that is what code calls for but I am really interesting in the reasoning behind not allowing soldered wires if anyone knows....

William
Re: Best way to extend wires?
dj1 wrote:

If you use wire nuts, make sure they are located in the old box and are covered and accessible. From there run your new wires to the new box.

Are you saying that I should tuck the old box behind the wall and run the new wires from it to the new box? Wouldn't that put unneeded strain on the old wires from the weight of the metal box? :confused:

canuk
Re: Best way to extend wires?
MyMilan wrote:

I noticed this but I don't understand the reasoning why. I used to wire up police cars and ambulances and you HAD to solder every connection because they said it was the best and most secure connection possible. I would think that would also be a good thing for house wiring. Does anyone know the history behind not allowing soldering and heat shrinking, or what the "reasoning" is behind it? It certainly seems like a much better connection than those plastic pigtails. I will use the pigtails because that is what code calls for but I am really interesting in the reasoning behind not allowing soldered wires if anyone knows....

Solder melts at a low temperature --- consider a pencil soldering iron is only 24 -40 watt.
Knob & tube splices are soldered and that's one weak area which makes that type of wiring flakey.
When folks would over amp the lines the solder would heat -- melt and the splice would loosen. Once the splice loosens this causes arcing which not only causes more overheating but also the sparks can ingnite surrounding combustionables.

Leave the solder and heatshrink for low voltage wiring.

dj1
Re: Best way to extend wires?

If you tuck the old box (with the wire connections in it) behind the drywall - it's not accessible.

I've seen it done many times, but it's not to code in my city.

canuk
Re: Best way to extend wires?
MyMilan wrote:

Yes, but I can't get my hands in there to make the connection :D

I am heat shrinking as much as possible, even if it doesn't look like it needs it. Eventually I will be replacing the wire all the way to the box, but right now I'm really strapped for money. I had to pay for two funerals recently and those cost a LOT of money:( I am also thinking of using shallow boxes to help. Fortunately these switches are very thin, around 3/4 to 1 inch thick, so the shallow boxes might be all I need.

The box size will be determined by the * fill * requirement

William
Re: Best way to extend wires?
canuk wrote:

Solder melts at a low temperature --- consider a pencil soldering iron is only 24 -40 watt.
Knob & tube splices are soldered and that's one weak area which makes that type of wiring flakey.
When folks would over amp the lines the solder would heat -- melt and the splice would loosen. Once the splice loosens this causes arcing which not only causes more overheating but also the sparks can ingnite surrounding combustionables.

Excellent explanation canuk! THANK YOU :) That actually makes sense with the wires heating up, but then why do they allow wires run inside studs? Is the new insulation more heat resisitant?

dj1 wrote:

If you tuck the old box (with the wire connections in it) behind the drywall - it's not accessible.

I guess what I don't understand is why not just make the connections in the new box? Why use a second box? :confused:

Fencepost
Re: Best way to extend wires?

Too bad these have been discontinued, they'd be "Ideal" for your situation:

http://www.idealindustries.com/prodDetail.do?prodId=30-3181&div=0&l1=twist-on

I don't know why soldering is no longer permitted by the National Electrical Code, but I do belive that it is not permitted in aircraft because soldering changes the temper of the wire, which could lead to metal fatigue and failure when exposed to the constant vibration that aircraft experience.

(Canuk, they are only listed as 'discontinued' on the US site. On the Canadian site, it doesn't say 'discontinued.' Maybe you could start a graymarket trade sending those things to DIY'ers down here in the states!)

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