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 Calrob77 06-07-2012 12:33 PM

Twisting wire for higher voltage

First off, as you will soon see, I am not an electrician. I was having a discussion with a friend of mine about wire gage and capacity. If you twist the ends of say two #10 coated wires does that give you more voltage capacity that just one wire? Would it be advisable to do that if that was the wire you had available? Say you wanted to install a 30 amp circuit that was a 150 ft run and only had #10 wire.

 gregzoll 06-07-2012 12:41 PM

150feet 30amp, would work on #10. No problem about that short of length. It would even work with #12. The only thing that you did not state was the voltage. As for twisting, no it would not be needed, or something that you would want to do. They do do what you are stating for speaker wiring, but in turn, does not improve anything.

 joed 06-07-2012 12:49 PM

If you are talking about amps and not volts then using two #10 wires would allow more amps to be used. However the electrical code does not permitted using two wires in this fashion unless they are larger than #6.

 Calrob77 06-07-2012 01:13 PM

Thanks

Appreciate the info.

 Calrob77 06-07-2012 01:15 PM

Thanks. I thought that 150 feet would be too long of a run for #10 for 30 amp.

 mpoulton 06-07-2012 03:40 PM

Voltage rating depends only on the insulation of the wire, not the gauge or number of wires in parallel.

 stickboy1375 06-07-2012 04:14 PM

12 Attachment(s)
Quote:
 Originally Posted by joed (Post 938352) However the electrical code does not permitted using two wires in this fashion unless they are larger than #6.
1/0 AWG is the smallest size wire allowable by code to parallel.... 310.4

 stickboy1375 06-07-2012 04:15 PM

12 Attachment(s)
Quote:
 Originally Posted by Calrob77 (Post 938360) Thanks. I thought that 150 feet would be too long of a run for #10 for 30 amp.
It depends on the actual load.... it may or may not be.

 Yoyizit 06-07-2012 05:27 PM

Quote:
 Originally Posted by Calrob77 (Post 938341) If you twist the ends of say two #10 coated wires does that give you more voltage capacity that just one wire? Would it be advisable to do that if that was the wire you had available? Say you wanted to install a 30 amp circuit that was a 150 ft run and only had #10 wire.
With properly bolted or wirenutted connections at each end you should get almost half the voltage drop at any given current that you would get with a single #10, and the wires won't get as hot as a single conductor because you have more total surface area.

With imperfect connections your parallel arrangement will act like a single #10.

You can test this with a heavy load and voltmeter using an extension cord as a test lead.

The thing is, the smaller the wires used, the less important the connection integrity becomes, so I don't understand the NEC's reasoning in this case.

 stickboy1375 06-07-2012 05:39 PM

12 Attachment(s)
Quote:
 Originally Posted by Yoyizit (Post 938548) With properly bolted or wirenutted connections at each end you should get almost half the voltage drop at any given current that you would get with a single #10, and the wires won't get as hot as a single conductor because you have more total surface area. With imperfect connections your parallel arrangement will act like a single #10. You can test this with a heavy load and voltmeter using an extension cord as a test lead. The thing is, the smaller the wires used, the less important the connection integrity becomes, so I don't understand the NEC's reasoning in this case.
If the wires are not the same exact length is one issue....

 Calrob77 06-07-2012 06:09 PM

That is some really good information. I guess the question now is it alright to go 150 feet with #10 for 30 amps or should he maybe go with a 20 amp?

 stickboy1375 06-07-2012 06:18 PM

12 Attachment(s)
Quote:
 Originally Posted by Calrob77 (Post 938590) That is some really good information. I guess the question now is it alright to go 150 feet with #10 for 30 amps or should he maybe go with a 20 amp?
It all depends on the load.... and the maximum voltage drop you want to maintain.

If you want to go 150' and supply a full 30 amps at 120volts with a 5% voltage drop, you would need to run #6 AWG....

As a side note, the breaker stays the same, you only increase wire size to eliminate voltage drop.

 Calrob77 06-07-2012 06:26 PM

Good to know, thanks.

 rjniles 06-07-2012 06:29 PM

Quote:
 Originally Posted by Yoyizit (Post 938548) With properly bolted or wirenutted connections at each end you should get almost half the voltage drop at any given current that you would get with a single #10, and the wires won't get as hot as a single conductor because you have more total surface area. With imperfect connections your parallel arrangement will act like a single #10. You can test this with a heavy load and voltmeter using an extension cord as a test lead. The thing is, the smaller the wires used, the less important the connection integrity becomes, so I don't understand the NEC's reasoning in this case.
Regardless this arrangement is prohibited by code.

 micromind 06-07-2012 07:18 PM

Quote:
 Originally Posted by stickboy1375 (Post 938484) 1/0 AWG is the smallest size wire allowable by code to parallel.... 310.4
joed is from Canada; it may very well be different up there.

But yes, 1/0 is the smallest size allowed to be run in parallel in the USA.

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