Question about wiring

[xli1]

Just wondering to obtain 30Amp current, instead of using #10 wire (30 A), can you just use two #14 wire (15 A) in parallel? This sounds wired, but I am very interested to know.

[LCHIEN]

Just wondering to obtain 30Amp current, instead of using #10 wire (30 A), can you just use two #14 wire (15 A) in parallel? This sounds wired, but I am very interested to know.

technically, that's quite alright to do, It will in fact provide twice the copper path and reduce the resistance to half of what one wire provides. so the voltage loss and individual wire heating will be the same as using the bigger gauge wire.

I'm not 100% sure its legit to do that for household wiring, though.
probably for the reasons it may be harder to terminate the lines and failure of one of the parallel lines to be connected will be hard to detect but could lead to fire.

Maybe someone else can tell if the NEC codes allow such a thing.

[sd]

This is not allowed by the NEC. See 310.4, Conductors in Parallel.

[gjat]

Don't do it. If one conductor is lost, you'd put too much load on the other and the wire would be weaker than the breaker...

Do not do the electrical work if you ask a question like that. Spend a few bucks and get an electrician to look at the job, and tell you what he would do. THEN decide if that is something you want to tackle or do part of the labor for a lower bill. Saving $100 bucks in wire or electrical material doesn't seem worth risking burning your garage down, starting a fire in your basement, or killing yourself and your family due to an electrical fire.

Plumbing is for do-it-yourself people, not serious electrical work.

[p8ntblr]

Ditto. for the reasons gjat explained

[scorrpio]

Plumbing is for do-it-yourself people, not serious electrical work.

Hey! If you think 500 gallons of sewage in your basement or water heater explosion are fun, you should try it sometimes. And gas piping is also considered 'plumbing'. Serious plumbing demands at least as much respect as serious electrical work.

[crokett]

That is a very bad idea. Buy the #10 wire.

[mpc]

Parallel wires will not share the load 50-50 either. Remember, all wires and connections have some resistance (forget about science lab superconductors refrigerated to near absolute zero... I don't have those in my house, do you?). And those two parallel wires won't have identical resistances. So the one with higher resistance will "take" a bit less of the load... e.g. a 30 amp load split across two 15-amp rated wires might split at something like 14 and 16 amps. Now one wire is overloaded.

This same thing happens when trying to parallel two transistors to handle big loads. The solution there: add a little resistance in the base-emitter circuits of each transistor to reverse-bias the transistor (i.e. tries to turn the transistor OFF a litttle bit) which ends up getting the two circuits fairly well balanced. Unfortunately, you can't do that with plain wires - you need transistors.

mpc