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Ok to mix 12/2 and 14/2 wire to a 20 amp breaker or 15 amp breaker?

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Ok to mix 12/2 and 14/2 wire to a 20 amp breaker or 15 amp breaker? chrisc 05-07-2008
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Posted by hallerb@aol.com on May 8, 2008, 9:13 am
So its not legal too put a 10 gauge wire on a 20 amp breaker?

I have done that on a long run to my shed, to minimize voltage drops
on a outlet servicing my table saw.

thought that was is legal?

Posted by on May 8, 2008, 9:55 am
On Thu, 8 May 2008 06:13:21 -0700 (PDT), "hallerb@aol.com"

>So its not legal too put a 10 gauge wire on a 20 amp breaker?
>
>I have done that on a long run to my shed, to minimize voltage drops
>on a outlet servicing my table saw.
>
>thought that was is legal?

It is, the only restriction is on the minimum size (240.4(D))

Posted by Chip C on May 8, 2008, 10:44 am
> So its not legal too put a 10 gauge wire on a 20 amp breaker?
>
> I have done that on a long run to my shed, to minimize voltage drops
> on a outlet servicing my table saw.
>
> thought that was is legal?

Yes, it's code-compliant, and very common.

The only restrictions would be whether the device can safely accept
the wire. Like, some 15A-rated switches and outlets might not accept
very heavy gauge wire on some of their terminals; the obvious fix
would be to pigtail to a lighter gauge in the device box. Of course,
the lighter gauge now restricts your breaker ampacity, but so does the
rating for the switch or outlet.

Chip C
Toronto

Posted by terry on May 8, 2008, 4:22 pm
>
> > So its not legal too put a 10 gauge wire on a 20 amp breaker?
>
> > I have done that on a long run to my shed, to minimize voltage drops
> > on a outlet servicing my =A0table saw.
>
> > thought that was is legal?
>
> Yes, it's code-compliant, and very common.
>
> The only restrictions would be whether the device can safely accept
> the wire. Like, some 15A-rated switches and outlets might not accept
> very heavy gauge wire on some of their terminals; the obvious fix
> would be to pigtail to a lighter gauge in the device box. Of course,
> the lighter gauge now restricts your breaker ampacity, but so does the
> rating for the switch or outlet.
>
> Chip C
> Toronto

The idea of using heavier gauge to minimize voltage drop on a longer
run sounds like a good idea for some situations. In our case a shed
about 50 feet from far end of house. But so far we have never had
anything heavier than one light bulb and a small electric drill
plugged in out there.

Understand that you can use a 'heavier' wire, as long as it will fit
properly into terminals and switch and outlet connections. But not use
a lighter gauge than allowed.

General rule (domestically) being;
Any 14AWG in a circuit, maximum breaker rating is 15 amps.
If circuit is all 12AWG maximum breaker rating is 20 amps.
Correct?

Case in point; extended a spur from an outlet circuit through an
outside house wall to an attached shed for one lamp and a single GFI
duplex outlet, from a #12AWG 20 amp breakered circuit. Couple of days
later realized that the length of metal armoured cable (3 wire) used
through outside wall of house might be 14AWG.
It was! So promptly changed the circuit breaker for that whole circuit
to 15 amp.

All correct?

Posted by Harry K on May 8, 2008, 9:52 pm
>
>
>
>
>
>
>
> >> The wiring is all over the place in this house. For example a bathroom
> >> fan is on 14/2 wire going to a 15 amp breaker. And a bathroom outlet
> >> is 12/2 going to a 20 amp breaker. I want to put both on the same
> >> circuit and make everything more neat and organized. Which breaker can
> >> they not go on if combined? Can't remember how the rules go. Is one
> >> unsafe cause the wires can get too hot. Thanks a lot.
>
> > Wiring is supposed to be all over the place...better know as distributed=

> > based on probable use. The bathroom is on 20A because of the electric
> > hair dryer and curling iron plugged in is sucking a lot of juice. This i=
s
> > not an unlikely event.
>
> > 1875w hair dryer 15.6A
> > Curling iron maybe another 1A
>
> > Put the toilet fan and light on it and a light strip and...
> > Toilet fan & light another 1A
> > 4 light BR vanity strip 60w each another 2A
>
> > Pushing the 20A now. Not so neat.
>
> > Not a freak thing to have all this on at once.
>
> The wiring sounds perfectly normal to me. If the house is fairly new, the
> code allowed for the lights and fan to be on any general lighting circuit
> and the required 20 amp GFCI protected outlet, to be on the same 20 amp
> circuit as the outlets in the other bathrooms
>
>
>
> - Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

The wiring as it is originally is code compliant. What he wants to do
is not. He wants to mix 14/2 and 12/2 on a 20 amp breaker - that is
not code compliant.

Harry K

Page 4 of 4       << first < 1 2 3
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