Correct wire??

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Old 11-08-04, 07:24 AM
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Correct wire??

I'm adding a couple of outlets in the attic. Someone has already pulled wire from the box up to the attic. I have traced down the wire and there are a couple of outlets on it now. The wire from the box looks like 12/2 and the wire going to the outlets looks like 14/2. Is this the correct wire to use to run new plugs..14/2???
 
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Old 11-08-04, 07:32 AM
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14 ga. wire can only be used with a 15 amp breaker. If your breaker is a 20 amp you will need to change the wire to 12 ga. or change the breaker to a 15 amp.
 
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Old 11-08-04, 07:41 AM
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As has been stated, 14 guage wire requires a 15 amp breaker. If the breaker is a 20 amp breaker then I recommend changing the 14 guage wire to 12 guage wire, rather than changing the breaker to a 15 amp breaker which is your other alternative.

Many people, myself included, don't recommend mixing wire guages on a circuit like this, as it just confuses people in the future when additions or changes need to be made.

Several other cautions. Make certain that the wire in place is three conductor, meaning two shielded conductors plus a ground. If the wire is old style where there is no ground then do not use the circuit at all, but rather run new wire.
 
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Old 11-08-04, 08:35 AM
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Thanks

Thanks guys. This is new wire run straight from the box. The breaker is a 15 amp and like I said it looks like they ran 12 wire to the attic and then ran 14 out to the plugs. So I need to change the breaker to a 20 amp and then change the wire going to the plugs to 12/2...is this correct??
 
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Old 11-08-04, 09:02 AM
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If you have a 15 amp breaker then you can use the 12 guage wire. I wouldn't do this (normally), but it does meet code and is safe.

If you want to put in a 20 amp breaker, then remove all the 14 guage wire and replace with 12 guage and you will be fine. If you do leave the 15 amp breaker in place, then I would at least make a note in the panel that there is 14 guage wire on the circuit, so someone doesn't see 12 guage wire and think they can upsize the breaker.
 
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Old 11-08-04, 09:04 AM
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Please confirm that I understand the situation correctly:
12ga wire from breaker panel to first receptacle
14ga wire between receptacles
15A circuit breaker.

If the above is correct, then you have a safe and legal installation. The circuit breaker must be sized for the smallest conductor in the circuit, but larger conductors are allowed as long as they are correctly installed with respect to things like terminal size, box fill, conduit fill, bending radius, etc.

As racraft notes, the mix of 12ga and 14ga wire _may_ cause confusion, however there are sometimes good reasons for mixing wire sizes.

For example, longer runs of wire can result in 'voltage drop', and thicker wire is used to mitigate this problem. On the other hand, smaller wire is easier to work with, and better fits into boxes. So the combination of thick wire for the main run back to the panel, with thinner wire for the short runs between receptacles makes very good sense in some situations.

I'd recommend leaving well enough alone, making a note on your circuit map that this circuit contains 14ga conductors.

-Jon
 
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Old 11-08-04, 09:13 AM
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Jon...you are correct. The wire in the attic is just tacked to the rafter beams and not threaded thru the beams. Since I am finishing the attic I need to pull all of this wire out and run it thru the beams. Since I have to do this and some of the runs will be long...then I think the best thing to do...if I am reading you all correctly...would be to put a 20 amp breaker in the box and run 12/2 wire???? Correct??
 
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Old 11-08-04, 09:19 AM
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If you have to redo the wiring anyway I would certainly use 12 guage wire. Voltage drop does not really become an issue unless you start getting into the hundreds of feet. In a normal single family residence this is not an issue.
 
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Old 11-08-04, 09:26 AM
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You should double check 'box fill'. Use the forum search tool to find out more about this. There are rules about how much of what size wire may be in a receptacle box, and increasing the wire size may bump you into these rules.

But if the box fill checks out, then since you have to take the wire out anyway, I agree with racraft: go for the #12 wire.

-Jon
 
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Old 11-08-04, 09:27 AM
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Thanks....I guess I know what to do know. Thanks to everyone.
 
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