I have a 20 amp breaker in my 1890’s home with 12 gauge wire attached to it. Further down the line (Where I can not see) there is some old 1960’s 14 gauge Romex wire attached to it within the walls of the house. This old 14 gauge wire is attached to a plug I want to tap into with 14 gauge wire to add a ceiling fan in my bedroom. Is this ok?

  • 3
    "attached to it somewhere within the walls of the house" I would recommend finding where this "somewhere" is. One would hope that the connection is at a switch, receptacle, fixture box, or junction box with a blanking plate. If it's truly "somewhere in the walls" then you've got another code violation and potential fire starter by having a wire junction either not in a junction box or the junction box not accessible for maintenance.
    – FreeMan
    Jun 25, 2020 at 13:08

4 Answers 4


Since your 20A circuit has 14ga wire attached to it, it's already illegal -- adding more 14ga wire to it won't change that situation as far as the code is concerned. But adding load to it may well start a fire inside your walls and burn your house down, since a 20A breaker or fuse can't properly protect 14ga wire. You're lucky in that it hasn't overloaded so far, but your new ceiling fan may well be the straw that breaks the camel's back.

To correct this problem, and make both your existing installation and your proposed extension legal and safe, you should change the breaker on that circuit to 15A.

  • 1
    It sounds like the 14ga wire is the final segment in that particular part of the circuit. In that case, there's not much luck involved -- it would take more than 15 amps plugged into the duplex outlet at the end of the circuit to overload the wire, and that's not something people do very often.
    – Mark
    Jun 25, 2020 at 22:21
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    @Mark But hoping it won't happen isn't sufficient protection. If you live alone and there are no neighbors close enough to catch fire from your property that's kinda morally OK. Otherwise it is just selfish.
    – Mołot
    Jun 26, 2020 at 12:01

Technically, no. 14ga needs to be protected by a 15A breaker, not 20A. Your choices are to replace the breaker with a 15A, find and replace the 14ga section, make an entirely new run for your new fan, or ignore it and take your chances*.

* Do not ignore it and take your chances.

  • 4
    It's against code and for safety reasons. You shouldn't be advising the OP to ignore and take chances. Just my humble opinion.
    – JACK
    Jun 25, 2020 at 1:35
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    @JACK I can see that last statement being sarcastic, but it's not quite as obvious as one might hope.
    – FreeMan
    Jun 25, 2020 at 14:11
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    It was sarcastic, but also an acknowledgement that people often chose to ignore things like that regardless of better advice because they don't want to spend the money to do it right, so I wanted to ensure that he knew he was taking chances by doing so.
    – JRaef
    Jun 25, 2020 at 17:06

No, that is not ok. You may not have 14Ga copper (or 12 Ga aluminum) downstream of a 20A breaker/fuse. All the wiring downstream of a 20A breaker/fuse must be 12 Ga copper or larger (10 Ga or larger for aluminum).

  • Thanks for your responses everyone. I didn’t think so. I’m bothered by the fact that the old 14 gauge wiring attached to my plug is on the 20 amp breaker. I think I should disconnect that plug and cap the wires? It’s been like that for probably 50 years. Thanks
    – Bill C
    Jun 25, 2020 at 2:05
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    Or just change the breaker to 15A. Jun 25, 2020 at 15:24

Some allow for prior use but it is a touchy subject. If you have a history, fairly long and not between various users, under 20 amp breaker with 14 gauge wire, there is not a major problem if you do not change your current use??? Best to change all of the wiring in the circuit or change the breaker to 15 amp. I am trying the “all the wiring” but it is a chore fishing the wiring, not so bad, I suppose, but some of the metal boxes don’t like the tolerance of the twelve wiring, so use a plastic box when you get to ground arcing

  • 2
    "Some allow for prior use" where "some" does not include the NEC, on this subject. Apart from leading with that statement, this is not terribly clear and could stand some editing.
    – Ecnerwal
    Mar 8, 2022 at 21:58
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    Why does your second sentence (clearly a statement), have question marks on it? Please see How to Answer and take the tour to learn more about this site.
    – isherwood
    Mar 8, 2022 at 22:07
  • Not sure at all what "use a plastic box when you get to ground arcing" is supposed to mean.
    – FreeMan
    Mar 9, 2022 at 15:50

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