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  1. #1
    Michael Vasquez's Avatar
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    Default 14 AWG and 12 AWG wire splicing

    I did an inspection today and the home owner has added recessed lights in the bedroom. He has spliced 12 AWG wiring with the existing 14 AWG wiring and are protected with 20amp breakers. Is this acceptable or should the breakers be 15amp which is the smaller size wiring?

    Thanks

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  2. #2
    Jim Zborowski's Avatar
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    Default Re: 14 AWG and 12 AWG wire splicing

    yep....15


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Michael Vasquez View Post
    I did an inspection today and the home owner has added recessed lights in the bedroom. He has spliced 12 AWG wiring with the existing 14 AWG wiring and are protected with 20amp breakers. Is this acceptable or should the breakers be 15amp which is the smaller size wiring?

    Thanks
    I'm not exactly sure what you mean:

    He had 14 AWG and spliced 12 AWG to it?
    He has 12 AWG and spliced 14 AWG ti it?

    He has (maybe) 20 amp breakers? That would suggest he has 12 AWG wiring to start with, not 14 AWG.


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Dom D'Agostino View Post
    I'm not exactly sure what you mean:

    He had 14 AWG and spliced 12 AWG to it?
    He has 12 AWG and spliced 14 AWG ti it?

    He has (maybe) 20 amp breakers? That would suggest he has 12 AWG wiring to start with, not 14 AWG.

    Dom,

    I'm sure you will agree, though, that regardless which way it is, the breaker needs to be a 15 amp, not a 20 amp ... to be rated to protect the smaller of the two wire sizes.

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    Default Re: 14 AWG and 12 AWG wire splicing

    It really makes no difference which wire is first, the overcurrent protection is for the smallest wire in the circuit.
    15 amp maximum for 14 gauge copper, maybe less if you have to derate it.
    Right Jerry?

    Jim Luttrall
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    Default Re: 14 AWG and 12 AWG wire splicing

    Jim is correct.

    It's like putting a fusible link into the line.

    Not to worry about the derating part either, you have to treat the entire circuit based on the highest ambient temperature, the greatest number of conductors not maintained spacing, the lowest temperature insulation, and the smallest size conductor.

    If one part of the circuit is in that 'condition', then the entire circuit is treated based on the worst case 'condition'.

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    Default Re: 14 AWG and 12 AWG wire splicing

    I asked for clarification because it was written in an unclear manner.

    If part of the information is vague, perhaps more of the information is missing or misstated.

    And...

    I'm sure you will agree, though, that regardless which way it is, the breaker needs to be a 15 amp, not a 20 amp ... to be rated to protect the smaller of the two wire sizes.
    That isn't exactly the ideal solution either; if the original breaker is a 20 Amp, with 12 AWG wire, then it would be better to re-wire the newly added fixtures with the appropriate size wire, then to assume facts that aren't clear.

    Your mileage may vary...


  8. #8
    Richard Pultar's Avatar
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    Default Re: 14 AWG and 12 AWG wire splicing

    The breaker must be a 15...The panel should be marked to identify that the 15 amp breaker is in place for a reason. It might help in the future .if for some reason ,after seeing the 12ga conductor it might get paired with a 20 amp breaker.
    A simple note on the panel...


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    Default Re: 14 AWG and 12 AWG wire splicing

    Is it correct to recommend the circuit be protected with a 15-amp breaker if it were originally protected with a 20?

    Are the number of outlets, lights, etc. determined by the circuit size at the time of construction (or, installtion of the given circuit)?

    Changing to a smaller breaker because someone wired something wrong seems to be treating the syptom rather than the disease.


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Dom D'Agostino View Post
    That isn't exactly the ideal solution either; if the original breaker is a 20 Amp, with 12 AWG wire, then it would be better to re-wire the newly added fixtures with the appropriate size wire,
    I agree that "it would be better to re-wire .. with appropriate size wire", however, ...

    then to assume facts that aren't clear.
    The facts *were* clear: the facts were presented that there were two sizes of wire in a single circuit, and, given those facts *as presented*, the *IMMEDIATE SOLUTION* is to install the proper overcurrent protection - ASAP!, - and until that is done, turn the breaker off to prevent potential problems.

    Once that (installing proper overcurrent protection for the smaller size conductor) has been done, then, yes, at any time in the future "it would be better to re-wire .. with appropriate size wire".

    I fully agree with you on that.

    Jerry Peck, Construction / Litigation Consultant
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  11. #11
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    Default Re: 14 AWG and 12 AWG wire splicing

    Thanks Jerry


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    Default Re: 14 AWG and 12 AWG wire splicing

    There is not any code support for requiring the 12 gauge wire change out. It is fine as is, just protect the circuit at 15 amps (because of the 14 gauge wire)


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Roland Miller View Post
    There is not any code support for requiring the 12 gauge wire change out. It is fine as is, just protect the circuit at 15 amps (because of the 14 gauge wire)
    Roland,

    You are only addressing the code aspect, what if the load aspect needs the 20 amp overcurrent protection for the load on the circuit?

    Yep, that would mean changing out the 14 AWG section and the newly installed 15 amp breaker and replacing with 12 AWG and a 20 amp breaker.

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    Default Re: 14 AWG and 12 AWG wire splicing

    All we know is the existing circuit was 14 gauge and 12 was spliced on to it. So a 15 amp breaker was adequate for the existing circuit. There is not enough information to even recommend a wire change out. Without additional load information we really can't say much more.


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    Default Re: 14 AWG and 12 AWG wire splicing

    To me, mismatched wire gauges spliced together are always a reason for concern and should be evaluated more closely. If you can trace the wires back to the panel interior and determine they are connected to the proper size breaker for the smallest gauge wire in the circuit, great. If you cannot, recommend a professional electrician for possible repairs. The interiors of some panel boxes are so cram packed with wires that it is hard to make heads or tails out of which breakers the wires go to.

    I'll sometimes unscrew a wire nut inside an open junction box if the wires look to be mismatched with the naked eye.


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Roland Miller View Post
    All we know is the existing circuit was 14 gauge and 12 was spliced on to it. So a 15 amp breaker was adequate for the existing circuit. There is not enough information to even recommend a wire change out. Without additional load information we really can't say much more.
    Rolland,

    The facts given (which are all we know about it) *did not include* "So a 15 amp breaker was adequate for the existing circuit.", it included "and are protected with 20 amp breakers".

    Thus, we can make no assumption about 15 amp breakers being sufficient.

    "There is not enough information to even recommend a wire change out.", that has been stated and agreed with several times, however, the statement is to install 15 amp protection, because of the 15 amp rated 14 AWG wire. Are you saying you disagree with that?

    Trying to pin you down on what it is you are saying, agreeing with, and not agreeing with.

    *I* am saying that it required, right here and right now, an overcurrent protection not greater than the smaller wire size, *15 amp breaker*.

    *Do you agree or disagree with that?*

    *I* am also saying that, *AFTER* the proper protection has been installed so the circuit is safe to leave energized, *THEN* is the time to determine if the 14 AWG needs to be replaced with 12 AWG and a 20 amp breaker re-installed after the wiring has all been replaced with 12 AWG minimum.

    *Do you agree or disagree with that?*

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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Michael Vasquez View Post
    the home owner has added recessed lights in the bedroom.

    Thanks
    This is really the only piece of necessary information in this entire thread.


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    Default Re: 14 AWG and 12 AWG wire splicing

    As long as the circuit does not cover an area exceeding 600 square feet --there could be an unlimited number of lights and receptacles added and still comply with the NEC. So the only change is the breaker to 15 amps.


  19. #19
    Richard Pultar's Avatar
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    Default Re: 14 AWG and 12 AWG wire splicing

    please explain ..3 watts per ft and all


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    Default Re: 14 AWG and 12 AWG wire splicing

    120 volts X 15 amps = 1800 volt amps

    1800 volt amps / 3 volt amps/ sq ft = 600 square feet

    So 1 - 15 amp circuit can supply all the general lighting load for each 600 square feet of floor space. There are no limits to the number of receptacles outlets and lighting outlets per circuit according to the NEC.


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    Smile Re: 14 AWG and 12 AWG wire splicing

    forgot to add-- in a dwelling unit


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Roland Miller View Post
    120 volts X 15 amps = 1800 volt amps

    1800 volt amps / 3 volt amps/ sq ft = 600 square feet

    So 1 - 15 amp circuit can supply all the general lighting load for each 600 square feet of floor space. There are no limits to the number of receptacles outlets and lighting outlets per circuit according to the NEC.
    Roland,

    While your math is correct as far as it goes, you have missed an important factor.

    You are explaining the minimum lighting load per square foot for dwelling units, then you are applying that to the maximum overcurrent protection on a 15 amp circuit without taking into consideration the maximum allowable load limitation on that 15 amp circuit.

    The load limitation is 80%, or 12 amps, thus a 15 amp circuit is only allowed to carry the load of 120 volts x 12 amps = 1440 volt/amps dividedby 3 volts/amps per square foot = 480 square feet.

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    Default Re: 14 AWG and 12 AWG wire splicing

    Jerry,

    I am just applying the NEC according to the following articles. What you stated has nothing to do with load calculations.

    210.3, 210.19, 210.23, 220.10 and chapter 9-examples

    Where do you fine the 80% thing in 210 or 220 of the NEC?


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Roland Miller View Post
    I am just applying the NEC according to the following articles.
    No, you are not applying the load calculations.

    You are making the load calculation based on "220.12 Lighting Load for Specified Occupancies." and "Table 220.12 General Lighting Loads by Occupancy".

    You cannot put in a circuit which will be at maximum overcurrent condition to cover that load, which is what you were doing.

    What you stated has nothing to do with load calculations.
    What I stated has to do with applying the load calculations after they have been made.

    To decide what size circuit to use, one must also address this:
    - 210.20 Overcurrent Protection.
    - - Branch-circuit conductors and equipment shall be protected by overcurrent protective devices that have a rating or setting that complies with 210.20(A) through (D).
    - - - (A) Continuous and Noncontinuous Loads. Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load.
    - - - - Exception: Where the assembly, including the overcurrent devices protecting the branch circuit(s), is listed for operation at 100 percent of its rating, the ampere rating of the overcurrent device shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load.

    Continuous Load. A load where the maximum current is expected to continue for 3 hours or more.

    Lighting is a continuous load.

    12 amps x 125% = 15 amps ... can also be calculated as ... 15 amps x 80% = 12 amps, i.e., the most you can put on that 15 amp circuit is 12 amps

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    Default Re: 14 AWG and 12 AWG wire splicing

    As we all know the NEC is not an after the fact standard. The lighting load in a dwelling unit is not a continuous load. Please refer to the definition in Article 100.

    "You cannot put in a circuit which will be at maximum overcurrent condition to cover that load, which is what you were doing." again this has nothing to do with this load calculation. Go through the example in chapter 9 so you understand the difference. The 600 square feet for a 15 amp circuit is correct according to the NEC.

    Again this is the calculation--not the installation.


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Jerry Peck View Post
    Continuous Load. A load where the maximum current is expected to continue for 3 hours or more.

    Lighting is a continuous load.
    Quote Originally Posted by Roland Miller View Post
    The lighting load in a dwelling unit is not a continuous load. Please refer to the definition in Article 100.
    Umm ... Rolland, did you even bother to read my post?

    *I DID* refer to the definitions in Article 100, in fact, I even posted it, see above.

    Jerry said:
    "You cannot put in a circuit which will be at maximum overcurrent condition to cover that load, which is what you were doing." again this has nothing to do with this load calculation. Go through the example in chapter 9 so you understand the difference. The 600 square feet for a 15 amp circuit is correct according to the NEC.

    Again this is the calculation--not the installation.
    Huh?

    YOU did the calculation. YOU ran the numbers FOR DETERMINING THE LOAD.

    *THE LOAD*

    "the load"

    Yeah, that's what you did.

    However, as soon as, ... yes, .. as soon as ... you state you can use ... yep, as soon as you state you can use ... you have now crossed over and gone beyond calculations, you are now addressing the sizing *BASED ON YOUR CALCULATIONS*, and, when you address the sizing, you need to leave the calculation section behind, take with your calculated load, and then go to other sections in the code which tell you how much load is allowed to be put on what, and that would be the section which tells you that the circuit overcurrent rating needs to be 125% of the load, and then you go to the section which tells you what size conductors are required for what size overcurrent protection you are using.

    In the example you have given, the load exceeds that which is permissible on a 15 amp circuit, meaning you would need to go to the next step up, a 20 amp circuit, which also means the wire size would need to go to the next size up, 12 AWG, or larger (there are other factors which could cause one to go larger, such as circuit length and voltage drop).

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    Default Re: 14 AWG and 12 AWG wire splicing

    I will have to say you analysis of how to apply the code is not according to the NEC for dwelling units.

    And you don't understand the installation seemingly.

    Again what you have stated has no basis in the calculation of loads in the NEC.
    If the circuit, as I have calculated it, was installed in a dwelling unit--it would comply with the NEC.

    Last edited by Roland Miller; 12-18-2008 at 12:13 PM. Reason: Technical errors

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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Roland Miller View Post
    I will have to say you analysis of how to apply the code is not according to the NEC for dwelling units. You don't seem to be able to apply the code without adding your opinion.
    Not adding my opinion, I am simply trying to point out to you, unsuccessfully it appears, that "calculations" is *only one* aspect of determining what is used for what.

    Again what you have stated has no basis in the calculation of loads in the NEC. You are mixing apples and oranges and your opinion.
    To the contrary, you have mixed the apples and oranges, I am trying to get you to separate the orange colored ones from the red colored ones.

    If the circuit, as I have calculated it, was installed in a dwelling unit--it would comply with the NEC.- end of story!!!
    End of story is right, you have not designed a circuit, you calculated the load for that circuit, then improperly tried to apply the load as the overcurrent rating and conductor size.

    Until you can see the orange color from the red color, you will never be able to separate the apples from the oranges.

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    Default Re: 14 AWG and 12 AWG wire splicing

    Just applying the NEC

    Last edited by Roland Miller; 12-18-2008 at 12:14 PM. Reason: error

  30. #30
    Ted Menelly's Avatar
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    Default Re: 14 AWG and 12 AWG wire splicing

    Now see. That only goes to show you that Jerry knows nothing of electric circuit. He thinks you can build circuits using apples and oranges. Geez


  31. #31
    Jeff Remas's Avatar
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    Default Re: 14 AWG and 12 AWG wire splicing

    Reading through the posts, I don't seem to be able to grasp what the disagreement is.

    The original post is a bit vague but I get the idea. (assume copper?)

    Sounds like the circuit was improper to begin with since it had a 20A OCPD with #14awg wire. This of course is wrong.

    The installer used 12awg to tie in some more devices. Great but still does not correct the problem.

    To fix what little we know, they need to imediately replace the 20A CB with a 15A due to the existing 14awg wire in the system. Then all might be OK depending on what the calculated load is for the circuit.

    If the caculated load is too high (depending on what it is) then that circuit will need to be changed appropriately.

    If the calculated load is OK for a 15a circuit then adding the 15A breaker to fix the initial, existing problem is all that is needed.

    What is the disagreement?


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    Default Re: 14 AWG and 12 AWG wire splicing

    I once stuck my finger in a light socket when I was 5 because my brothers dared me to. I had my misgivings about doing it but there was no mention in the 1974 NEC stating it was prohibited. Darn that code book (zzzt....zzzzzzzzzttttt).


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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Jeff Remas View Post
    Reading through the posts, I don't seem to be able to grasp what the disagreement is.

    The original post is a bit vague but I get the idea. (assume copper?)

    Sounds like the circuit was improper to begin with since it had a 20A OCPD with #14awg wire. This of course is wrong.

    The installer used 12awg to tie in some more devices. Great but still does not correct the problem.

    To fix what little we know, they need to imediately replace the 20A CB with a 15A due to the existing 14awg wire in the system. Then all might be OK depending on what the calculated load is for the circuit.

    If the caculated load is too high (depending on what it is) then that circuit will need to be changed appropriately.

    If the calculated load is OK for a 15a circuit then adding the 15A breaker to fix the initial, existing problem is all that is needed.

    What is the disagreement?
    Jeff, Jeff, Jeff..... There doesn't have to be a disagreement for people to argue for pages and pages on this board. Often times just a punctuation mark is enough. Especially, when it's the middle of winter in the middle of a real estate crisis.... we're all like a bunch of caged animals.


  34. #34
    Richard Pultar's Avatar
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    Default Re: 14 AWG and 12 AWG wire splicing

    I like to go by the rating of the highhats to determine the load.. because they are fixed in place. Whether the lamps are 15 or 100 watts is regardless.

    I like to add a note to the panel if anyone cares to read what the reason the 15 Amp breaker is there for.
    last month had a 14ga branch circuit added from /to a old bathroom circuit of 12 ga .and
    failed it just because...for no code reason , like I said just because...
    After explaining that someone might put a 20 amp breaker on what appears to be a12 ga line, and then while having it explained to me that the install was code proper.
    The electricians helper was putting in a 20 amp breaker. We put a note on the panel....


  35. #35
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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Jeff Remas View Post
    Reading through the posts, I don't seem to be able to grasp what the disagreement is.

    What is the disagreement?

    Jeff,

    Did you read Roland's posts #18 and #20?

    Roland is saying that you can use a 15 amp circuit to run 15 amps of load.

    I am saying that if you have 15 amps of load, you need a 20 amp circuit, that you are not allowed to run the circuit and the overcurrent protection at their full rating. See my posts #22 and #24.

    Hopefully those posts will explain the disagreement.

    Jerry Peck, Construction / Litigation Consultant
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  36. #36
    Jeff Remas's Avatar
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    Default Re: 14 AWG and 12 AWG wire splicing

    Quote Originally Posted by Jerry Peck View Post
    Roland is saying that you can use a 15 amp circuit to run 15 amps of load.
    Not if it is considered a continuous load.

    When I read post #20 he appeared to be trying to say that a 15A circuit can handle the lighting and receptacles for a 600sq ft. area which is what the calculation is for residential dwellings says when determining the number of circuits.


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