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        Melted Neutral / Anything inherently wrong with this circuit? Sign In/Join 
        posted
        Hi, I have a circuit that goes:
        - 20a breaker
        - to about 15ft 12/2
        - to junction box
        - to about 30 ft of 10/2
        - to a 20a/125v single outlet recepticle
        - to a 11 amp window/wall unit A/C.

        Nothing else is on the circuit. The recepticle stopped working due to melted neutal wire near the outlet. Do I just cut back the wire and reattach the outlet, or is there something inherently wrong with this circuit?

        Thanks for any advice...
         
        Posts: 3 | Registered: Oct 27, 2013Reply With QuoteReport This Post
        posted Hide Post
        there is no way you melt a 10 gauge neutral with 11 amps on the circuit. there is another explanation and it's going to take a little research.

        little reason for a junction or a 10 gauge wire on that short a circuit. who knows why that was done.

        best advice is to get a pro to scope that out. preliminary step I'd take is check for voltage between ground and neutral. if there is any, something is indeed terribly wrong, and most likely it is another miswired line on the same phase of power that is somehow using that return.

        what I'd do, frankly, is pull a whole new dedicated 12 gauge feed directly to that circuit. a clever move would be to trace that existing line back to the panel, and lift both the neutral and ground and see if anything else dies. besides yourself, so I'd definitely switch off the mains first.

        if that makes you nervous, call the pro. always the safest choice. power is life-safety stuff, although the phrase is reserved in Code for hospital stuff.


        sig: if this is a new economy, how come they still want my old-fashioned money?
         
        Posts: 5820 | Location: North Burbs, MN | Registered: Mar 14, 2007Reply With QuoteReport This Post
        posted Hide Post
        Thanks for the reply. I did trace it, I detailed the entire circuit above in my first post. The A/C single outlet is the only receptacle/device on the circuit. Nothing else ties in.

        I think the neutral was loose on the outlet, causing it to overheat. Which I think explains what happened.

        What I'm confused about now is, the wire nut connecting the two neutrals in the attic junction box, was also melted?? So maybe that was loose too?

        Odd and scary that it burned at both ends like that.

        This message has been edited. Last edited by: cjsks,
         
        Posts: 3 | Registered: Oct 27, 2013Reply With QuoteReport This Post
        Picture of CommonwealthSparky
        posted Hide Post
        Pulling a new dedicated circuit will allow you to sleep peacefully at night. May save your house and life as well. Any connection in the existing circuit that is made up poorly can and will fail, correct you are. One very hard connection to make up is with two different sized copper wires. Could be your problem, but it does not mean a lot now. Someone else may have cobbled together those two different sized copper as a money saver, again just a hunch.
        Since your run is about 45' or so the price of Romex is not a deal breaker either. According to the NEC the circuit should be protected with an Arc Fault Circuit Breaker as well. {As you are upgrading a circuit, it must be up to the current NEC standards}. Just thought I would include that bit of information. But not sure of your abilities doing electrical work. Good luck with your work.

        This message has been edited. Last edited by: CommonwealthSparky,


        Popeye only reached for the Spinach can as a last resort...
         
        Posts: 1535 | Location: Central Pennsylvania | Registered: Jun 02, 2010Reply With QuoteReport This Post
        Picture of CommonwealthSparky
        posted Hide Post
        [QUOTE]Originally posted by swschrad:
        there is no way you melt a 10 gauge neutral with 11 amps on the circuit. there is another explanation and it's going to take a little research.

        little reason for a junction or a 10 gauge wire on that short a circuit. who knows why that was done.

        best advice is to get a pro to scope that out. preliminary step I'd take is check for voltage between ground and neutral. if there is any, something is indeed terribly wrong, and most likely it is another miswired line on the same phase of power that is somehow using that return.

        what I'd do, frankly, is pull a whole new dedicated 12 gauge feed directly to that circuit. a clever move would be to trace that existing line back to the panel, and lift both the neutral and ground and see if anything else dies. besides yourself, so I'd definitely switch off the mains first.

        if that makes you nervous, call the pro. always the safest choice. power is life-safety stuff, although the phrase is reserved in Code for hospital stuff.[/QUOTE
        -----------------------------------------------------

        Actually a poorly made up connection will do exactly that, arc and melt that connection.
        A shared neutral is rare unless the Romex has two hot legs present, as in 12/3 cable.
        Not sure what your point is with the hospital code stuff either.

        This message has been edited. Last edited by: CommonwealthSparky,


        Popeye only reached for the Spinach can as a last resort...
         
        Posts: 1535 | Location: Central Pennsylvania | Registered: Jun 02, 2010Reply With QuoteReport This Post
        Picture of Jaybee
        posted Hide Post
        quote:
        Originally posted by CommonwealthSparky:
        Any connection in the existing circuit that is made up poorly can and will fail, correct you are. .


        I KNEW it! CommonwealthSparky is Yoda!


        Jaybee
         
        Posts: 10425 | Location: Knoxville, Tennessee | Registered: Sep 27, 2003Reply With QuoteReport This Post
        posted Hide Post
        Thanks for all the feedback, I think the neutral connection was loose in both the junction box and on the outlet, which is most likely why it melted at both points.

        I'm guessing they switched from 12 to 10 gauge to combat voltage drop, even if the distance doesn't really justify it.

        I guess you have to be careful when working 10/2 into connections due to larger diameter being a little more difficult to work with.

        I am going to install an AFCI as a added precaution.

        Thanks!
         
        Posts: 3 | Registered: Oct 27, 2013Reply With QuoteReport This Post
        Picture of CommonwealthSparky
        posted Hide Post
        quote:
        Originally posted by cjsks:
        Thanks for all the feedback, I think the neutral connection was loose in both the junction box and on the outlet, which is most likely why it melted at both points.

        I'm guessing they switched from 12 to 10 gauge to combat voltage drop, even if the distance doesn't really justify it.

        I guess you have to be careful when working 10/2 into connections due to larger diameter being a little more difficult to work with.

        I am going to install an AFCI as a added precaution.

        Thanks!

        _____________________________________________________
        Just an addendum here: Adding a larger AWG piece of Romex 10/2 midway in a circuit will not help solve voltage drop issues if present. Mainly because of the 12/2 that starts the circuit. {And a 45' run of Romex will have nominal voltage drop present as you stated}. Thought I would pass that on just to clarify your wiring set up. But it does sound like it would help, but no. Wink Methinks what was installed was what was lying around that day, but who knows for sure. Back in the day figuring out voltage drop was taking pen to pad and running the numbers. The world we live in today smart phones whip out an answer as fast as you can type.
        If the original handyman had installed an AFCI the problem may have been caught by that type of breaker.
        Make sure that the new breaker is the combo type of AFCI breaker as that type will detect two types of arcing. Combo AFCIs are code now but I never saw an inspector question the exact type installed. Regular AFCIs are still lying around on store shelf's so beware. Might have something to do with the price of these breakers. Say in the ballpark of about 45 US greenbacks a pop. Might be the reason that many homeowners try and wiggle around the purchase of these devices when called for.
        Good luck with your project !!!

        This message has been edited. Last edited by: CommonwealthSparky,


        Popeye only reached for the Spinach can as a last resort...
         
        Posts: 1535 | Location: Central Pennsylvania | Registered: Jun 02, 2010Reply With QuoteReport This Post
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