Dishwasher Power Wire Burned Out

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  • JoeyGee
    Veteran Member
    • Nov 2005
    • 1509
    • Sylvania, OH, USA.
    • BT3100-1

    Dishwasher Power Wire Burned Out

    Our dishwasher has been acting up lately--running really loud and not cleaning dishes. I bought a new one and went to replace it and found the black wire feeding into the washer burned out. The plate in front was black with soot. I had no idea this had happened--no smell or smoke--until I pulled off the front panel.

    Any ideas on whether this would be on the supply side or if it would be on the washer? Basically, I want to know if if it's safe to just replace the washer or if I need to investigate an electrical issue. I assume it would be an electrical problem, but I am hoping just replacing the washer would fix the problem .

    Would a blown or overheated motor cause this type of issue?
    Attached Files
    Joe
  • Black wallnut
    cycling to health
    • Jan 2003
    • 4715
    • Ellensburg, Wa, USA.
    • BT3k 1999

    #2
    Did the breaker ever pop?
    Donate to my Tour de Cure


    marK in WA and Ryobi Fanatic Association State President ©

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    Comment

    • JoeyGee
      Veteran Member
      • Nov 2005
      • 1509
      • Sylvania, OH, USA.
      • BT3100-1

      #3
      No, no breaker popped, which has me worried.

      I took it apart and there is no charring on the supply side wire, just the dishwasher side wire.
      Joe

      Comment

      • Daryl
        Senior Member
        • May 2004
        • 831
        • .

        #4
        Looks like either a bad connection, or the wire was rubbing the cover plate. I would say the problem is right there and doesn't involve the power feed or the rest of the machine.
        Sometimes the old man passed out and left the am radio on so I got to hear the oldie songs and current event kind of things

        Comment

        • LCHIEN
          Internet Fact Checker
          • Dec 2002
          • 20920
          • Katy, TX, USA.
          • BT3000 vintage 1999

          #5
          It looks like the twist connector (wire-nut) is the thing that took all the heat - localized to the connector.

          That means that the two wires under the wire-nut connector was not making a solid connection.
          That exonerates the house wiring etc.

          Looking at it analytically, say your dishwasher pulls 5 Amps. Say your wires were not twisted tightly and had 1 ohm resistance which is not a lot but in this case is a problem as connections typically have much less than 0.1 ohm.

          In the context of your dishwaher 1 ohm extra series resistance is not a lot (causes 5V loss at 5 Amps and your washer would probably still work reasonably at 110V.)

          If there were 5A drawn by the dishwasher, then the heat in this connector would be I^2 x R which is 25 Watts. 25 watts dissipated in the space of the metal cup where the wires join would be a lot - enough to cause melting of the insulator cap and charring of the cap, wire insulators and anything touching it.

          Solution:
          Make sure that the wires are tightly twisted and the twist cap is on tight.
          It is very important that the right sized twist wire nut is used. They are color coded and the package says exactly what combination of wires is permitted. Too large or too small will cause insufficient compression to be placed on the wires and a high ohmic contact will result.

          You are lucky that nothing flammable touched the wire nut connector or it could have been ignited.
          Last edited by LCHIEN; 11-17-2014, 08:02 PM.
          Loring in Katy, TX USA
          If your only tool is a hammer, you tend to treat all problems as if they were nails.
          BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

          Comment

          • tfischer
            Veteran Member
            • Jul 2003
            • 2343
            • Plymouth (Minneapolis), MN, USA.
            • BT3100

            #6
            Yeah a bad connection (loose screw or wire nut) can do this.

            Comment

            • JoeyGee
              Veteran Member
              • Nov 2005
              • 1509
              • Sylvania, OH, USA.
              • BT3100-1

              #7
              Thanks for the responses.

              Quick update. I replaced the old dish washer and wired the new one, making sure connections are good with the proper wire nuts. So far, so good.
              Joe

              Comment

              • Stytooner
                Roll Tide RIP Lee
                • Dec 2002
                • 4301
                • Robertsdale, AL, USA.
                • BT3100

                #8
                I've seen this happen a few times. Every time I have seen it was when stranded wire was connected to solid wire. I know it is done often, but even more crucial that the correct sized wire nut is used. Also critical to twist them to start with using pliers and make sure that the stranded wire is longer than the solid one. That way once it is tightened in the nut, it can't pull out.

                Hard screw terminals are much preferred for equipment installation. That is the proper way to design equipment.
                Lee

                Comment

                • All Thumbs
                  Established Member
                  • Oct 2009
                  • 322
                  • Penn Hills, PA
                  • BT3K/Saw-Stop

                  #9
                  I agree w/ Stytooner, and am curious to know whether there are any stranded conductors involved. Because if there are my take is a conventional wire nut really isn't optimum and I'd rather use a Lever Nut. I've just had stranded conductors fall right out of wire nuts too many times to trust them any more.

                  Comment

                  • JoeyGee
                    Veteran Member
                    • Nov 2005
                    • 1509
                    • Sylvania, OH, USA.
                    • BT3100-1

                    #10
                    Yes, that is exactly the case. The dishwasher (old and new) both have stranded wires and the house wiring is solid.

                    Interesting, I had never heard of lever nuts. Looks like a clean and easy way to join wires.
                    Joe

                    Comment

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