AC disconnect wire burned out

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  • cantgetaname
    Junior Member
    • Aug 2019
    • 5

    AC disconnect wire burned out

    I have an Square D DU222RB , 60A, 240V x 2p Non Fusible AC disconnect. My system went down yesterday and this is what i saw, one of the wires had melted. My system is 12,726 watts and 53.025 amps. My system consist of 41 panels and 4 strings that each feed into a 20amp breaker. Due to the amperage i used 6 awg copper wire is this to low? My diagram passed code and its been installed for a year before this happened but i was reading that maybe that fact that i have 4 branch circuits of 20amps feeding into the disconnect i need to have a larger wire size? do i also need a larger amperage disconnect?

    Screenshot 2024-06-10 114945.jpg
  • Mike 134
    Solar Fanatic
    • Jan 2022
    • 390

    It was a bad connection. See how the insulation stopped melting about 6" back? Had it been a wire size problem the entire length would have been melted. And the load side of the black wire also would have been melted.
    You'll need a new disconnect unless your skilled in electrical repair.
    Last edited by Mike 134; 06-10-2024, 04:41 PM.