Question about .5A Breaker

vibeline
vibeline Registered Users Posts: 24 ✭✭
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Please explain to me what that 1/2Amp breaker is doing?
Thanks,

Comments

  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Question about .5A Breaker
    vibeline wrote: »
    Please explain to me what that 1/2Amp breaker is doing?
    Thanks,

    It is part of a ground fault protection device. It is ganged to a 63 amp breaker that disconnects the solar panel when the .5 amp breaker trips.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • vibeline
    vibeline Registered Users Posts: 24 ✭✭
    Re: Question about .5A Breaker
    vtmaps wrote: »
    It is part of a ground fault protection device. It is ganged to a 63 amp breaker that disconnects the solar panel when the .5 amp breaker trips.

    --vtMaps
    What would cause the .5A breaker to trip?
    Thanks for the reply,
    Cheers.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Question about .5A Breaker

    As vtMaps says--The 0.5 (or 1-5 amp) breaker is between Battery Return (typically negative lead) and Earth/Safety/Green Wire Ground.

    If there is a Hot to Safety Ground short, the 0.5 amp breaker trips which then opens the ganged 63 amp breaker too which is connected to the + to the solar array (or in newer Outback drawings, I understand the 63 amp breaker is between the charge controller and the battery bank).

    The intent was to reduce the chance of Arc Faults in the solar array (short circuits in PV circuits tend to produce steady arcs instead of "popping a breaker or a fuse). This was a first past NEC attempt at "solving" the Arc Fault problem in solar arrays.

    Personally, I think a fuse/breaker between DC Return and Safety Ground (+earth ground rod) is not a safe thing to do.

    There are some devices (such as newer Midnite Classic MPPT controllers) that have Arc Fault detection circuitry that can shut down the current flow if there is an Arc Fault detected--But this is not widely implemented at this time, nor a 100% fix either.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset