fuse size for #10 wire

bobdogbobdog Posts: 191Solar Expert ✭✭✭✭✭
Is it 30 amp or 40 amp max? And how about #6 wire? Thanks.


  • BB.BB. Posts: 25,442Super Moderators admin
    Re: fuse size for #10 wire

    Depends... Are you going with NEC (National Electric Code)? Is the wire type Listed in the NEC? Is it going in Conduit? Conduit Fill Factor? Open Air?

    This chart lists maximum amperage (no insulation type listed) for chassis (open air?) type wiring.

    For example, typically NEC lists 14 AWG as 15 amp fuse. That chart lists at 32 amps maximum. For sending energy any distance, it seems to be very conservative (14 awg = 5.9 amps).

    This chart seems to list generic NEC type ratings (fill factor?).

    If you are going to do this a lot using "house wiring"--then you should get a copy of the current NEC. (no--I don't have a copy :blush:).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bobdogbobdog Posts: 191Solar Expert ✭✭✭✭✭
    Re: fuse size for #10 wire

    Thanks Bill., The NEC chart is what I was looking for. I book marked it. It is for the battery bank back to the panel. I am using #10 right now and would like to fuse it at the post via the Blue Sea terminal post fuses that Tony talks about. I ordered a 40 amp and now will ask them to change to a 30 amp fuse.
  • mike95490mike95490 Posts: 6,563Solar Expert ✭✭✭✭
    Re: fuse size for #10 wire

    I've always used the romex calc,
    10ga = 30A
    12ga = 20A
    14ga = 15A
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  • RCinFLARCinFLA Posts: 1,280Solar Expert ✭✭
    Re: fuse size for #10 wire

    The NEC charts are based on heating per foot which does not assure a satisfactory voltage drop for any given total run length.

    Wire types that have multiple layers of insulation like SOOW cord have a lower max current rating for their wire size because of inability to dissipate heat. The heat dissipation also derates for number of current carrying conductors in a conduit/cord bundle which generates more heat in a given confined area.

    Original reasoning was elevated heating will progressively degrade wire insulation, making it brittle. Modern wire insulation is much better at resisting enbrittlement.
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