Lost wire Bonding terminal

Farmer
Farmer Registered Users Posts: 24 ✭
in Solar Beginners Corner #1
I have one last wire to connect the bonding wire coming back from the panels comes into my SMA disconnect and it does not show a spot for the wire it only has it on the AC side. In my 8000w inverter it has no place marked BT it does have two grounding spots one with a circle and one without. Where does that bonding wire go in the inverter?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #2
    Re: Lost wire Bonding terminal

    Is this a Grid Tie or Off Grid inverter?

    In thoery, there is only one frame/chassis ground for the inverter. From an AC/DC point of view, the wire just has to be heavy enough to carry enough current to trip a breaker or fuse (or Isc of the solar array). For an off grid inverter, it also needs to be heavy enough to carry a DC short circuit too (DC being ~4-10x the current vs the AC side of the inverter).

    For lightning Control--I am a big fan of bringing the frame grounds from the array down the outside of the building to ground rod/ground plate next to the foundation. And don't bring the lightning energy into the home.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Farmer
    Farmer Registered Users Posts: 24 ✭
    #3
    Re: Lost wire Bonding terminal

    Grid Tie and yes I did ground the chase directly to ground but the inspector only accepts rule 64-020 in the code book where the ground and the bonding conductor are seperated the diagram in the code book shows the panels,dc disconnect and the inverter bonded together. And a separate ground for the inverter on the DC side.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #4
    Re: Lost wire Bonding terminal

    Sometimes you have to do what the inspector says, and then "fix it" later.

    Without seeing your installation and comparing against the code.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • jaggedben
    jaggedben Solar Expert Posts: 230 ✭✭
    #5
    Re: Lost wire Bonding terminal

    The grounding terminals in the SMA disconnect are all directly attache to the same trace on the circuit board, so they are all functionally equivalent. The inspector can see this for himself if you ask him to look. Also follow the SMA manual and show the inspector that you've done so. If I recall correctly, you are supposed to connect the grounding electrode conductor to the one with the circle on it. The others can be used for any other bonding connections. In actuality, it doesn't matter which you use for which.

    Rule 60-420 is not a reference to an NEC section. You'll need to tell us what code you are subject to if you want some help with code interpretation.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #6
    Re: Lost wire Bonding terminal
    jaggedben wrote: »
    Rule 60-420 is not a reference to an NEC section. You'll need to tell us what code you are subject to if you want some help with code interpretation.

    It might be a reference to an illustration in the Handbook which is a companion piece to the NEC, and is NOT enforceable by itself.
    SMA SB 3000, old BP panels.
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