OCPD on Combiner Output

czarsczars Registered Users Posts: 16
For a grid tied system with battery backup, is over-current protection required immediately following the combiner? I can't get DC backfed from the inverter because it can't do that. However, I don't know about the batteries back feeding through the charge controller. I read NEC 2008 690.9 and I can't get a clear answer to my question. Can anyone provide a clear answer?

Comments

  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: OCPD on Combiner Output
    czars wrote: »
    For a grid tied system with battery backup, is over-current protection required immediately following the combiner? I can't get DC backfed from the inverter because it can't do that. However, I don't know about the batteries back feeding through the charge controller. I read NEC 2008 690.9 and I can't get a clear answer to my question. Can anyone provide a clear answer?
    Personally, I believe in OCPD on every node even if technically not necessary. The output of a combiner is a node separate from the string inputs, so if the controller is not protected at the input I would use a fused DC disconnect between the combiner and the controller.
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