Pole mounted arrays - Inter array conduit routing

HuckMeat
HuckMeat Registered Users Posts: 24 ✭
in PV Installers Forum - NEC, Wiring, Installation #1
I'm getting ready to mount three pole mounted arrays, and fall under the 2008 NEC. Each array is mounted on an 8" SCH40 pipe.

1) How do I ground the pipe
2) Do I need to do a UFR at each array? There is a mess of rebar in the engineered foundations
3) For conduits between the arrays, is EMT OK for underground use? Rigid steel conduit? Or Sch80 PVC? Can both be routed through the concrete before I pour, and if so, do I need expansion joints (which would seem odd since the pole is in the same concrete). I figure I need an expansion joint at the house, but figured the horizontal exit from the pole mount foundation would allow vertical movement...
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  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #2
    Re: Pole mounted arrays - Inter array conduit routing

    You will want to use pvc conduit between arrays and I usually run it in the concrete.
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #3
    Re: Pole mounted arrays - Inter array conduit routing
    HuckMeat wrote: »
    I'm getting ready to mount three pole mounted arrays, and fall under the 2008 NEC. Each array is mounted on an 8" SCH40 pipe.

    1) How do I ground the pipe
    2) Do I need to do a UFR at each array? There is a mess of rebar in the engineered foundations
    3) For conduits between the arrays, is EMT OK for underground use? Rigid steel conduit? Or Sch80 PVC? Can both be routed through the concrete before I pour, and if so, do I need expansion joints (which would seem odd since the pole is in the same concrete). I figure I need an expansion joint at the house, but figured the horizontal exit from the pole mount foundation would allow vertical movement...

    1) I would place/drive a ground rod at each pole, and tie them together into a single common grounding system.

    2) You can. If you do go with UFER, then yes, do one at each array.

    3) EMT is NOT okay for underground - use rigid or PVC. I would go with PVC. Yes, you can run them underground before you pour. You don't need expansion joints to run the conduit out of one slab, through dirt and then into another slab. You do need them if the slabs are side-by-side.
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