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diy solar

Grounding thoughts for barn.

cdsolar

caduceus
Joined
Dec 16, 2022
Messages
272
Location
Utah, USA
Scenario:

1. Metal pole barn, walls are steel.
2. Ground mount PV array (I was previously going to do a side-of-building mount -- too complicated)
3. 60-70ft cable run from PV to panel with MPPT SCC and other equipment (PV disconnect, battery, et al) through rafters of barn.
4. I will ground the array itself and its frame to a grounding rod buried next to the barn.

The question is, how to I ground the stuff at the panel? I see three options:

1. Run a cable, probably in same conduit as is the cable coming in from the array, back to the grounding rod and use this cable as ground for the electric panel with a busbar, Thus grounding cable will be 60-70ft, and through rafters.
2. Ground with a clamp the electrical panel to the steel wall of the barn, and link the grounding rod near the PV panels to the wall of the barn at its location on the other side of the barn. The wall is contiguous all the way around the building, although not all at the same height (up and over a garage door).
3. Install a separate grounding rod next to the panel with the MPPT et al. Ground the electrical system to this rod. Bond both rods to each other by linking both rods to the steel frame of the barn.

#2/#3 saves a cable run *If* my thought process is correct. Of course, getting it through inspection would be the final objective.
 
Contact your local inspector and ask them what they want to see. They're usually really good if you're asking a code question. Whatever you do DON'T JUST GUESS!! There'll be a 110% chance you guess wrong.
I'm already in touch with my inspector, Posting here first I have found often gives me fodder to ask the question more intelligently, or give options. Don't worry, I will not guess, thanks.
 
Two ground rods 6ft apart close to the main service panel. Connected to its ground bar.
Properly sized equipment grounding conductors ran from main service panel to all metal raceways, enclosues, frames and supports. Should travel with the circuit conductors.
 
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