# Distribution on a large ranch - grounding...



## GarrikActual (May 2, 2021)

My ranch is off grid, power is provided by a solar system with generator backup. The solar inverter, batteries, charge controller and the backup generator are co-located in a small building. I am going to think of this as my "service entrance." I have 240v single phase coming out of the inverter - I think of it as a 240v single phase service.

I want to run power from my service entrance along about 2,000' of road. I will install the cable carrying the power underground. Most likely, I will use 4/0, 4/0, 2/0 URD, but that isn't the question here. I know how to size the service cable based on voltage loss. Along the road, every few hundred feet, I want to place a 110v outlet in case I need to run a pump or a hand drill or something. Max load 15 amps at each one.

In three places, I need to feed what I am thinking of as a sub-panel. One is a barn, one is a trailer, the third is an garage. In each case, I intend to install a small sub-panel. 50 amps or less each.

My question is how to handle grounding.

My understanding of the NEC is that I need to run an EGC along with my URD "service cable". I understand how to size the EGC based on the total load.

My understanding is that I must install a grounding electrode at each sub-panel, and that I must tie the electrode to the EGC and NOT bond the grounding system to the neutral.

First question, is my reading of the NEC correct with respect to grounding the outbuilding sub-panels, even given that one of them will be close to 1,500' from the "service entrance"?

Second question, how to I handle grounding at the stand-alone outlets? My read is that I do not install a grounding electrode at each outlet, and I do not bond the EGC to neutral at each outlet. But I do bond the metal components of the outlets to the EGC. Does that sound correct?

Thanks much!


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## magicone2571 (Apr 29, 2021)

I can't answer for the grounding but you're going to need a lot more than 4/0 to get 150amp at 240 volt 2000ft. Simple calculation shows 3x 1000mcm Al per leg. You might want to look into some transformer setup.


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## paulengr (Oct 8, 2017)

Those receptacles along the way are a problem. You will end up with separate feeds for those. Also you are attempting to do some strange things here. Service entrance it is not. Service entrance connects to a main distribution panel which is where your 240 grounding starts from, the main bonding jumper. Need to start that at your "source" even if the main distribution panel is rather simple. And VD is not just theory...its a HUGE problem. RV parks for instance often run into this. Plan on say a step up transformer to say 600 V then step down at each of your 3 load centers with their own main panels fed from the step down transformers. Stepping up to 600 V decreases your currents by 250%.


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## magicone2571 (Apr 29, 2021)

Well this would get you down to about an amp on the primary. That would work on your 4/0. But 









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## Kevin (Feb 14, 2017)

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