can 2 Bucket Transformers share a neutral? House to house backup generator circuit.

[mivey]

What OP proposes does work. Might create some problems during abnormal conditions and some have mentioned codes being violated.

Unless you do switch the neutral with transfer switch you are going to have parallel path involving the EGC that was run with generator suppy circuit and the service neutrals/utility MGN. But if you don't run a neutral there is none to switch either.

I am in agreement with others in that one might be as well off to just buy another generator. Materials spent to go 600 feet will get you most of another generator or maybe even all of a cheap one from Harbor Freight.

The OP was going to run a neutral, just no ground.

 

[kwired]

The OP was going to run a neutral, just no ground.

Still has mostly the same thing if he doesn't switch neutral with transfer equipment.

 

[ptonsparky]

1" sch 40 cost .45*600=$270
Trenching $600
___________________________
$870
Plus wire
Plus donated time

 

[mbrooke]

Given that an auto tranformer is common for something like 14.4 to 7.2 kV, at what range would you think an isolation unit would be more common? I would expect something like 35 to 4 kV would be an iso but would have to read up on the pros and cons as the voltage spread changes. I usually hear the zero sequence blocking stuff and that can be a factor if you have accumulated a bunch of Z0 but I wonder what else makes the laundry list?

I've always heard that when its more that 3x, the tendency is an iso.

I have not seen a 115 to 35 kV auto until your pic.

They are out there. I know Vermont has tons of them (like 99% of the time) when stepping 115kv down to 34.5 or 46kv, both subtranmission voltages latter stepped down to 12.47kv.

I guess it would make sense- 46 x 3 = 138kv. 34.5 x 3= 103. So I guess there would still be some savings.

 

[kwired]

1" sch 40 cost .45*600=$270
Trenching $600
___________________________
$870
Plus wire
Plus donated time

Also don't forget the person benefiting from this doesn't need to buy gas for a generator.

If my neighbor and they can't afford this I'd probably ask them to stay at my house when there is prolonged power outage before installing a feed to their house, especially at 600 feet away.

 

[JFletcher]

Since last week, next Wednesday has come and gone... How did your installation go?

 

[mivey]

And with a dedicated equipment ground between house #2 and the generator aren't we putting most of the fault current on that low impedance path?

Felt froggy so I ran a model and a significant amount of current runs across the POCO neutral down the main line and back to the house with the generator.

The difference is with a generator at each house, parallel currents pretty much stay local to the service. When you join the houses with one generator and feed, the POCO line between the houses becomes part of the main current loop. It should not be there and is not safe.