Shop to House or Generator back feed

[WutCudGoWrong?]

Utility only provides L1, L2 and G right, not neutral? That's why I was suggesting that he supply the two hots and ground to each panel, then create the bond/earth at each panel, like the utility did.

I like your plan.

Most US residential, utility provides L1, L2, and neutral. They do not provide what most of us would call a “ground”

The rest of this is probably TMI:

The neutral from the utility is actually center tapped in between the L1 and L2

The neutral is “bonded“ or maybe better to say “referenced“ to ground with a ground rod out in the wider utility system, intermittently at different poles. if they didn’t do this, the neutral could actually drift and be like off-center, so to speak, when compared between different houses on different blocks. I mean you might see 110 between L1 and neutral, and 130 between L2 and neutral. Which would be bad for some 120v electronics.

The other important reason they do this, is because all electricity into a house needs to exit the house and go back to the generating station somehow. So when something goes wrong and you have current flowing into your ground wire, It goes to your panel, out to the ground rod, into the Earth, through the Earth, to the ground rod at the utility system, and back into the neutral in the utility system. Typically the faster path is from your ground rod back to the utility ground rod but hypothetically go from your ground rod into your neighbors, ground rod and back through their neutral. Because of math and physics I don’t think this happens in any sort of statistically significant way. If they didn’t do this, you could have an imbalance eventually back at the station. In theory.

So you’re doing the same thing at your panel when you bond the neutral, but only your main panel, referencing the neutral point so L1 and L2 are balanced compared to ground.

The reason you don’t bond at multiple panels is because now you have two parallel wires going from panel to panel on the same “leg” the neutral leg, and often the neutral wire is bigger than the ground wire, and so math and physics weird stuff about how many amps in each wire, overheating, melting fires, also sensitive electronics currents going places they shouldn’t on terminals they shouldn’t see current blah blah blah. You can do parallel wires but it’s kind of a thing and so they only do it with really big stuff where two fat wires are cheaper than one ginormous fat wire is what’s required.

That being said, you do want a ground rod at a sub panel for an outbuilding, and you can even run a ground wire from the house to the sub panel. You just don’t want to bond it at the panel. In the extreme, there is no problem with running a separate ground rod out from every receptacle in your house

Now the OP situation is a little different, think of it like he owns two houses next to each other. (The shop is on its own utility drop). To have one generator serve two houses, well, you are building a second “ utility“ system.

which is where it gets complicated, because you would “have to” 😈 simultaneously disconnect both “houses“ from the main utility system at the same time before energizing the utility system.

 

[GLTHFJ60]

Most US residential, utility provides L1, L2, and neutral. They do not provide what most of us would call a “ground”

The rest of this is probably TMI:

The neutral from the utility is actually center tapped in between the L1 and L2

The neutral is “bonded“ or maybe better to say “referenced“ to ground with a ground rod out in the wider utility system, intermittently at different poles. if they didn’t do this, the neutral could actually drift and be like off-center, so to speak, when compared between different houses on different blocks. I mean you might see 110 between L1 and neutral, and 130 between L2 and neutral. Which would be bad for some 120v electronics.

The other important reason they do this, is because all electricity into a house needs to exit the house and go back to the generating station somehow. So when something goes wrong and you have current flowing into your ground wire, It goes to your panel, out to the ground rod, into the Earth, through the Earth, to the ground rod at the utility system, and back into the neutral in the utility system. Typically the faster path is from your ground rod back to the utility ground rod but hypothetically go from your ground rod into your neighbors, ground rod and back through their neutral. Because of math and physics I don’t think this happens in any sort of statistically significant way. If they didn’t do this, you could have an imbalance eventually back at the station. In theory.

So you’re doing the same thing at your panel when you bond the neutral, but only your main panel, referencing the neutral point so L1 and L2 are balanced compared to ground.

The reason you don’t bond at multiple panels is because now you have two parallel wires going from panel to panel on the same “leg” the neutral leg, and often the neutral wire is bigger than the ground wire, and so math and physics weird stuff about how many amps in each wire, overheating, melting fires, also sensitive electronics currents going places they shouldn’t on terminals they shouldn’t see current blah blah blah. You can do parallel wires but it’s kind of a thing and so they only do it with really big stuff where two fat wires are cheaper than one ginormous fat wire is what’s required.

That being said, you do want a ground rod at a sub panel for an outbuilding, and you can even run a ground wire from the house to the sub panel. You just don’t want to bond it at the panel. In the extreme, there is no problem with running a separate ground rod out from every receptacle in your house

Now the OP situation is a little different, think of it like he owns two houses next to each other. (The shop is on its own utility drop). To have one generator serve two houses, well, you are building a second “ utility“ system.

which is where it gets complicated, because you would “have to” 😈 simultaneously disconnect both “houses“ from the main utility system at the same time before energizing the utility system.

That's an awesome explanation, thank you! TIL