Grounding/bonding: I know like an oil thread on a motorhead board

[toothy]

Hello,

I am off grid and have a gen/inverter shed feeding a house and shop both about 200 ft from the inv/gen shed both wired for 120/240. I have 3 wires running from the gen /inv shed to both panels a H-H-N. I have my earth ground at the gen/inv shed bonded to my neutral. I have the ground busbar in the shop, house and inv/gen shed each connected to earth ground, see my art work.

Am I supposed to have a 4th ground conductor running with the H-H-N back to the gen shed where it is currently bonded N to G?

If yes, am I supposed to disconnect the earth ground from the ground busbar at the house and shop panels and rely on the earth ground at the gen/inv shed?

If we could lets keep it simple or you'll make my head hurt, not too much code section or wire size stuff! Broad strokes.

Thanks
Wade

 

[Hedges]

Yes, from wherever you decided to have the single-point bond of neutral to ground, you should run a ground conductor to other loads.

Exception would be if you went through an isolation transformer, or connected the two hots to an auto-transformer and generated a new neutral (isolated from the generator shed). Then you could establish a new ground and neutral/ground bond.

You don't want to have neutral currents traveling through what is also your ground wire.

 

[toothy]

Thanks Hedges,

So, I should disconnect the earth ground and or Ufer ground at the house and shop panels when I run the 4th wire and connect that 4th one to the ground busbars?

 

[Hedges]

I wouldn't say disconnect grounds, I think multiple buildings connected to a single utility drop are each supposed to have ground rods.
Just disconnect neutral from them. Connect the 4th (ground) wire to a ground busbar in sub panel, and connect rod/Ufer/conduit/pipes together with the ground. Don't want anything metal to possibly be at a different potential from chassis ground of equipment plugged in.

Code Q&A: Grounding and Bonding for Remote Building

Your most pressing National Electrical Code (NEC) questions answered

www.ecmweb.com

 

[toothy]

That's where I was having problems. To my way of thinking, I know I should avoid that, the shortest path to ground is the best. I can understand having all grounds hooked together with wire and only one neutral bonding site.

Thanks Again
Merry Christmas

 

[Zil]

Your generator is the power supply like the grid would be. The house and the shop should have the green wire back to the power shed and connect to mother-Earth Ground at only one point. Where the g-n bond is made. I don't think it would hurt to have the earth ground also made at the house and shop as long as the G-N bond are only at the one point in the power shed.