Grounding sub-panel

Thanks, Stan

Depending on local code & if this is 2 seperate buildings and no shared plumbing & if considered agricultural, they allow a 3 wire, no ground wire between, service. Maybe. It's something to look into local code if the price diff is a lot. With this, both panels would be ptreated like a main panel, both with ground rods, both with bonded neutral/ground buss. This would depend alot on your local inspector, the ag exception is in the rules, but somewhat gray area.

--->Paul

FURTHERMORE at that sub panel and UNLIKE at the main service entrance panel THE NEUTRAL BUSS AND THE EQUIPMENT GROUND BUSSES DO NOTTTTT TTTTT BOND TOGETHER. THEY REMAIN SEPERATE N ISOLATED FROM EACH OTHER. His incoming Neutral (White) obviously goes to his sub panels Neutral buss while his incoming Equipment Ground (bare/green) goes to the sub panels Equipment Ground Buss. The sheet metal of the panel would bond to the equipment ground buss not the Neutral of course

The wire sizes depends on the amps and length of run. We did NOT use any additional grounding electrodes (driven rods or water pipes or building steel etc) at the sub panels in the same buildings.

Headed to Moline Illinois to speak at the John Deere Gathering of the Green Conference, see yall soon

John T

Thank you both for the information. I'm going over to take a look at my friend's setup in a week or so. He knows so little about it that it's difficult to find a common language to ask questions about what he has. The 70 amp sub-panel has been in place and in use for 5 years. What my friend can tell me about it for sure is that the distance involved is 250', and there is no grounding rod at the sub-panel location. He says that the cable between the two panels is #2 aluminum. He may mean 2/0, but I won't know until I see it.

My guess is that my friend got reasonably good advice about the installation 5 years ago, and now he doesn't remember enough about what was done then to even talk about it in terms that tell me much. I think he will do what needs to be done or spend what needs to be spent to correct any problems that could endanger others, and that's about it.

Thanks, Stan

This can be tough over the net not being there to observe the actual conditions, best consult a local engineer or electrician is my best advice, electricity can killlll lll if the installations isnt correct.....

John T Long retired electrical engineer