Electrical Wizards, Another Panel/subpanel question

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Ok, i understand the whole panel/subpanel setup. And isolating the neutral from the ground in the sub etc etc. Here's the question: We've recently purchased a house (next door) and it has the typical farm setup, (meter on the pole with a disconnect, and three wires to the house). The difference with this one is that there is a second panel that was added in about 1960, when they added on to the house, which i assumed at first was just a sub off the main panel. I just noticed today that the second panel is ALSO tied into the feeders just outside the house and so it in effect is a second main panel. Are there any issues with it being this way as long as each panel has it's own pair of proper ground rods? Should the two be bonded together either at the ground rods OR between the two panels?
thanks!
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Steve Barker
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I don't know the answer to your question. I'm not even sure I understand the question. But I know this. In my area, if you have a hookup like that running off of just one meter, you gonna pay. If I understand the hookup correctly, what is happening is that they were stealing power by getting an additional level of service at the reduced rate charged after a certain level of usage. People around here have actually gone to jail for that.
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The Post Quartermaster wrote:

What??????????? I have 2 main panels run off of one main with a meter on the pole with the transformer. One to the house and one to the garage. The power company told me that is the best way to do it so I don't have to have 2 meters.
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Tony wrote:

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ROANIN wrote:

They do it at farms all the time with all the different outbuildings. I don't know but maybe the first residential rate meter is on the house and commercial rates to all the outbuildings?
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wrote:

Is the garage a separate structure? That is the difference. I got the impression the OP was talking about two service drops to one building.
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On 7/8/2010 7:14 PM, snipped-for-privacy@aol.com wrote:

yes, two panels in the same house. the garage is detached and is fed off the pole. typical ag setup. One meter.
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snipped-for-privacy@aol.com wrote:

Yes mine are two separate structures fed with two sets of wire from one transformer. To me the OP sounded like the main was run to two main panels in one building.
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Nothing wrong with that if the power company okays it. But, as I said, I'm not sure I understand the hookup as it was described. But it sounded to me like it would be the same as if a neighbor made a deal to run their power off your meter and then split the lower cost. All I'm saying is that method is really, really frowned upon around here.
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The Post Quartermaster wrote:

I doubt they would mind neighbors getting power from other neighbors. Because we are charged a flat kwh fee. No additional costs.
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Three wires to the house is acceptable unless (1) there is some other metallic path between the house and the pole (e.g. a phone line) or (2) you are working on the feeder and are subject to the 2008 or later NEC (existing feeders are OK). In either of those cases, you need a 4 wire feeder with an explicit EGC, and then at the house the grounds and neutrals are kept separate (with the grounding electrodes connected to the ground, not the neutral).

All grounding electrodes (e.g. ground rods) at a building must be interconnected. It is fine to have a single pair of ground rods for both panels; you could run the grounding electrode conductor to one panel and then a jumper to the next panel. If you have more than two rods, you still have to interconnect all the rods.
Also, in your situation with two main panels, the feeder neutral should be connected to the grounding electrode system at each of the main panels. This is the rare case where you interconnect ground and neutral at more than one location in a building.
Cheers, Wayne
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On Thu, 08 Jul 2010 12:29:08 -0500, Steve Barker

The code says disconnects for the building should be "grouped" and you can't have 2 sets of service entrance conductors. It sounds like you have 2 disconnects in one building that are separated. I can't think of any way to fix this that is easy and 2008 code legal. I would not stay awake nights worrying about it if it is otherwise compliant.
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On Jul 8, 1:25pm, snipped-for-privacy@aol.com wrote:

Bare with me as I'm not a electrician, but why would grounding rods needs to be interconnected on the two mains panels in one building? What's the difference between one building with two main and two house next too each other with two meters that attach to the same pole wires? Just curious about the logic.
Robin
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The logic is you want one ground reference. Dirt is not really a reference in spite of the fact that we call it ground. By bonding all the electrodes together, you create a single reference point.
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snipped-for-privacy@aol.com wrote:

You missed that the meter and main disconnect for the entire residence are located on the pole, not at the house. It's also not two sets of service entrance conductors, since those end at the disconnect at the pole, after that it's feeders to the two panels.
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wrote:

That just moves you from 230.70 to 225.33. They still have to be grouped in one location.
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wrote:

I'm not sure that I'm getting a clear picture of this setup from the OP. I see it as Wayne Whitney describes: The drop comes to the pole, down the pole into a meter, out of the meter into "the service disconnect", out of the service disconnect back up the pole, then across to house via one set of triplex. At the house the triplex is tapped into twice and feeding two separate panels.
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On 7/9/2010 6:21 AM, RBM wrote:

exactly right
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I think in this case the disconnect at the meter on the pole serves as the main panel and therefore the bonding of the neutral and ground should take place in there as well as your ground rod connection. So you should have four wires to each subpanel or metal conduit could serve as the grounding conductor with three wires. At the time these were installed three wires were permissible with the installation of a ground rod at each building. One shared ground rod was all that was needed at the time for both buildings.
I think that the rated life for a copper clad ground rod is 40 years. Other materials except stainless steel is less. You should probably install new rods for optimum lightning protection. Install two rods at least 16' apart and have one common grounding electrode conductor with one end going to one panel and the other end going to the other panel. Also install at least one new rod at the meter pole.
Is there a main breaker in each panel? Are the conductor sizes the same for each panel?
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On 7/9/2010 6:27 AM, John Grabowski wrote:

yes, and yes. at this time, everything involved is 4ga. And it's all the same building. Actually, the panels are only about 8 feet apart, but in different rooms.
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