Main service capabilities


Old 02-12-06, 06:28 AM
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Main service capabilities

My main service curently is a single 200 amp box. My house isn't that old (2 years or so) but some of the new houses have 2 200 amp boxes (so I would assume 400amps coming to the meter and into the house)

Is there any (easy) way to tell if my existing service would support a second 200 Amp main panel? I'm just trying to gauge the cost impact if I was to persue an upgrade some day. Would the electric company be able to tell me 0ver the phone or would I need someone to come out and look at the equipment I have? What would they be looking for?
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Old 02-12-06, 06:48 AM
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The easy answer is no.
It is extremely doubtful that a contractor would install the wiring capable of 400 amps and not install a 400 amp service. It would be ludicrous IMO.
200 to 400 is a VERY obvious difference.

You can tell us with detail what wires and conduits you have feeding your house and it is possible we can decipher what you have.
Old 02-12-06, 07:10 AM
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Can you tell us why you think you need 400 amp service. If your current box is full and only need more breaker spots that does not mean you need a 400 amp service. A sub panel off your existing panel might be all you need. There are many place on the net that will help you do a load calc to see if really need a 400 amp service.

Last edited by joed; 02-12-06 at 10:16 AM.
Old 02-12-06, 09:34 AM
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I do agree. Why do you think you need 400 amps? Because your neighbors do?

It seems that HUGE homes and 400 amp services are the new cool things to have.
Old 02-12-06, 02:05 PM
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Are you an all-electric home? If you have gas for stove or water heater or central heating, it would seem 200 is plenty. 400 amps is 96 KW. At the rates we pay, if you were running full load at 96 KW, it would cost about $15 per hour. At 3 hours per day, that would give you an electric bill of about $1300 per month!
Old 02-12-06, 03:05 PM
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I would be currious to know why you think you need a future upgrade to 400a? 200 will do most just fine. What are the things that you are planning to do that you would need an upgrade of that size?
Old 02-12-06, 06:32 PM
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Whoa..... I'm currently not looking to upgrade, I agree that 400A service is a lotta juice (and I DONT need that right now). I was just curious to see what capability I had. The difference I noticed was between builders. Toll Brothers built my house and installed a single 200 Amp panel. Houses of the same class (size, style etc) built by Van Meter have 2 200 Amp panels. I thought that the 2 panels (although only half full each) were a nice to have, it really made it organized and neat, as well as allowing PLENTY of room for expansion. (While my panel has 8 spaces left..) I was just wondering if the service to the house was there, and toll brothers just went cheap on the panels. Wouldn't be the first shortcut I've found in this house.... Anyway, I'm good with the 200 amp service I have, I was just curious and looking to learn something...

One other question: There is a note inside my panel (among all the fine print) that says "Max. sum of breaker rating per stab; 200 Amps" What does this mean? What's a "stab"?

I know that the panel is split into two 120 volt sides and I think that the breakers alternate which leg they are actually connected to. In other words if I look down the left column of breakers I think that every other one is actaully connected to the right side. So when I connect a 2 pole breaker it pulls power from both right and left legs, even though the breaker itself sits only on one side. Is this correct?
Old 02-12-06, 06:45 PM
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I think it's just that you didn't need it so they didn't install it. If they had gone to 400 you'd have know it, from the invoice! 400 amps is no small change.

Your theory is pretty accurate as to breaker configuration. The 200 amps per stab means you cannot put larger than a 200 amp breaker in the panel. It has nothing to do with the sum of all the breakers. That is a meaningless number.

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