larger subpanel or multiple smaller panels?


Old 04-04-05, 08:36 AM
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larger subpanel or multiple smaller panels?

I am in the process of wiring my own home. This is something I have done before, but with a smaller home with smaller power requirements. (This home is 4000 sq. ft.) I have already installed 200 amp service and one temporary receptacle for use during construction. This has been inspected, connected and in use. I already know that I will not have enough spaces in the main panel for the circuits that I will require, and I will install at least one sub panel. My question at this point is would it be more practical to install two or more smaller subpanels or one larger (100 amp?)subpanel?

Main Service is in wall of attached garage. A wire run of about 60-70 ft would get me into the mechanical room in the basement. I figured that would be the best place to put sub panel(s). In that area will be furnace, AC, small boiler with circulating pumps for hot water/radiant heat, and well pump. Other than this mechanical room, the rest of the basement will be finished living space.

Coming from this area would also be a shorter run for all of basement wiring and some of main floor wiring (including electric stove and dryer), and hot tub and pool circuits than going all the way back out to garage main.

Any suggestions would be appreciated.
Thanks in advance,
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Old 04-04-05, 10:59 AM
Join Date: May 2001
Location: Dry Side of Washington State
Posts: 738
Sounds like a good idea to install a sub panel!
Old 04-04-05, 12:26 PM
Join Date: Jun 2004
Location: Ontario, Canada
Posts: 96
I would go with a 24 slot panel, if not larger. The smaller panels are not cheaper. Also, in a modern house you will need to extra space, basement workshop, central vacuum, sump pump, etc, etc. It's just amazing how many circuits you need to fully met code these days.

As an aside, how many breakers does a modern house really need? It's more than 40, that's for sure.

I would recommend buying one of the kits which come with breakers. They are a good deal. Around here the kits come with either have 10 15 amp breakers, or an assortment of breakers (some 15 amp, some 20 amp, a couple of double 20 and 30 amp breakers, etc). Pick which one is good for you.

One final point, sounds like you need at least a 100 amp sub-panel. It's better to keep the larger loads (things like stove, dryer, AC) on the main panel. Since these three alone eat up a large part of the 100 amps available at the sub-panel.
Old 04-04-05, 01:45 PM
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Thanks for the advice, I will check into the kits. It sounds like a good way to save a few bucks.

I guess I should have been a little clearer in my original question though. When I was asking if I should go with larger or smaller, I was meaning amperage. For example one 100A or two 60A. Which would be more practical?
Old 04-04-05, 02:45 PM
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Join Date: Jun 2003
Location: Anderson, IN
Posts: 412
Will a 200A service be sufficient for the house? Has anyone done a load calculation on the building to see if you might need a larger service? this is a large house and it might be such that the load requirements call for a larger service. If not, I would put as large of a panel in for subs as I could. You will never cuss yourself for putting in too many breaker spaces (the opposite is not always true) I might even put in another 200A main 40 space panel in the basement. At the bare minimum a 32 space 100A sub, however, I would suspect that with a stove, hot tub, boiler, dryer, pool, and gp and lighting circuits you will be close to maxing out a 100 amp panel.
Old 04-04-05, 03:18 PM
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The inspector had the same question about the service requirement, so I had an electrician do the load calculation before the service was installed.

Wouldn't I be getting into a lot more expense for larger wire and conduit for 200A or 100A subs as suggested?
Old 04-05-05, 11:48 AM
Join Date: Jun 2004
Location: Ontario, Canada
Posts: 96
I went with 3 smaller sub-panels. A 60 amp 24 slot panel for the basement (including outside light and outlets, workshop, office/computer room, central vacuum, sump dump, etc, etc). A small 4 slot 20 amp panel just for the swimming pool (pump, filter, lights) and a small 30 amp 8 slot panel for my home theater (a work in progress, and will be for awhile!).

The main service is 200 amps, 40 slot panel, but my house is smaller than the one you are talking about.
Old 04-05-05, 01:10 PM
Join Date: Feb 2002
Location: port chester n y
Posts: 2,117
I suggest you install two 100-map Feeders to the M-R-- this will essentaily "extend" the 200-amp Service in the garage to the location were the major loads will connect.

You will need X-number of circuit-breakers no matter where they are located, and the cost-differences between a 100-amp cable and a 60-amp cable ,and the two large/small sub-panels is not excessive, and worth the additional expence.

Also., you can neatly balance the loads on the two Feeders,a 40 load on Feeder "1", a 35 amp load on Feeder "B", etc.

Good Luck & Enjoy the Experience!!!!!!!!!
Old 04-05-05, 02:55 PM
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Thanks, but I'm not sure I understand the terminology. Is two 100A feeders two 100A subpanels running four wires for each or just two 100A breakers in service panel with the wires feeding one subpanel plus neutral and isolated ground.

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