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Old 02-11-2007, 12:25 AM   #1
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what service capacity to install?

My house has a rusted out electrical panel. The service hasn't been turned on yet so I want to take care of this.

If I get a box put in, what is the standard service capacity to install (is there a norm?) Or should I just match what's in there. I also count 18 used circuits, so I'd like to have some more blanks for future expansion. What do you recommend?

Should I use the existing breakers?
Should I eliminate the 2nd box and get it all into one?
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Old 02-11-2007, 05:39 AM   #2
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You need to do a demad load calculation on the house to determine what size service you need.

It starts with the sq footage of living space in the home measured by the outside dementions of the home. Include all floors.

Multiply this number by 3. so a 1000 sq foot home would be 3000 watts.

Next add 1500 for each small appliance branch circuit so that is 3000 and add 1500 for the washing machine .. 1500

Next you need to add major electrical appliances. Electric stove, Electric heat or AC, Electric water heater, Electric cloths dryer, ect

Demand factors can be used once you have the totals that will reduce your total load a bit. But this is a start.


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Old 02-11-2007, 06:53 AM   #3
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Not to step on JW's toes here, but IMO a demand load calc is not worth it here.
Go with 200 amps no question.
This is not simply a panel change though. It is a service change.
Everything from the connections at the top of the house, to the meter pan, service cables, panels and grounding electrodes MUST be replaced.
If you are new to this type of work then this is best left to a professional.

If this is a new house to you you will NOT be disappointed by the decision to upgrade.
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
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Old 02-11-2007, 07:58 AM   #4
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200 amp
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Old 02-15-2007, 03:33 PM   #5
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Service change

The existing service appears to be a 100-amp service
Allowing one 2-pole breaker as the sub-feed breaker for the sub-panel, there are still two 2-pole breakers discernible. Dryer and electric range?
there appear to be 2 twins and a full subpanel.
I get 28 breaker poles ... which would require a 30 circuit panel and allow little or no room for expansion.
As much as I don't usually recommend a 200-amp service because it is excessive, you are just moving in and HAVE to change the existing panel [and I bet the meter and cable are as dodgy] anyway, I would put in a 40-circuit 200-amp service if it was my house.
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