Resi load calc.

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nizak

Senior Member
Could someone here take the time to check my service size calc. for a single family home. 120/240V1phase. Here's what I have for load: 3100 sq ft, (1)12KW range,(1)6.5KW cooktop,(1)5.5KW dryer,(1)3/4HP 120V attic fan,(1)1HP120VCirc pump and(1)1.5KW inline heater for jacuzzi tub,(1)13.5KW geothermal heat system. I will be putting (4) 20A circuits in the kitchen, the owners informed me that they use several high wattage countertop appliances at the same time. They may also look to finish 1200 sq ft of basement in the near future. I came up with 192A as is. Thanks to anyone willing to take the time.
 
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rodneee

Senior Member
nizak said:
I'm debating if I should price them out the job with a 200A service or a 400A.
Click to expand...

this house is 200 amp unless the buyer wants to "MAKE IT" 400 amp. we do so many needless upgrades to 400 amp it still boggles my mind....
 
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nizak

Senior Member
Being at approx 90% of the service rating didn't seem to leave much wiggle room if they look to put a hot tub on the deck next year. I'm just using this as a for instance,do many here plan for future load when they figure a service?Many contractors around here put in 200A , with gas appliances that's usually double what would be required and one wouldn't be concerned with future electrical needs. This just seemed to be one that was right at thae point of going either way.
 
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Volta

Senior Member
Location
Columbus, Ohio
I get 161 amps for the items listed, with the attic fan, jacuzzi heat and pump all as continuous. Adding in the required laundry circuit, and an assumed 12a furnace @ 120v brings it to 170 amps, by my numbers.

Four kitchen circuits, but no provisions for DW, Micro, or disposal.

No A/C?
 
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nizak

Senior Member
My mistake, there is a dishwasher, disposal, and microwave I guess I simply overlooked listing it as they are so common. As far as AC, I'm told it's not needed with the geothermal pump system. Thanks for catching my mistake.
 
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Volta

Senior Member
Location
Columbus, Ohio
That gives you (more than) four appliances, so they can now all be counted at 75% with the cooktop, so bonus- that only adds 2 amps!*

172 amps.

How about that geothermal pump system?


*(If DW, disp, and micro are 1200, 800, and 1440 va, respectively).
 
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nizak

Senior Member
What was your ? about the geothermal?? It's listed as 13.5KW. There is no electric back up heat that is being supplied by the GFA furnace.
 
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Volta

Senior Member
Location
Columbus, Ohio
nizak said:
What was your ? about the geothermal?? It's listed as 13.5KW. There is no electric back up heat that is being supplied by the GFA furnace.
Click to expand...

I was wondering what power would be needed for the system. Do we need to allow another 13.5KW for it?
What is 'GFA' furnace?
 
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nizak

Senior Member
When you came up with 170A in one of your previous posts was that including the 13.5KW geothermal? GFA= Gas Forced Air(Conventional style heat).
 
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Volta

Senior Member
Location
Columbus, Ohio
Ok, being a little more careful, but still with some assumptions, these are my numbers:

3100 + 1200 = 4300 sq ft * 3 va = 12900
12900 va + 1500 laundry + 6000 kitchen = 20400 va
20400: 1st 3000 + (17400 x .35 = 6090) = 9090 va SA and Lighting

9090 SA + Lighting
8000 Range
5500 Dryer
1440 Furnace??
13500 Geothermal
2070 = (1656 x 1.25 continuous) Attic fan
6600 = (5280 x 1.25 continuous) Jacuzzi pump
1875 = (1500 x 1.25 continuous) Jacuzzi heat
48075 = Items above

6500 = Cooktop
1200 = Dishwasher??
800 = Disposal??
1440 = Microwave??
7455 = Items above (9940 x .75) Section 220.53

48075 + 7455 = 55530
55530 / 240 = 231 amps @ 240 v
 
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