Has anyone seen a good form or spreadsheet around for single family residential service size calculation?
I made up a spread sheet for multi-family but it is a little awkward.
There was one from a member here a couple of years ago, but I don't remember who it was right at the moment.
In the mean time, Mike Holt's site has one here.
http://www.mikeholt.com/documents/calculations/formulas/ResidentialLoadCalculations.xls Roger
Dominion Power here in Va and NC has a 'load letter':
http://www.dom.com/customer/pdf/load_letter.pdf
[Try this one. The "a" with a mark above it should be an arrow. For some reson, this didn't translate but if you put it into Word, it is -->. ~Peter]
Dwelling Unit Calculations
(Use 120/240 volts)
Step 1. General Lighting
Area__________sq.ft. X 3 = ____________VA
Small Appliances [2 X 1500]____3000____VA
Laundry ____1500____VA
TOTAL ____________VA
First 3000 VA @ 100% ___-3000____VA X 1 = _________VA
3000 to 120,000 ____________VA X .35 _________VA
Over 120,000 ____________VA X .25 _________VA
TOTAL _________VA à________VA
Step 2. Appliances [Note: washing machine is included on the launder circuit.]
Cold Water Heater _________VA
Dishwasher _________VA
Garbage Disposal _________VA
Trash Compactor _________VA
Other _________VA
TOTAL _________VA à or
If more than 3 _________VA X .75 = à ________VA
Step 3. Heat vs. Cold
Air Conditioner @ 100% _________VA
Electric Heat _________VA Largest à ________VA
Step 4. Dryer
5000 or Nameplate VA [___amps X ___volts] [greater] à ________VA
Step 5. Stove
Result from 220-19 or 8000 VA à ________VA
Step 6.
Total of 1 thru 5: (6)________VA
(6)_________ = (7) ________Amps
240v
Step 7. Use Table 310-15(b)(6) if 120/240v
Or use 310-16 [if 3 phase or above 400 Amps}
Step 8. Apartment = 100 Amp service
House = 200 Amp service
Big house = 400 Amp service