STANDARD METHOD-SINGLE FAMILY DWELLING
ELECTRICAL SIZING CALCULATIONS
1. General Lighting & Receptacle Loads. NEC 220-3(b)
Not including open porches, garages, unused or unfinished spaces not adaptable for future use 		3 VA x
 __________
(sq. ft.) 		1 .
2. Small Appliance Branch Circuits. NEC 220-16(a)
Al least 2 small appliances branch circuits must be included. NEC 210-11(c)1 		1500 VA x
 __________
(min. 2) 		2 .
3. Laundry Branch Circuit(s). NEC 220-16(b), 220-4(c)
At least 1 laundry branch circuit must be included.  		1500 VA x
__________
(min. 1) 		3 .
4. Add lines 1, 2 and 3 4 .

5. _____________ - 3000=__________________________ VA
    (line 4) 		5 .

6. _______________________ x 0.35=_________________ VA
    (line 5) 		6 .
7. TOTAL General Lighting and Receptacle Load

3000 + _____________________ = __________________ VA
                       (line 6)                          

 		7 .
8. Fastened-In-Place  Appliances. NEC 220-17
Use nameplate rating. Do not include electric ranges, clothes dryers, space-heating or A/C equipment


water heater:___________________ (in VA's)

compactor:    ____________________

dishwasher: ____________________

garbage disposal: ________________

_____________: ________________

_____________:_________________

If fewer than 4 units, place total volt-amps (add the values) on line 8.
Or, 
If 4 or more than units, multiply total volt-amps x 75%,

__________________________x 0.75 =_______, enter on line 8
(volt-amp for 4 or more units)

8 .
9. Clothes Dryers. NEC 220-18
If not present >>skip. Otherwise, use 5000 watts or nameplate rating whichever is larger (no derating required for up to 4 dryers) 		9 .
10. Ranges, ovens, Cooktops and other cooking appliances over 1750 watts. NEC 220-19. If not present >>skip. Otherwise, use Table 220-19 along with notes 10 .
11. Heating or Air Conditioning. NEC 220-19.
  1. Compare between heat and cooling- eliminate the smaller.
  2. Include the air handler when using either one. 
  3. For heat pumps, include the compressor and the max. amount of electric heat which can be energized with the compressor running
11 .
12. Largest motor (only one). NEC 220-14, 430-24
Multiply the largest motor volt-amps x 25%

_____________________x 0.25= ___________ enter on line 12
(largest motor v-a) 		12 .
13. TOTAL Volt-Amp Demand Load: Add lines 7 through 12 13 .
14. MIN. Amperes for Service (Total v-a / voltage)=

(Line 13) / 240V (voltage= 240, for 120/240V service)=

_____________ / 240V=  ________________ AMPS


14 .
15. MIN. Size for Service Conductors/Feeders. NEC 240-6(a). Use next STANDARD size fuse or breaker . 15 .
16. Size of Service and/or Feeder Conductors. 
Use 310-15(b) for the service conductors up to 400A.
Rating > 400 amps; Use Table 310-16 . MIN. SIZE of CONDUCTORS= 		16 .
17. Size of Neutral Conductor. NEC 220-22
  1. NEC 310-15(b) allows neutral to be smaller than the ungrounded (hot) conductors, provided 215-2, 220-22 and 230-42 are met. 
  2. Size the neutral by finding the max. unbalanced load
  3. Neutral cannot be smaller than the required grounding electrode conductor specified in Table 250-94 . MIN. SIZE of NEUTRAL CONDUCTOR=
17 .
20. Size of Grounding Electrode Conductor (GEC). NEC, Table 250-94 . MIN. SIZE of GEC= 18 .

See an example calculation for this sizing method
v-a= volts-amperes=watts
To find amperage of 1-phase appliances when HP (horse power) and voltage is known; use Table 430-148
Information to gather before staring load calcs.