Optional Method-Sizing Electrical Service

OPTIONAL 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 220-30(b)1 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 220-30(b)1 At least 1 laundry branch circuit must be included.	1500 VA x __________ (min. 1)	3	.
4. Appliances. NEC 220-30(b)3 & 4: Use nameplate rating of ALL appliances fastened-in-place, permenantly connected, or connected to a specific circuit), ranges, ovens, cooktops, motors and clothes dryers. Convert nameplate ampereage rating to volts-amperes by multiplying the amperage by voltage. Do not include any heating or air-condionting equipment in this section.
water heater:___________________ (in VA's) compactor: ____________________ dishwasher: ____________________ garbage disposal: ________________ range: _________________________ _____________:_________________		4	.
5. Demand Factors. NEC 220-30(b) for the total of lines 1 through 4. [(Total of lines 1-4) - 10,000] x 40% + 10,000 [_____________ - 10,000] x 0.4 = ____________ + 10,000=		5	.
6. Heating and/or Air Conditioning Loads. NEC 220-30(c) Use nameplate rating(s) in volt-amperess for all applicable systems in lines a through e below.
a. Air conditioning and cooling system(s), including heat pump compressors and supplemental heating, unless the controller prevents the compressor and supplemental heating from operating at the same time. _______________________ x 100% = ______________________ 6(a)= __________________
b. Electrical space heating equipment, if less than 4 separately controlled units: _______________________ x 65% = ______________________ 6(b)= __________________
c. Electrical thermal storage and other heating systems where usual load is expected to be continuous at full nameplate value: Systems qualifying under this selection shall not be figured under any other selction in 220-30(c): _______________________ x 100% = ______________________ 6(c)= __________________
d. Central electric spce heating equipment, including integral supplemental heating in heat pumps where the controller prevents the compressor and supplemental heating from operating at the same time. _______________________ x 65% = ______________________ 6(d)= __________________
e. Electrical space heating equipment, if 4 or more separately controlled units: _______________________ x 40% = ______________________ 6(e)= __________________
7. TOTAL Volt-Ampere Demand Load: Largest VA rating from lines 6(a) through 6(e) + Line 5 _________________________ + _______________________		7	.
8. MIN. Amperes for Service (Total v-a / voltage)= (Line 7) / 240V (voltage= 240, for 120/240V service)= _____________ / 240V= ________________ AMPS		8	.
9. MIN. Size for Service Conductors/Feeders. NEC 240-6(a). Use next STANDARD size fuse or breaker. Min. size shall be 100 amps.		9	.
10. Size of Service and/or Feeder Conductors. Use section 310-15(b) for the service conductors up to 400A. Rating > 400 amps; Use Table 310-16 . MIN. SIZE of CONDUCTORS=		10	.
11. Size of Neutral Conductor. NEC 220-22 NEC section 310-15(b) allows neutral to be smaller than the ungrounded (hot) conductors, provided 215-2, 220-22 and 230-42 are met. Size the neutral by finding the max. unbalanced load Neutral cannot be smaller than the required grounding electrode conductor specified in Table 250-94 . MIN. SIZE of NEUTRAL CONDUCTOR=		11	.
12. Size of Grounding Electrode Conductor (GEC). NEC, Table 250-94 . MIN. SIZE of GEC=		12	.