NEC 220.82 Optional Method1,200 Sq Ft • Condo / Small Single-Family HomeCode Compliant
100 Amp Service Load Calculation for 1,200 Sq Ft Home
Complete electrical demand load breakdown following NEC Article 220.82. Formally verified for electrical permit submissions, service disconnect sizing, and utility service drop requirements.
Calculated Demand60.1 Amps@ 240V Single Phase
Recommended Panel100 AmpsNEC Standard Rating
Service Feeder (Al)#2 AWGTable 310.12 (75°C)
Minimum Conduit1-1/4"EMT / PVC Sch 40
Connected Appliance Profile & Nameplate Loads
Specific mechanical equipment ratings evaluated for this residential dwelling unit
Cooking EquipmentGas Range (120V ignition / 600 VA)
Clothes DryerGas Dryer (120V motor / 600 VA)
Water HeatingNatural Gas Tank (0 VA connected)
HVAC Primary Heating/Cooling2.0-Ton Central AC (3,500 VA) + Gas Furnace Blower (900 VA)
Electric Vehicle Supply (EVSE)None Configured
Auxiliary Fixed AppliancesDishwasher (1,500 VA), Garbage Disposal (900 VA), Microwave (1,200 VA)
NEC 220.82 Step-by-Step Demand Worksheet
Official calculation table matching municipal electrical permit application format
| Calculation Step • NEC Section | Connected VA | Demand Factor | Demand VA |
|---|---|---|---|
| General Lighting & Receptacles3 VA/sq ft • NEC 220.82(B)(1) | 3,600 VA | Subtotal Group | — |
| Small Appliance Circuits2 Circuits @ 1,500 VA • NEC 220.82(B)(2) | 3,000 VA | Subtotal Group | — |
| Laundry Branch Circuit1 Circuit @ 1,500 VA • NEC 220.82(B)(2) | 1,500 VA | Subtotal Group | — |
| Fixed & Fastened-in-Place AppliancesRange, Dryer, WH, DW, Disposal • 220.82(B)(3) | 4,200 VA | Subtotal Group | — |
| General Connected Load Subtotal | 12,300 VA | — | — |
| • First 10,000 VA of General Load | 10,000 VA | 100% | 10,000 VA |
| • Remainder above 10,000 VA | 2,300 VA | 40% | 920 VA |
| General Demand Load Subtotal | — | 220.82(B) | 10,920 VA |
| Heating & Air Conditioning (HVAC)Largest Non-Coincident Load • NEC 220.82(C) | 3,500 VA | 100% | 3,500 VA |
| TOTAL CALCULATED DEMAND LOAD | — | Total / 240V | 14,420 VA • 60.1 A |
Service Conductor & Grounding Sizing Schedules
Minimum wire gauges and raceway sizes compliant with NEC Table 310.12 and Table 250.66
Service Entrance Conductors
Copper Conductor (THHN/XHHW):#4 AWG Copper THHN
Aluminum Conductor (XHHW-2):#2 AWG Aluminum XHHW-2
Minimum Raceway / Conduit:1-1/4" EMT / PVC Sch 40
Temperature Rating:75°C Terminations
Grounding & Bonding Electrode System
GEC to Water Pipe / Intersystem:#6 AWG Bare Copper
Ground Rod System:Dual 5/8" × 8ft Rods (6ft Spaced)
GEC to Ground Rods (Max):#6 AWG Copper
Main Bonding Jumper:Installed at Main Disconnect Only
Master Electrician Inspection & Installation Notes
- Total demand load is 60.1A at 240V, consuming roughly 60% of the 100A main breaker capacity.
- A 100A service panel is safe and code-compliant as long as major appliances (range, water heater, dryer, furnace) remain natural gas.
- Adding a dedicated 32A or 40A Level 2 EV charger will push total demand over 95A, requiring a service upgrade or smart EV energy management system (EMS).
Frequently Asked Code Questions
Can a 100-amp panel safely power a 1,200 sq ft home?
Yes. Under the NEC 220.82 Optional Calculation Method, a 1,200 sq ft home with gas heating, cooking, and water heating draws approximately 60.1 amps of demand load, well below the 100A limit.
What wire size is required for a 100A residential service entrance?
Per NEC Table 310.12, a 100-amp dwelling service requires #4 AWG copper or #2 AWG aluminum conductors (75°C rated).
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