NEC 220.82 Optional Method1,500 Sq Ft • Single-Family Ranch / Suburban HomeMarginal Capacity
100 Amp Service Load Calculation for 1,500 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 Demand84.5 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 EquipmentElectric Range (12,000 VA)
Clothes DryerGas Dryer (600 VA)
Water HeatingNatural Gas Tank (0 VA)
HVAC Primary Heating/Cooling2.5-Ton Central AC (4,200 VA) + Gas Furnace (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) | 4,500 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) | 16,200 VA | Subtotal Group | — |
| General Connected Load Subtotal | 25,200 VA | — | — |
| • First 10,000 VA of General Load | 10,000 VA | 100% | 10,000 VA |
| • Remainder above 10,000 VA | 15,200 VA | 40% | 6,080 VA |
| General Demand Load Subtotal | — | 220.82(B) | 16,080 VA |
| Heating & Air Conditioning (HVAC)Largest Non-Coincident Load • NEC 220.82(C) | 4,200 VA | 100% | 4,200 VA |
| TOTAL CALCULATED DEMAND LOAD | — | Total / 240V | 20,280 VA • 84.5 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 reaches 84.5A, utilizing 84.5% of the 100A panel capacity.
- This installation is code-compliant but marginal; continuous loads or simultaneous high usage may cause nuisance tripping or heat buildup.
- No spare capacity exists for future electrification (electric vehicle, induction cooktop, or heat pump water heater).
Frequently Asked Code Questions
Is 84.5 amps acceptable on a 100A service panel?
Yes, because NEC 220.82 demand calculations represent calculated peak diversified load. However, electricians consider anything above 80% capacity marginal for future additions.
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