NEC 220.82 Optional Method4,000 Sq Ft • Executive Estate with Pool & Dual EVSECode Compliant
400 Amp Service Load Calculation for 4,000 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 Demand306.8 Amps@ 240V Single Phase
Recommended Panel400 AmpsNEC Standard Rating
Service Feeder (Al)Dual ParallelTable 310.12 (75°C)
Minimum ConduitDualEMT / PVC Sch 40
Connected Appliance Profile & Nameplate Loads
Specific mechanical equipment ratings evaluated for this residential dwelling unit
Cooking EquipmentPro Induction Range + Double Convection Ovens (18,000 VA)
Clothes DryerElectric Dryers x2 (10,000 VA)
Water HeatingDual 50-Gal Electric Water Heaters (9,000 VA)
HVAC Primary Heating/CoolingDual 3.5-Ton Heat Pumps (12,000 VA total)
Electric Vehicle Supply (EVSE)Dual 48A EV Chargers (23,040 VA continuous)
Auxiliary Fixed AppliancesIn-ground Pool Pump & Heater (10,000 VA), Hot Tub (11,000 VA), Dishwashers x2 (3,000 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) | 12,000 VA | Subtotal Group | — |
| Small Appliance Circuits2 Circuits @ 1,500 VA • NEC 220.82(B)(2) | 4,500 VA | Subtotal Group | — |
| Laundry Branch Circuit1 Circuit @ 1,500 VA • NEC 220.82(B)(2) | 3,000 VA | Subtotal Group | — |
| Fixed & Fastened-in-Place AppliancesRange, Dryer, WH, DW, Disposal • 220.82(B)(3) | 62,000 VA | Subtotal Group | — |
| General Connected Load Subtotal | 81,500 VA | — | — |
| • First 10,000 VA of General Load | 10,000 VA | 100% | 10,000 VA |
| • Remainder above 10,000 VA | 71,500 VA | 40% | 28,600 VA |
| General Demand Load Subtotal | — | 220.82(B) | 38,600 VA |
| Heating & Air Conditioning (HVAC)Largest Non-Coincident Load • NEC 220.82(C) | 12,000 VA | 100% | 12,000 VA |
| Electric Vehicle Charger (EVSE)Continuous Load • NEC 625.42 | 23,040 VA | 100% / 125% | 23,040 VA |
| TOTAL CALCULATED DEMAND LOAD | — | Total / 240V | 73,640 VA • 306.8 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):Dual Parallel Sets of 2/0 AWG Copper THHN (or 500 kcmil)
Aluminum Conductor (XHHW-2):Dual Parallel Sets of 4/0 AWG Aluminum XHHW-2
Minimum Raceway / Conduit:Dual 2" Conduit Runs
Temperature Rating:75°C Terminations
Grounding & Bonding Electrode System
GEC to Water Pipe / Intersystem:1/0 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
- Calculated demand is 306.8A, perfectly matching a Class 320 / 400A residential service configuration.
- Parallel conductors: Per NEC 310.10(G), parallel service runs must be identically sized (dual 2" conduits each carrying 4/0 Aluminum or 2/0 Copper).
- The service splits into two separate 200A distribution panels (e.g. Panel A for interior lighting/living loads, Panel B for HVAC, pool, and EV charging).
Frequently Asked Code Questions
How does a 400 amp service actually work in a residential home?
A residential 400A service uses a "Class 320" meter socket rated for 320A continuous / 400A maximum. From the meter, dual 200A feeder runs enter two side-by-side 200A main breaker panels inside the residence.