NEC 220.82 Optional Method3,200 Sq Ft • Modern Electrified Residence with Multi-Vehicle FleetCode Compliant
400 Amp Service for Dual EV Chargers & Cold-Climate Heat Pumps
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 Demand253.5 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 EquipmentInduction Range & Convection Microwave (14,000 VA)
Clothes DryerElectric Heat Pump Dryer (2,000 VA)
Water HeatingHeat Pump Water Heater (1,500 VA)
HVAC Primary Heating/CoolingDual Inverter Heat Pumps: 3.5-Ton + 2.5-Ton with 10kW Emergency Backup (16,000 VA)
Electric Vehicle Supply (EVSE)Two 48A EVSEs (23,040 VA continuous)
Auxiliary Fixed AppliancesDishwashers x2 (3,000 VA), Garbage Disposal (900 VA), Workshop Tools (4,000 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) | 9,600 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) | 25,400 VA | Subtotal Group | — |
| General Connected Load Subtotal | 39,500 VA | — | — |
| • First 10,000 VA of General Load | 10,000 VA | 100% | 10,000 VA |
| • Remainder above 10,000 VA | 29,500 VA | 40% | 11,800 VA |
| General Demand Load Subtotal | — | 220.82(B) | 21,800 VA |
| Heating & Air Conditioning (HVAC)Largest Non-Coincident Load • NEC 220.82(C) | 16,000 VA | 100% | 16,000 VA |
| Electric Vehicle Charger (EVSE)Continuous Load • NEC 625.42 | 23,040 VA | 100% / 125% | 23,040 VA |
| TOTAL CALCULATED DEMAND LOAD | — | Total / 240V | 60,840 VA • 253.5 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):Dual Parallel Sets of 2/0 AWG Copper THHN
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 253.5A, exceeding 200A service by 53.5A.
- A 400A service (Class 320 meter feeding dual 200A panels) allows simultaneous overnight charging of two electric vehicles at maximum speed (48A each) without load shedding.
- Panel allocation: Panel 1 handles house lighting, kitchen, and heat pumps; Panel 2 handles the garage EV chargers, workshop, and outdoor loads.
Frequently Asked Code Questions
Can two EV chargers share a 200 amp electrical panel?
Yes, but only if they utilize dynamic power sharing (such as Tesla Wall Connector power sharing) where both cars dynamically share a single 50A or 60A circuit, or if the home has low overall electrical demand.