How to Calculate Service Load for Upgrading from 100 to 200 Amps
Complete electrical demand load breakdown following NEC Article 220.82. Formally verified for electrical permit submissions, service disconnect sizing, and utility service drop requirements.
Connected Appliance Profile & Nameplate Loads
Specific mechanical equipment ratings evaluated for this residential dwelling unit
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) | 6,000 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) | 24,200 VA | Subtotal Group | — |
| General Connected Load Subtotal | 34,700 VA | — | — |
| • First 10,000 VA of General Load | 10,000 VA | 100% | 10,000 VA |
| • Remainder above 10,000 VA | 24,700 VA | 40% | 9,880 VA |
| General Demand Load Subtotal | — | 220.82(B) | 19,880 VA |
| Heating & Air Conditioning (HVAC)Largest Non-Coincident Load • NEC 220.82(C) | 5,600 VA | 100% | 5,600 VA |
| Electric Vehicle Charger (EVSE)Continuous Load • NEC 625.42 | 9,600 VA | 100% / 125% | 9,600 VA |
| TOTAL CALCULATED DEMAND LOAD | — | Total / 240V | 35,080 VA • 146.2 A |
Service Conductor & Grounding Sizing Schedules
Minimum wire gauges and raceway sizes compliant with NEC Table 310.12 and Table 250.66
Master Electrician Inspection & Installation Notes
- The home’s post-upgrade demand of 146.2A confirms that the existing 100A panel is completely inadequate and would trip under peak load.
- Upgrading to 200A provides a safe 53.8A cushion, enabling simultaneous cooking, EV charging, and heat pump operation.
- Key scope of work for the electrician: Replace meter base with 200A socket, upgrade service mast/conduit to 2", pull 4/0 aluminum conductors, install 200A 40-circuit main breaker panel, and bond two new 5/8" copper-clad ground rods.
Frequently Asked Code Questions
What are the main signs that I need to upgrade from 100 to 200 amps?
Key indicators include: planning to install a Level 2 EV charger, converting from gas to an electric heat pump or induction range, lights flickering when the AC starts, or a panel that has zero open breaker slots remaining.
Does the electric utility company charge to upgrade to 200 amps?
Utility fees vary. Many utilities will disconnect and reconnect the service drop for free during a permitted panel replacement, but may charge if the overhead service drop wire from the utility pole to the house must be enlarged.