Electrical-load planning is about simultaneous demand and safety margin, not simply adding every appliance label at full power. A transparent estimate helps identify when a qualified design review is needed.
Start with existing demand
List the loads that may operate together and estimate their normal demand. Distinguish running power from starting surge for motors, compressors, and pumps.
Add the proposed charger
Add the EV charger’s continuous power to the relevant household scenario, then apply the chosen headroom or diversity assumption. A 3 kW base load plus 7 kW charger is 10 kW before margin.
Check service capacity
Compare modeled demand with the service capacity and the rules used by the local utility or code. A simple arithmetic result cannot approve a circuit, panel, breaker, or conductor.
Use load management when appropriate
Managed charging, scheduling, and load shedding can change simultaneous demand. Document the control behavior and fail-safe state rather than assuming software will always prevent overload.
Sources
The figures and rules in this guide are checked against:
- NFPA 70: National Electrical Code — National Fire Protection Association
- Home Safety — Electrical Safety Foundation International
- Charging Electric Vehicles at Home — U.S. DOE Alternative Fuels Data Center
- Home Charging Installation — Tesla Support