Best panel size for an EV charger or ADU
What is the best panel size for an EV charger or ADU in San Diego?
For most single-family homes adding an EV charger or heat pump, 200 amps is the practical standard. 400 amps suits all-electric homes with multiple EVs, or a main house plus ADU on one service. City of San Diego records for 2026 (Jan 1–Oct 15) show 58 residential 200A permits and 28 400A permits.
| Scenario | Usually enough |
|---|---|
| One EV + gas appliances | 200A (sometimes existing 100–125A with load management) |
| EV + heat pump + induction | 200A |
| Two EVs, all-electric, pool/spa | 400A |
| Main house + detached ADU on one meter | 200A–400A per load calc |
See 400A costs and EV-ready upgrades.
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Questions San Diego homeowners ask
Is 400A overkill?
For a typical home, yes. It pays off for all-electric homes, multiple EVs or an ADU sharing the service.
Does SDG&E fast-track upgrades?
SDG&E's Express Program covers qualifying residential projects up to 400A where no load is added and the meter stays on the same wall.
Size it right the first time
Get up to 3 quotes from licensed electricians.