ADU Electrical Cost in San Diego (2026 Contractor Guide)
San Diego is the ADU capital of California. Whether you're building a garage conversion, a detached JADU, or a full 1,200 sq ft unit, the electrical scope is the single biggest variable in your budget. Here's how to plan it right.
For a typical San Diego ADU in 2026, budget $8,500 to $22,000 for electrical, depending on whether you're converting a garage or building detached, whether you need a service upgrade, and whether SDG&E is setting a separate meter. That's the wire, panel, permit, and fixtures — not solar, not the EV charger, not the low-voltage.
2026 ADU electrical budget ranges
| ADU Type | Typical Electrical | Includes |
|---|---|---|
| Garage conversion (JADU, <500 sq ft) | $6,500 – $11,000 | Subpanel, wiring, fixtures, permit |
| Attached ADU (500–800 sq ft) | $9,000 – $15,000 | Subpanel + service upgrade if needed |
| Detached ADU (800–1,200 sq ft) | $12,000 – $22,000 | Trenching, subpanel, service upgrade |
| ADU with separate SDG&E meter | +$3,500 – $7,500 | New service drop coordination |
| ADU + EV charger + heat pump | +$1,500 – $4,000 | Load calc, dedicated circuits |
Subpanel vs. separate meter
The biggest early decision. A subpanel off the main house is cheaper (typically $3,000–$6,000 less) and faster — but the ADU tenant shares the utility bill with the main house. A separate SDG&E meter lets you bill the ADU independently (huge for rentals) but adds coordination time, permit fees, and often a 200A → 400A service upgrade on the main property.
What the electrical scope actually covers
- —Trenching and conduit from the main service to detached ADUs (3-foot depth for feeders in CA)
- —Feeder sizing — typically #2 aluminum or #4 copper for a 100A subpanel
- —100A or 125A subpanel inside the ADU
- —Rough-in: outlets, switches, lighting, smoke/CO, exhaust fans
- —AFCI/GFCI protection where code requires (bedrooms, kitchens, baths, laundry)
- —Dedicated circuits for HVAC, mini-split, water heater, EV charger
- —Final trim, fixtures, and utility coordination
Where ADU projects blow the budget
- —Discovering mid-build that the main panel is full and needs a 200A → 400A upgrade
- —Undersized feeder run to a detached unit (no headroom for future EV/heat pump)
- —Skipping a load calc — then having to re-pull permits when heat pump is added later
- —Choosing a separate meter after the trench is already backfilled
- —Old Zinsco or FPE panels on the main house that must be replaced before ADU can energize
Plan for the future
Even if your first tenant doesn't drive an EV or run a heat pump, size the ADU feeder and subpanel so those loads can be added without re-trenching. The marginal cost at rough-in is small — the retrofit cost 3 years later is not.
Quick answers, straight up.
How much does electrical cost for an ADU in San Diego?
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In 2026, typical San Diego ADU electrical runs $6,500 to $22,000 depending on size, whether it's detached, and whether SDG&E is setting a separate meter. Add $3,500–$7,500 for a separate meter and any service upgrade on the main property.
Do I need a separate meter for my ADU?
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Not required — many San Diego ADUs run off a subpanel from the main house. A separate SDG&E meter is worth it if you plan to rent the ADU and want tenants on their own utility bill.
What size subpanel does an ADU need?
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Most 1,000–1,200 sq ft San Diego ADUs are wired with a 100A or 125A subpanel — enough for AC/heat pump, induction range, water heater, and a Level 2 EV charger with load management.
Does an ADU require a permit?
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Yes. Every San Diego ADU requires building, electrical, plumbing, and mechanical permits. The city offers pre-approved ADU plan sets that streamline the process — we work with those regularly.
Can I add an EV charger and heat pump to my ADU later?
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Yes, if the feeder and subpanel were sized for it up front. Retrofitting after the trench is backfilled is expensive — always plan for future loads at rough-in.
