ADU Electrical Wiring in Los Angeles: Costs & Permits

Los Angeles is in the middle of an ADU boom. From garage conversions in Highland Park to backyard cottages in the San Fernando Valley, homeowners are adding accessory dwelling units to house family, earn rental income, or expand their living space. But behind every comfortable, code-compliant ADU is one detail people underestimate: the electrical wiring. Getting it right keeps your unit safe, your permit on track, and your project on budget.

Why ADU Electrical Wiring Is Different

An ADU is essentially a second home on your property, so its electrical system has to support a full kitchen, bathroom, heating and cooling, lighting, and outlets - all to current California code. That means more load than a simple room addition. Most ADU electrical wiring projects in Los Angeles involve running a new circuit set, adding a dedicated sub-panel, and confirming your main service can carry the extra demand. Skipping the load calculation is the single most common reason ADU electrical work fails inspection.

Does Your ADU Need Its Own Panel or Meter?

This is the question we hear most. In most LA conversions, the ADU is fed from the home's existing service through a new sub-panel rather than a separate utility meter. A few factors decide the right setup:

• Existing service size. A 100-amp main panel often can't carry a whole second dwelling. Many ADUs require a panel upgrade to 200 amps before wiring can begin.
• Separate metering. If you want the tenant billed directly, LADWP or your utility may allow a second meter - but it adds cost, time, and utility coordination.
• Distance from the main panel. A detached ADU at the back of the lot needs properly sized feeders and often a trench for underground conductors.
• Total load. Electric range, heat pump, EV charger, and a tankless water heater can push demand quickly - this is where a professional load calculation matters.

What an ADU Electrical Rough-In Includes

Once the design is set, the wiring work in a typical Los Angeles ADU breaks down into a few stages:

• Feeder and sub-panel. Running the feeder from the main service and mounting a correctly sized sub-panel inside the ADU.
• Branch circuits. Dedicated circuits for the kitchen, bathroom, HVAC, and small-appliance loads, with the right wire gauge for each.
• Outlets, switches, and lighting. Code-required spacing, plus GFCI and AFCI protection where the California Electrical Code demands it.
• Smoke and CO alarms. Hard-wired, interconnected detectors are mandatory in every ADU.
• EV and future-proofing. Many owners add a 240V circuit now so an EV charger or heat pump can be installed later without re-opening walls.

Permits and Inspections in Los Angeles

ADU electrical work is permitted and inspected separately from the structural and plumbing trades. In the City of Los Angeles you'll pull an electrical permit through LADBS; in Pasadena, Burbank, Glendale, and other cities the local building department handles it. Expect at least two inspection points - a rough-in inspection before walls are closed, and a final inspection once devices and the panel are energized. Working with a licensed contractor who knows your city's plan-check process keeps the timeline predictable. Our Pasadena electrician team handles permitting and inspections across the LA area every week.

What Does ADU Electrical Wiring Cost?

Pricing varies widely with the size of the unit, the distance from the main panel, and whether a service upgrade is needed. As a realistic planning range - not a quote - most Los Angeles ADU electrical projects land somewhere between $4,000 and $12,000, with detached units and required panel upgrades at the higher end. Costs and any rebates change over time and should be verified for your specific project. The biggest swing factors are:

• Whether your main panel needs upgrading to handle the added load
• Attached garage conversion versus a detached new-build ADU
• Trenching distance for underground feeders to a backyard unit
• High-demand appliances like EV chargers, heat pumps, or electric ranges

If you discover existing problems during the project - outdated wiring, an overloaded panel, or unsafe junctions - it's worth folding those electrical repairs into the same permit while the walls are open.

Frequently Asked Questions

Does an ADU need its own electrical panel?

Usually it needs its own sub-panel fed from the main service, not a fully separate panel. A separate utility meter is optional and only needed if you want the tenant billed directly.

Do I need to upgrade my main panel for an ADU?

Often, yes. Many older LA homes have 100-amp service that can't safely carry a second dwelling. A licensed electrician runs a load calculation to confirm whether a 200-amp upgrade is required before wiring begins.

Is a permit required for ADU electrical work in Los Angeles?

Yes. ADU electrical work requires its own permit and passes a rough-in and a final inspection. Unpermitted work can block your certificate of occupancy and create problems when you sell or insure the property.

Can I convert my garage to an ADU using the existing wiring?

Rarely as-is. Garage circuits are typically minimal and not rated for a full dwelling. Expect new branch circuits, a sub-panel, and code-required GFCI/AFCI protection, smoke and CO alarms, and proper outlet spacing.

How long does ADU electrical wiring take?

The wiring itself often takes a few days to about a week, but the full timeline depends on permit approval, inspection scheduling, and whether a service upgrade is part of the job.

Get Your ADU Wired Right the First Time

911 Construction & Electric Inc. is a licensed, bonded, and insured C-10 electrical contractor (CA Lic. #1027421) serving Los Angeles, Pasadena, Burbank, Glendale, Altadena, the San Fernando Valley, and nearby cities. We handle ADU load calculations, sub-panels, permits, and inspections from start to finish. Contact us for a free estimate or call 747-255-8595 to get your ADU electrical project moving.