An accessory dwelling unit behind a South Florida house raises one electrical question before any other: does it run off the main house, or does it get its own meter? The answer shapes the panel schedule, the trenching, the load calculation, the conversation with FPL and, in some cases, what the zoning approval allows. This guide covers what Florida law says about ADUs, the utility metering rule that sometimes comes up, the two basic ways to power an ADU, and the permits involved.
It is written for builders, GCs, architects and owners planning a detached or attached ADU in Miami-Dade, Broward or Palm Beach. The building department with jurisdiction over the address, the zoning office and FPL each have a say, and each has the final word on its own part.
What Florida law says about ADUs
Section 163.31771, Florida Statutes, defines an accessory dwelling unit as an ancillary or secondary living unit with its own kitchen, bathroom and sleeping area (section 163.31771). The statute lets local governments allow ADUs in areas zoned for single-family residential use, tied to an affidavit that the unit will be rented at an affordable rate (section 163.31771). It says nothing about electric meters. Whether a city allows an ADU at all, and on what terms, is local zoning; start there before designing the electrical.
The utility metering rule
Florida Administrative Code Rule 25-6.049(5) requires individual electric metering by the utility for each separate occupancy unit of new commercial establishments, residential buildings, condominiums, cooperatives, marinas and trailer, mobile home and RV parks, for construction permits issued on or after January 1, 1981 (Rule 25-6.049). The rule defines an occupancy unit as the portion of a facility set apart from the rest by clearly determinable boundaries described in the rental, lease or ownership agreement for that unit (Rule 25-6.049). It lists exceptions, including hotels and motels, hospitals and nursing homes, dormitories and some time-share plans (Rule 25-6.049).
Whether a detached or attached ADU on a single-family lot counts as a separate occupancy unit under this rule is something we have not been able to verify. Do not assume either way. Ask FPL, through its Project Portal or your service planner, and ask the building official, before the design is fixed. The answer can decide between the two options below.
Option 1: a feeder from the main house
The ADU is supplied by a feeder from the main house's service or panel to a subpanel in the ADU. There is one meter and one FPL account.
- Load. The existing service has to carry the ADU on top of the house. That usually means a load calculation for the permit and often a panel or service upgrade.
- Existing dwellings. For an existing house, NEC 220.83 has an optional method for adding load, and 220.87 allows using one year of maximum-demand data at 125% plus the new load (EC&M on optional calculations).
- Detached units. The feeder runs underground to a separate building, so trench depth, the disconnect at the ADU and grounding at the second building all show up on the plans and the underground inspection.
- Billing. One account means the owner pays for the ADU's power. That is simple for a family unit and awkward for a rental.
Option 2: a separate service
The ADU gets its own service from FPL, with its own meter and account.
- Utility approval. FPL has to agree to serve it. New services go through FPL's Project Portal, and FPL cannot energize a new service until the local electrical inspection is complete and the inspecting office has notified it (FPL Project Portal; FPL Electric Service Standards, 2023).
- One service per building. Miami-Dade's inspection guidelines tell inspectors to verify that each building or structure has only one service, or that additional services are justified, under NEC 230.2 (Miami-Dade electrical inspection guidelines). A detached ADU is a separate building; an attached ADU with a second service raises that question directly.
- New service rules. A new dwelling service brings the 2020 NEC requirements for an outdoor emergency disconnect (230.85) and a surge protective device at the service (230.67) (Leviton, NEC 2020 changes).
- Site work. A separate service needs its own meter location, route and, in a flood zone, the required elevation. See the FPL new construction service process.
Side by side
| Feeder from the house | Separate service | |
|---|---|---|
| Meters | One | Two |
| Who decides | Building department (load, wiring) | FPL and the building department |
| Main house service | Must carry the ADU; upgrade often needed | Unchanged |
| Typical scope | Feeder, ADU subpanel, possible upgrade | New meter can, service equipment, FPL coordination |
| Open question | Whether the metering rule applies to your unit | Whether FPL and the city will allow a second service |
Inside the ADU
The ADU is a dwelling, so the dwelling rules apply: GFCI and AFCI protection, smoke alarms and the rest. Under the 2020 NEC, tamper-resistant receptacles extend to accessory buildings (406.12) (Leviton). See GFCI and AFCI requirements in Florida and NEC 2020 requirements for new homes. The 9th Edition of the Florida Building Code, with NEC 2023, is proposed to take effect Dec 31, 2026 (proposed rule); which edition applies depends on the application date.
Permits
- Zoning approval under the local ADU rules, where required.
- A building permit for the ADU, with an electrical sub-permit, or a stand-alone electrical permit for a conversion. See master permit vs electrical sub-permit.
- FPL's process for any new service.
- Owners doing the electrical themselves may qualify as owner-builders only on their own single- or two-family home for their own use, not for sale, under section 489.503(6) (section 489.503). An ADU built to rent raises questions to put to the department first.
Questions builders ask
Does Florida require a separate meter for an ADU?
The ADU statute is silent on meters (section 163.31771). Rule 25-6.049(5) requires individual metering for separate occupancy units of new residential buildings (Rule 25-6.049); whether that reaches your ADU is a question for FPL and the building official.
Can the ADU share the house's panel?
It can be fed from the house, usually to its own subpanel, if the service has the capacity. The load calculation answers that.
Which is cheaper?
It depends on the existing service, the distance and FPL's requirements. Price both once the metering question is answered.
Is a garage conversion an ADU?
If it gets a kitchen, bathroom and sleeping area, it meets the statute's description (section 163.31771). Zoning decides whether it is allowed.
Plan the ADU's power early
This is general information about Florida statutes and rules, not legal advice. Your local zoning code, the building official and the utility decide how an ADU on your lot is permitted and served.
For the rest of the permit picture, see our South Florida electrical permits guide. KRW Electric (EC13012832) handles new construction electrical, feeders, service upgrades and panel work across Miami-Dade, Broward and Palm Beach, and handles the electrical permit and inspections on its jobs. Send us the site plan and a photo of the main panel, or call (305) 359-7312.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
