An ADU needs its own circuits, usually a
sub-panel fed from the main house or its own
separate meter, and an
electrical permit. The first step is a
load calculation to see whether your main service can supply both buildings or needs an upgrade. Want help? See our
adu and garage wiring service.
Start with the Load Calculation
An ADU with a kitchen, bathroom, heat pump, laundry and EV charger is a real load. On many older LA homes with 100 amp service, the main service needs an upgrade to carry it.
Sub-Panel or Separate Meter?
| Setup | When it fits |
|---|
| Sub-panel fed from the main house | Most common. One utility bill. Main service must have capacity. |
| Main service upgrade + sub-panel | When the main service is too small for both buildings. |
| Separate meter for the ADU | Useful for rentals and separate billing. Requires utility coordination. |
Want a licensed electrician to take a look? Ready Electric answers 24/7.
Running Power to a Detached ADU
Feeders to backyard ADUs usually run underground at the depth code requires. Plan the route early, before landscaping and hardscape go in.
Permits and the Utility
ADU electrical work is permitted with the ADU, through LADBS in the City of LA or your city’s building department elsewhere. Service upgrades and separate meters also involve LADWP, Southern California Edison or your city utility.
Plan for Electrification
Many ADUs are all-electric, with a heat pump, induction cooking and a heat pump water heater. Size the panel for that from the start.
