ADU Electrical Panel Requirements in Los Angeles

Main Panel Capacity: 100A vs 200A Upgrades

Before adding an ADU, your electrician must perform a load calculation per NEC Article 220. Most older homes in Los Angeles have a 100-amp main breaker. Adding an ADU with electric HVAC, cooking, and water heating usually requires upgrading your main electrical panel to 200 amps or 400 amps.

Estimated ADU Electrical Installation Costs (Los Angeles 2026)

Installation Scope	Typical Cost Range	Best Suited For
100A Subpanel from Main House	$1,800 – $3,500	Family guest suites, home offices, pool houses
Dedicated Utility Meter (LADWP/SCE)	$4,500 – $7,500	Long-term rental ADUs needing separate tenant bills
Main House 200A Panel Upgrade	$2,500 – $4,500	Homes with existing 100A service adding an ADU
Underground Trenching & Conduit	$25 – $50 / linear ft	Detached ADUs located 30–100+ ft from main panel

Subpanel vs. Dedicated LADWP Utility Meter

When wiring an ADU, property owners have two primary options:

• 100A Subpanel (Fed from Main House): Most cost-effective option. Powers the ADU directly from the primary electrical panel.
• Dedicated Utility Meter (Dual Socket): Best for rental ADUs. Requires installing a dual-meter socket adapter and coordinating directly with LADWP or Southern California Edison (SCE).

2026 California Electrical Code & LADBS Permits

All ADU electrical work in Los Angeles requires permits from the Department of Building and Safety (LADBS). Key 2026 CEC requirements include:

• Dedicated AFCI and GFCI circuit breaker protection throughout the unit.
• Underground rigid conduit running from main house to detached garage/ADU.
• Title 24 solar-ready electrical infrastructure.