Typical single-line diagram for a 400A, 120/240V, single-phase, 3-wire service for a two-family dwelling, using a two-position compartmentalized multi-meter (Square D MP Meter-Pak) with a 200A tenant breaker serving each dwelling unit panel, with a BESS-ready 60A backup load panel for each unit per the 2025 California Energy Code, Section 150.0(s). Includes service and feeder conductor sizes in copper and aluminum, grounding electrode conductors, surge protection, PV-ready backfeed breakers, occupant-access notes, and the equipment shop drawing. Designed to NEC 2023. Instant PDF download.