Combination Meter Main
Also known as: Combo meter mainMeter-main comboCombination service equipment
In California, the standard residential service entrance configuration is a "combination meter main" — a single enclosure mounted on the outside of the home that contains the PG&E meter, the main service disconnect breaker, AND the panel that distributes power to individual circuits. Everything in one box on the exterior wall.
This differs from many other states, where the meter is in a separate exterior enclosure and the main panel sits inside the home (basement, garage, utility closet). California's combination configuration is partly an artifact of building codes that favor outdoor disconnects, partly seismic considerations, partly historical PG&E preference.
This is what you'll see on virtually every home in Santa Cruz County. If you're researching electrical work and the photos online show a separate meter and a separate indoor panel, that's an out-of-state configuration — not what's installed at your house. Permits, code, and PG&E coordination in California all assume the combination configuration unless specifically called out.
When we describe a panel upgrade, we mean the combination meter main — replacing all three components (meter base, disconnect, and panel) in one operation. The 2026 Greenbook's like-for-like rule applies to combination meter mains specifically.
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