A microgrid that cannot be permitted is a drawing.

On paper first

Three authorities, one drawing.

A residential microgrid answers to three authorities, and the design has to satisfy all of them before the first conduit is set. The building department of the city or county issues the electrical permit and sends the inspector; in County Line's area that is a different office for Thousand Oaks, Westlake Village, Calabasas, Hidden Hills, the City of Malibu, the City of Los Angeles for the Palisades, Brentwood and Bel Air, and the unincorporated parts of Los Angeles, Ventura and Santa Barbara counties, each with its own submittal habits. The gas utility or the propane supplier governs the fuel connection, which is plumbing work by a licensed contractor. And the electric utility, Southern California Edison or LADWP, governs anything that can push power toward the grid.

That last one is the piece homeowners rarely expect. A standby generator behind a transfer switch never exports, so the utility is not involved beyond the permit. A battery, a solar array and a bidirectional EV charger can all export, and in Edison territory they are interconnected under Rule 21, with an application, equipment that meets the listing requirements, and the utility's permission to operate before the system is switched on. LADWP has its own equivalent. The paperwork names every piece of equipment and its settings, which is one more reason a residential microgrid designed by one contractor as one system is easier to approve than five installations that each described a different house.

The one-line diagram is the document everyone reads. It shows the service entrance, the meter, the main disconnect, the transfer device or gateway, the generator, the battery inverter, the solar inverter, the EV gateway, the smart panel or critical-loads subpanel, and every conductor between them with its size and protection. The inspector uses it to check the installation; the utility uses it to see where the island forms and what can export; the next electrician, in fifteen years, uses it to understand what was built. County Line produces it before equipment is ordered and leaves it on the wall of the electrical room when the job is done.

Inspections come in layers. A rough inspection where conduit and boxes are visible on new construction; a final where the equipment is set, labeled and tested; sometimes a separate fire department sign-off for a propane tank or a battery system above a certain size, under the fire code's rules for energy storage. Labels matter more than people expect: a house with multiple sources has to tell a firefighter or a lineman, at the service, that there is a generator, a battery and solar, and where each disconnect is. The inspector checks the labels, and so does County Line before calling for the inspection.

None of this is a reason to skip the permit, and a system installed without one is a system an insurer and a buyer will both ask about. It is a reason to have the contractor who designed the system be the one who files, because the application and the drawing are the design, and the inspection is the first real test of whether the island forms the way the drawing says it does.

Back to the overview: Residential Microgrid.