Glendale, CA · March 2025 – December 2025 · Glendale Water & Power / City of Glendale

Two new units at the back, three meters on the wall.

A Glendale lot with two newly built accessory dwelling units behind the house. Each unit got its own small array — five modules on one, eight on the other — and its own meter, so each was its own interconnection. The main house followed in the fall, and the third permission to operate came in at the end of December.

New accessory dwelling units in California are built with solar, and when each unit is separately metered the utility treats each as its own customer-generator. On this lot that meant two applications, two permits, two finals and two meter installations for two small arrays handed over as 5.2 kilowatts DC between them, and then a third set of everything for the main house. The roofs are simple; the count of meters sets the paperwork.

At a glance

Lot

Main house plus two new accessory dwelling units

ADU arrays

5 modules and 8 modules — 5.2 kW DC across the two units

ADU inverters

Microinverters, one per module

Main house

String inverter with optimizers, added in the fall

Meters

Three, one per dwelling

Interconnections

Three, each with its own permission to operate

Utility / AHJ

Glendale Water & Power / City of Glendale

The story

The two units were brand new — stucco still bright, doors not yet scuffed — and each had a plain composition shingle roof with a single clean slope. California's building energy code requires new dwellings of this kind to be built with solar, so the arrays were part of finishing the buildings rather than an upgrade to them: five modules on the smaller unit, eight on the larger, with a microinverter under each module.

What made the job a Glendale job was the wall at the end of the building: a bank of meter sockets side by side, one for each dwelling on the lot. Where each unit has its own meter, Glendale Water & Power sees each one as a separate customer-generator, and a separate customer-generator means a separate interconnection application, a separate permit with the city, a separate final and a separate meter to be set. The arrays were small. The paperwork was not.

The installation was booked for a Friday in the middle of March and moved a week by rain: the week before had washed out a queue of roof days and everything behind them shifted. The material was delivered to the site the day before, and on the twenty-eighth of March the crew was there by eight and both arrays went up the same day, rails on flashed feet, microinverters on the rails, modules over them.

Both units were then inspected together. The city's finals passed on the same Tuesday in May, and a week later Glendale Water & Power installed both generation meters. Each unit runs on microinverters with the monitoring at the module rather than a gateway on the wall, so switching on was the solar breaker and the AC disconnect, done as soon as the meters were in.

Then the main house. In November a third array went onto the original roof, this one on a string inverter with an optimizer under each module, and the same sequence ran a third time: plans and permit, installation, the city final at the end of November, and the utility's meter work. On the twenty-ninth of December the meter technician was at the property, the solar breaker was turned on with the homeowner present, and the third permission to operate was issued that day.

Three interconnections are three times the administrative work, and no contractor can compress that. Feeding the units from the main house on one meter would have made it one application — and would also have stopped them being separately metered dwellings, which is usually the whole point of building them. The meter count is settled when the units are designed, long before anybody talks about solar.

So if you are building accessory dwelling units in Glendale, ask two questions early: how many meters will the lot have, and who is filing the solar interconnection for each one.

How it ran

Two units from installation to meters in eight weeks; the main house followed on its own schedule.

What we did

• Installed both accessory-unit arrays in a single day: rails on flashed feet, microinverters, modules (C-10).
• Ran rooftop conduit to the disconnects and meter sockets on the end wall.
• Passed the city finals on both units on the same day.
• Switched both units on after the utility set the generation meters.
• Installed the main house array in the fall on a string inverter with optimizers.
• Met the utility's meter technician on site for the main house and had the system turned on the same day.

System specifications

Is your project like this one?

• You are building one or more accessory dwelling units and they will have their own meters.
• You want the units' solar done together, in one visit.
• You are on Glendale Water & Power and want to know what a second meter changes.
• You plan to add solar to the main house later, separately.
• You are scheduling roof work in a wet spring.

Cali Energy in Glendale

Frequently asked questions

Does each accessory dwelling unit need its own solar interconnection?

If it has its own meter, yes. Glendale Water & Power treats each separately metered dwelling as its own customer-generator, with its own application, its own permit and final with the city, and its own generation meter. On this lot that was three interconnections: two for the units and one for the house.

Why are the arrays so small?

Because the units are small and the code requirement is scaled to the dwelling. Five and eight modules cover what a one- or two-bedroom unit uses. The main house array, added later, is larger and sits on a different type of inverter.

How were the systems switched on?

On microinverters with the monitoring at the module, switching on is the solar breaker and the AC disconnect rather than anything on a screen, and that was done for both units as soon as the utility set their generation meters. For the main house, the utility's meter technician was on site and the breaker was closed with the homeowner present on the day permission was issued.

Does rain really move a solar installation?

It does. A wet week pushes every job in the queue, and this one moved from the twenty-first of March to the twenty-eighth. Roofing work is not done in the wet, and the crew that would have been here was finishing the jobs the rain had already delayed. Build a week of slack into a spring schedule.

What this would look like on your roof

Related

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• Two dwellings on one lot. Two of everything on the paperwork Studio City, CA · 2.32 and 1.45 kW · house and ADU, two work requests Solar
• The homes were finished. The utility's system said address not found North Hollywood, CA · 2.59 kW each · two ADUs, two interconnections Solar
• Seven hundred square feet. Two kilowatts Winnetka, CA · 1.95 kW AC-CEC · detached ADU Solar

This timeline reflects this property and this permitting path. Updated September 2026.