Mission Hills, Los Angeles, CA · May – November 2022 · LADWP / LADBS
The load calculation ruled out a derate, so a 225-amp panel went in
A 12.8 kW SolarEdge system on a flat concrete tile roof. The plan was to de-rate the main breaker; the numbers said the house needed its full 200 amps, so the service panel was replaced instead.
This Mission Hills system is 12.8 kW DC with a SolarEdge HD-Wave inverter on a flat concrete tile roof, installed by Cali Energy in May 2022. LADBS asked for a load calculation to support de-rating the main breaker; it showed the house needed at least 200 amps, so the service panel was replaced with a 225-amp panel keeping a 200-amp main. Once the permits were corrected to match that work, the final was passed in November 2022.
At a glance
- System
- 12.8 kW DC / 11.4 kW AC, roof-mounted
- Inverter
- SolarEdge HD-Wave with rapid shutdown
- Roof
- Flat concrete tile
- Main breaker
- Stayed at 200 A; a de-rate was ruled out
- New service panel
- 225 A busbar, 200 A main, set into the wall
- Panel replaced
- 19 September 2022
- Final passed
- November 2022
The story
The system was planned at 12.8 kW DC on a flat concrete tile roof, with a SolarEdge HD-Wave inverter on the wall. On the scheduled install day in May 2022 the crew found that the layout in the plans did not leave the fire-access clearances the roof needed, and a new layout was drawn. How a solar job moves through the city is set out in solar permits with LADBS.
The plans connected the solar to the existing service panel with the main breaker de-rated to 175 amps. A smaller main breaker leaves room on the panel's busbar for the solar breaker. In August LADBS asked for a load calculation showing that the house could run on the smaller main, and Cali Energy prepared it from the plans and photos of the panel.
The calculation answered the question the other way. It showed that the main breaker had to stay at 200 amps at least, so a de-rate was not possible, and the way to make room for the solar was a new panel with a 225-amp busbar and a 200-amp main. The plans were revised to show it and approved on 8 September. A derate or a new panel is the usual fork — see when solar needs a panel upgrade.
The panel was replaced on Monday 19 September 2022. The new Siemens meter-main went into an opening cut in the stucco wall, with wire lath around it, ready to be plastered over.
The first final, on 30 September, came back with one correction, and it was about the paperwork rather than the work. A supplemental permit from the spring still described de-rating the panel to 175 amps, and a plan sheet still showed a 175-amp breaker. With a 225-amp panel in place the de-rate was not needed, so the permit had to be corrected or closed. On the same notice the inspector cleared the lath to be covered and approved the equipment on the roof.
The wall was patched around the panel that afternoon. At the second final, on 18 October, the work itself was in order; what was left was the paperwork. The solar permit still carried the words main breaker derate, and the supplemental permit was still open. In mid-November the permits were reissued to match the work, a solar permit and a separate permit for the panel replacement, and on 23 November 2022 the final was confirmed passed. The permit wording has to match the installed work — see why solar inspections fail.
How it ran
| May 2022 | New layout for fire-access clearances; system installed |
|---|---|
| August 2022 | LADBS asks for a load calculation for the de-rate |
| Early September 2022 | Load calculation: the main must stay at 200 A |
| 8 September 2022 | Plans with a 225 A panel approved |
| 19 September 2022 | Service panel replaced |
| 30 September 2022 | First final: correction to the permit wording |
| 18 October 2022 | Second final: work in order, permits to be reissued |
| 23 November 2022 | Final confirmed passed |
The work was in order by mid-October; the permits caught up in November.
What we did
- Flagged the missing fire-access clearances and installed to a new layout.
- Prepared the load calculation LADBS asked for.
- Replaced the service panel with a 225 A panel keeping the 200 A main.
- Set the new panel into the stucco wall and patched around it.
- Met the inspector at both finals.
System specifications
| System size | 12.8 kW DC / 11.4 kW AC |
|---|---|
| Inverter | SolarEdge HD-Wave, rapid shutdown |
| Roof | Flat concrete tile |
| Service panel | Siemens meter-main, 225 A busbar, 200 A main |
| Load calculation | Main breaker to stay at 200 A or more |
| Utility / AHJ | LADWP / LADBS |
Is your project like this one?
- You were told your main breaker could be de-rated for solar.
- You are planning a system of around twelve kilowatts.
- You have a flat concrete tile roof.
- You want to know what a load calculation decides.
- Your service panel may need replacing before solar.
Cali Energy in Mission Hills
Mission Hills is a neighborhood inside the City of Los Angeles: permits run through LADBS, interconnection through LADWP.
Mission Hills is a neighborhood inside the City of Los Angeles, next to the separate City of San Fernando. Its permits come from LADBS and its grid connection from LADWP, and LADBS checks how a solar system joins the house's service panel before it signs off.
- License and classifications: CSLB #1032379
- Official reference for this process: LADBS — inspections
- Official reference for this process: SolarEdge — support resources
Frequently asked questions
Why was the main breaker not de-rated on this Mission Hills system?
Because the load calculation showed the house needed at least 200 amps. De-rating would have swapped the 200-amp main breaker for a 175-amp one, to leave room on the panel's busbar for the solar breaker. With the main fixed at 200 amps, the room came from a new panel with a larger, 225-amp busbar, keeping a 200-amp main.
What was the correction at the first final?
Paperwork. A supplemental permit from the spring still described de-rating the panel to 175 amps, and a plan sheet still showed a 175-amp breaker. Since a 225-amp panel had gone in, the de-rate was not needed, so the permit had to be corrected or closed. On the same notice the inspector cleared the stucco lath to be covered and approved the equipment on the roof.
How long did it take from install to final?
About six and a half months, and most of it went to the panel question. The system was installed in May 2022, LADBS asked for the load calculation in August, the panel was replaced on 19 September, and the finals were on 30 September and 18 October. The permits were reissued in mid-November, and the final was confirmed passed on 23 November.
Does Cali Energy replace service panels for solar in Mission Hills?
Yes. On this Mission Hills project Cali Energy prepared the load calculation, replaced the service panel with a 225-amp panel keeping the 200-amp main, set it into the stucco wall and met the inspector at both finals. Permits here run through LADBS and interconnection through LADWP. License CSLB #1032379.
What this would look like on your roof
Planning solar in Mission Hills? Tell us your utility, your roof and what your bill looks like now, and we will model what a system like this would do on your house before you commit to anything.
Or call +1 (323) 844-7777 · Cali Energy, Northridge · CSLB #1032379 (B, C-10, C-39) — design, permits, install and electrical under one licensed contractor.
Related
Updated October 2026.