Who can replace my solar inverter in California, and does it need a permit?

String inverter or microinverters, and who may swap them

A string inverter converts the power of a whole string of panels in one box. Microinverters sit under individual panels, which is why the model prices them per microinverter and a string inverter per unit. Ask the company which type your system has and which type the quote replaces, because the price table below carries a separate row for each.

CSLB's Solar Smart page lists A, B, C-10 Electrical and C-46 Solar as the classes that can legally install PV, and describes C-46 as covering work to install, modify, maintain and repair PV systems. The heating-only classes C-4, C-36 and C-53 aren't on that list. Look up the company's license number and class on CSLB's lookup before you sign.

String or micro: California inverter prices in the model

Our model puts a string inverter replacement at $1,400 to $3,775 per string inverter, installed. It begins with a single national range, widened 15 percent each side, and applies California's installer wage ratio of 1.09; the table also shows the microinverter row, priced per unit. Both are estimates and not quotes, neither adds a permit fee, and no federal credit comes off.

The ranges don't cover monitoring hardware, a battery tied to the inverter, a new electrical panel or roof access. Ask whether the price covers removing the old unit, the warranty on the new one and any utility paperwork.

Estimated range. Built from national published ranges (1 source), adjusted by California's solar installer wage ratio to the US (1.09, BLS May 2025), plus the city solar permit fee where the city publishes one. Not a quote. One California installer publishes its own quoted range (per watt and per battery), too few to build a range from; the others print blog averages, which we do not count. We have no California company price for this job, so the range is our national estimate alone. Full method. Prices as of Oct 23, 2026.

The CEC equipment lists and the model number on the quote

Listing on the California Energy Commission's solar equipment lists isn't a condition for installing an inverter in California, the CEC says, and some utilities and local governments use the lists, which are updated three times a month, in their applications. For PG&E, SCE and SDG&E, the joint Rule 21 instruction sheet dated 6/5/2025 verifies equipment through the CEC listing or the utility's own list. Through the CEC route, an inverter needs a "Y" under UL 1741 SB, 3rd Edition, and a "Y" or "Y*" for CSIP conformance. Get the model number in writing.

If the company says a new inverter will raise your output, that's a production claim, and Solar Smart says to get those in writing along with the warranty terms for the new unit.

Rule 21, review times and who tells the utility

Rule 21 is the CPUC tariff that sets interconnection, operating and metering requirements for generation connected to PG&E, SCE or SDG&E. LADWP and SMUD, as municipal utilities, run their own rules. PG&E says permission to operate typically takes 5 to 10 business days after it has the contractor's paperwork, up to 30. SCE says a simple solar-only request may get permission within 10 business days, and that paired storage or non-standard metering will need more time; SDG&E's October 2024 deck puts initial review at 15 business days.

Behind each utility's rules sits Rule 21's Material Modification. SCE's tariff sheet defines it as a change with "a material impact on cost or timing" of interconnection requests queued on the same date or later, or a change in the point of interconnection. Fees for a new request are on the interconnection and permits page.

PG&E's Form 79-1211 sorts an inverter swap by what goes in. A unit of the same make and model needs no worksheet. A like-for-like unit, which the form defines as "certified, same nameplate or smaller, same fault current or smaller", goes on the notification-only path if its output stays within the nameplate in your interconnection agreement and the operating mode doesn't change. On that path the system can come back on "without waiting for PG&E approval" once the worksheet has been in for at least 2 business days. Keep the filed copy.

Bigger inverters have a tier too. The form allows a larger nameplate by notification only when certified power controls limit real power output to the capacity in your agreement and the system stays at 100 kW or less; otherwise PG&E needs a new Interconnection Request. So does a battery added to a system that had none.

SCE and SDG&E word it differently. SCE's FAQ lets a qualified like-for-like replacement that keeps output within what SCE approved go by notice on Form 14-987, with no new application and no SCE approval. An increase of more than 10 percent of the original net output capacity, or 100 kW if that's less, needs a new application and SCE's approval. SDG&E's NEM application lists "changing inverters/turbines" as a modification to an existing agreement, and SDG&E lists Form 117-2300 as its worksheet, so ask the company which one it will file.

Papers to keep once the new inverter is in

Keep the new inverter's warranty and the invoice with your original contract and its cover-page disclosure. Customers on NEM 2.0 may stay on that tariff for 20 years from the date they interconnected, and NBT customers keep theirs for nine years, so keep the permission-to-operate letter from the original installation with them.

If an inverter fault turns out to be part of a wider problem, the solar repair page covers a diagnostic visit, and a battery tied to the inverter has its own rows on the battery page.

When an inverter problem can't wait

What to read before you call

1. Note the inverter's make, model and the exact message on its display or in the monitoring app.
2. Find the warranty papers and the original contract.
3. Check the exports line on your latest utility bill.

Does an inverter swap need a permit

San Diego's Information Bulletin 301 prices PV electrical permits by the first system or inverter: $275.80 for the inspection, a $154.20 plan check row where plan review applies, and a $12.16 mapping fee if applicable. Ask your building department whether a like-for-like swap needs an electrical permit, and ask the company who pulls it.

Whatever path the utility takes, PG&E's worksheet leaves approval from the local building department with the customer.

Ask for the company's contractor license number and look it up with your state's licensing board before you sign.

Questions people ask

Keep reading

Guides

• Utility interconnection timelines: what DTE, Consumers Energy, PG&E, SCE and SDG&E say
• Solar quotes: what to compare, and what to get in writing, before you sign
• Net metering, distributed generation and net billing: how each state credits the power you send out

Related services

• Solar repair
• System inspection
• Solar battery storage
• Solar panel installation

California licensing, code and permit facts · Report a wrong price or rule