An installer in Sacramento has spent three years on solar crews and two more doing panel upgrades. They are ready for their own license, and they are stuck on a question that sounds simple: C-10 or C-46? Both can install solar. Only one of them can also wire the panel upgrade, the EV charger and the heat pump circuit that often come with it.
Here is the plain answer. Five California classifications are well placed for 2026 because state rules keep sending work their way: C-10 Electrical, B General Building, C-20 HVAC, C-36 Plumbing and C-46 Solar. The California Energy Commission’s energy code now pushes new homes toward heat pumps, electric-readiness, solar and battery storage. State law keeps opening the door to accessory dwelling units. And older housing keeps needing repair.
We are not going to rank them by pay or market size. Those numbers change by region and year, and we will not print one we cannot source. What follows is what drives the work in each classification, what the license lets you do, and where the scopes overlap, which is where the real decision usually sits.
The short version
- C-10 Electrical: the widest reach into electrification work, including solar.
- B General Building: whole projects, including ADUs and remodels, that use two or more unrelated trades.
- C-20 HVAC: heating, cooling and ventilation, including heat pumps for space and water heating.
- C-36 Plumbing: water, waste and gas piping in every building, new or old.
- C-46 Solar: solar systems, thermal and photovoltaic, and nothing outside them.
What is driving the work
The energy code
California’s building energy code is updated on a cycle. The California Energy Commission says the 2025 Energy Code expands the use of heat pumps in newly built homes, encourages electric-readiness and strengthens ventilation standards. It applies to buildings whose permit applications are filed on or after January 1, 2026. The 2022 code before it expanded solar photovoltaic and battery storage standards and set electric-ready requirements for new homes.
Each of those touches a different license. Heat pumps are HVAC work. Electric-ready circuits, panels and batteries are electrical work. Solar can be several.
Accessory dwelling units
The state Department of Housing and Community Development describes ADUs and junior ADUs as an option for adding much-needed housing, and it publishes a handbook and enforces local ADU rules. An ADU is a small building project with foundation, framing, plumbing, electrical and finishes. That is general building work.
Older buildings
Much of California’s housing was built decades ago. Old supply pipe, undersized electrical service and tired heating systems do not fix themselves. Repair and replacement work keeps going whatever the new-construction market is doing.
1. C-10 Electrical
What the license covers: CSLB’s Description of Classifications says a C-10 places, installs, erects or connects electrical wires, fixtures, appliances, raceways, conduits and solar photovoltaic cells, anything that generates, transmits, transforms or uses electrical energy.
Why it fits 2026: panel and service upgrades, EV chargers, heat pump circuits, battery storage and solar all need an electrician. Electric-ready requirements in new homes add to that.
Fits you if: you have journeyman-level electrical experience and want the broadest scope in electrification.
Not the best fit if: your experience is solar installation only, without general electrical work to document.
See our C-10 Electrical exam prep.
2. B General Building
What the license covers: work on a structure that uses at least two unrelated building trades or crafts. That describes most remodels, additions and ADUs.
Why it fits 2026: ADUs and remodels need someone to run the whole job. CSLB’s guide also notes that a B contractor can perform active solar energy projects, because a solar system uses two unrelated trades.
Fits you if: you have run or supervised whole projects across trades.
Not the best fit if: you want to take single-trade jobs. CSLB’s guide says a B contractor cannot take a prime contract for a project involving trades other than framing or carpentry unless it requires at least two unrelated trades, or the contractor holds that trade’s license or subcontracts it.
3. C-20 HVAC
What the license covers: warm-air heating, ventilating and air-conditioning systems, including water heating heat pumps, the ducts, registers and controls, and systems that use solar energy.
Why it fits 2026: the energy code’s push toward heat pumps and stronger ventilation lands squarely here. Replacing older gas furnaces and air conditioners in existing homes keeps the service side busy.
Fits you if: you have installed and serviced heating and cooling systems.
Not the best fit if: your work is mostly refrigeration for commercial equipment. That is a separate classification.
4. C-36 Plumbing
What the license covers: safe water supply and the disposal of fluid waste in all structures, plus gas piping and gas appliance connections, among other listed work.
Why it fits 2026: every new building and every ADU needs plumbing. Older homes need repiping, sewer work and water heater replacement. A C-36 can also do solar water heating, according to CSLB’s guide.
Fits you if: you have journeyman-level plumbing experience, including gas.
Not the best fit if: your experience is limited to one narrow part of plumbing, like drain cleaning only.
5. C-46 Solar
What the license covers: installing, modifying, maintaining and repairing thermal and photovoltaic solar energy systems.
The limit: CSLB’s guide says a C-46 shall not do other building trades except when needed to install a solar system. A solar-only license is a solar-only business.
Fits you if: your experience is mainly solar and you plan to stay in solar.
Not the best fit if: you also want to do panel upgrades, EV chargers or other electrical work that is not part of a solar system. That points to the C-10.
See our C-46 Solar exam prep.
Where the scopes overlap
Solar is the clearest example. CSLB’s guide lists who may do solar work:
- C-10: any solar project that generates, transmits, transforms or uses electrical energy.
- C-46: thermal and photovoltaic solar systems, and only what is needed to install them.
- B: active solar projects, as two unrelated trades.
- C-36: solar equipment that heats water or fluids.
- C-20: heating, ventilating and air-conditioning systems that use solar energy.
So the choice is less about which license allows solar and more about what else you want to do. Our guide to choosing the right CSLB classification walks through that decision for any trade.
What every one of them requires
Whichever you choose, the path has the same shape. CSLB checks your experience, then you take two exams through PSI: the trade exam for your classification and the Law and Business exam. CSLB’s exam FAQ says you get 3-1/2 hours for each.
The trade exam tests what you already know from the field. The Law and Business exam tests things most tradespeople have never had to learn: contracts, liens, employment rules, licensing law. Plan your study time accordingly.
Questions candidates ask
Can I hold more than one classification?
Yes. Many contractors add a classification later. Each one has its own experience requirement, so check CSLB’s rules for adding a classification before you apply.
Is C-46 easier to get than C-10?
It is a different scope, not an easier version. Choose based on the work you want to do and the experience you can document.
Which one pays best?
We do not publish pay figures. They vary too much by region, business model and year to be useful as a single number.
Next step
Pick your classification and start with the exam that matches it on our California exam prep page. Every course includes the study guide and practice exams for that trade.