Last updated: August 31st, 2026
Which California contractor licenses can legally perform solar work?
The answer depends on what kind of solar system you’re working on.
California’s Contractors State License Board (CSLB) authorizes several contractor classifications to perform solar-related projects, but their scopes are not interchangeable.
Some classifications can perform photovoltaic electrical work, while others are limited to solar thermal or heating work associated with their existing classification.
So it is not accurate to say that every contractor classification authorized for some type of solar work can install any photovoltaic solar energy system.
Here is the current breakdown.
An A-General Engineering Contractor is authorized to perform active solar energy projects that require specialized engineering knowledge and skill.
This can include solar work when it falls within the broader General Engineering scope.
The A classification is not simply a universal specialty solar license; the solar work still needs to fit the type of engineering project the classification authorizes.
A B-General Building Contractor may perform qualifying active solar energy projects in connection with a structure as defined by California Business and Professions Code section 7057.
CSLB explains that an active solar energy system constitutes the use of at least two unrelated building trades or crafts for purposes of the B-General scope.
This makes B-General one of the classifications that may install qualifying solar systems as part of work within the Class B scope.
For more information about B-General licensing, see our California B-General Building Contractor Exam Guide.
The C-10 Electrical Contractor classification is one of the key licenses for photovoltaic solar installations.
CSLB authorizes C-10 contractors to perform solar projects that:
Generate electrical energy
Transmit electrical energy
Transform electrical energy
Utilize electrical energy
That makes the C-10 classification appropriate for photovoltaic solar work involving electrical generation and related electrical systems within the C-10 scope.
If you’re pursuing this classification, read our California C-10 License Requirements Guide.
The C-46 Solar Contractor classification is the California specialty classification specifically dedicated to solar systems.
A C-46 contractor may:
Install solar energy systems
Modify solar energy systems
Maintain solar energy systems
Repair solar energy systems
The classification covers both:
Thermal solar energy systems
Photovoltaic solar energy systems
However, a C-46 contractor may not perform unrelated building or construction trades simply because a solar system is part of the project.
Other trades, crafts, or construction skills may be performed only when they are required to install the thermal or photovoltaic solar energy system.
You can review the official CSLB C-46 Solar Contractor classification for the current scope.
If you’re preparing for this classification, see our C-46 Solar Contractor License Exam Preparation resources.
The C-4 classification does not provide unrestricted authority to install photovoltaic solar systems.
Its solar authority is specifically tied to solar heating equipment associated with the systems authorized by the C-4 classification.
In other words, C-4 contractors can perform qualifying solar thermal/heating work when it falls within their Boiler, Hot-Water Heating and Steam Fitting scope.
Do not interpret C-4’s inclusion on CSLB’s solar list as permission to perform general photovoltaic electrical installations.
The C-36 Plumbing Contractor classification also has solar authority, but it is limited by its plumbing scope.
CSLB authorizes C-36 contractors to perform projects using solar equipment to heat water or fluids to a suitable temperature.
This is solar thermal work.
It does not mean a C-36 license by itself authorizes unrestricted photovoltaic electrical installation.
For a PV system involving electrical generation, the contractor needs to look to a classification whose scope actually includes that electrical work, such as C-10 or C-46, depending on the project.
A C-53 Swimming Pool Contractor may install solar heating as part of swimming pool projects.
Again, this is a scope-specific solar authorization.
C-53 should not be presented as a general photovoltaic solar installation license.
The authority is tied to solar heating within swimming pool work covered by the C-53 classification.
CSLB also recognizes C-61/D-35 Pool and Spa Maintenance contractors for a narrower type of solar work.
D-35 contractors may repair existing solar systems that heat swimming pools.
That is much more limited than the C-53 authority to install solar heating as part of pool projects and far narrower than a C-46 or C-10 photovoltaic scope.
For photovoltaic systems, the classifications you should primarily be looking at are:
C-46 expressly covers photovoltaic and thermal solar energy systems.
C-10 covers solar work involving generation, transmission, transformation, or utilization of electrical energy.
B-General may perform qualifying active solar energy projects associated with a structure when the work falls within the Class B scope.
A-General may perform active solar energy projects requiring specialized engineering when the work falls within the General Engineering scope.
Those classifications should not be confused with C-4, C-36, or C-53, whose solar authority is specifically tied to heating or thermal work within their respective trades.
Solar heating equipment associated with Boiler, Hot-Water Heating and Steam Fitting systems.
Solar equipment used to heat water or other fluids within the Plumbing scope.
Solar heating installed as part of a swimming pool project.
Repair of existing solar systems used to heat pools.
These classifications should not be marketed as if they all authorize complete photovoltaic installations.
The fact that CSLB lists a contractor classification as authorized to perform solar projects does not mean that contractor can perform every type of solar work.
Each contractor must remain within the legal scope of their classification.
For example:
A C-36 Plumbing contractor may work on a qualifying solar hot-water system.
A C-53 Swimming Pool contractor may install solar pool heating.
A C-10 Electrical contractor may perform qualifying photovoltaic electrical work.
A C-46 Solar contractor may perform both qualifying thermal and photovoltaic solar work.
Those are different scopes.
Before bidding or contracting for a solar project, determine:
What type of solar system is being installed?
Does the project involve photovoltaic electricity, thermal heating, or both?
Which contractor classification covers the specific work?
Will additional properly licensed specialty contractors be needed?
No.
Some classifications are authorized only for particular types of solar heating or thermal work within their existing trade scope.
C-4, C-36, and C-53 should not be treated as unrestricted photovoltaic classifications.
Yes.
C-10 Electrical contractors are authorized to perform solar work involving the generation, transmission, transformation, or utilization of electrical energy within the classification.
Yes.
The C-46 Solar Contractor classification expressly includes both thermal and photovoltaic solar energy systems.
A C-36 Plumbing contractor can perform qualifying projects involving solar equipment used to heat water or fluids.
That does not give the C-36 contractor unrestricted authority to install photovoltaic electrical systems.
A C-53 contractor may install solar heating in swimming pool projects.
That authority is tied specifically to pool solar-heating work.
The C-4 classification’s solar authority is tied to solar heating equipment associated with systems authorized by the C-4 classification.
It should not be treated as a general photovoltaic license.
A C-61/D-35 Pool and Spa Maintenance contractor may repair existing solar systems that heat pools.
California authorizes several contractor classifications to perform some type of solar work, but their authority depends on the scope of the individual classification.
The most important distinction is between photovoltaic and thermal work.
For photovoltaic solar projects, look primarily to classifications such as:
A – General Engineering
B – General Building
C-10 – Electrical
C-46 – Solar
For solar thermal or heating work, additional classifications may have authority within their specific scopes:
C-4 – Boiler, Hot-Water Heating and Steam Fitting
C-36 – Plumbing
C-53 – Swimming Pool
C-61/D-35 – Pool and Spa Maintenance, for repair of existing pool solar-heating systems
The takeaway is simple:
Being authorized to perform some solar work does not mean a contractor can perform every type of solar project.
Always match the contractor’s license classification to the actual scope of the solar work being performed.
For the official current guidance, review CSLB’s Solar Smart resources and License Classification descriptions.
