Solar Contractor License Requirements in California: C-46, C-10, and What You Need

California contractor licensing for solar work has some nuances that trip up contractors — particularly around which license allows what work, and when a C-46 is sufficient vs. when a C-10 is required. This guide covers the licensing requirements for solar, electrical, and HVAC work in California.

The C-46 Solar Contractor license

California's C-46 license is a specialty contractor classification specifically for solar energy system installation. A C-46 license holder can:

• Install solar photovoltaic (PV) systems on residential and commercial properties
• Perform the electrical work directly related to and incidental to the solar installation — including wiring from modules to inverter to the point of connection at the electrical panel
• Install solar thermal systems

The key limitation of a C-46: it covers solar-incidental electrical work only. If the solar installation requires a panel upgrade, new subpanel, or electrical work beyond the solar system itself, that work requires a C-10 (Electrical Contractor) license. A C-46 contractor cannot perform panel upgrades under their C-46 license alone.

The C-10 Electrical Contractor license

The C-10 license covers all electrical contracting work in California, including solar installations. A C-10 contractor can:

• Install solar PV systems and all associated electrical work
• Perform panel replacements and service upgrades
• Install EV chargers
• Install battery storage systems and associated electrical work
• Perform all electrical work regardless of whether it's solar-related

Many high-volume solar contractors maintain both a C-46 and a C-10 (either through the same individual or by having licensed C-10 employees on staff) to handle the full range of solar project types without subcontracting electrical work.

When you need a C-10 on a solar project

The most common scenarios where a C-46 alone is insufficient:

• Solar installation requires a panel upgrade from 100A to 200A
• Solar + EV charger combination where EV charger is on a new dedicated circuit
• Solar + battery storage where storage requires new subpanel or additional circuits
• Any solar project at a building department that requires C-10 licensing on the permit application (some jurisdictions specifically require C-10 on solar permits)

HVAC licensing: C-20

HVAC work in California requires a C-20 (Warm-Air Heating, Ventilating, and Air-Conditioning) license. C-20 contractors can install, repair, and replace HVAC systems, ductwork, and associated equipment. HVAC work that includes new electrical circuits (like heat pump installations) requires coordination with a C-10 licensed contractor for the electrical portion, unless the C-20 contractor also holds a C-10 or B license.

Plumbing licensing: C-36

Plumbing work requires a C-36 (Plumbing) license. Water heater replacements, repiping, gas line work, and other plumbing permits require the C-36 license number on the application.

The B General Building Contractor license

A B (General Building Contractor) license allows contractors to take on projects where two or more unrelated trades are involved, with the requirement that licensed subcontractors perform specialty work. Some solar companies operate under a B license and subcontract C-10 and C-46 work. This is legal and common, but each subcontractor must carry their appropriate specialty license, and their license numbers must appear on permits where required.