Decision guide
Electrical (C-10) vs HVAC (C-20): Where the Scopes Divide
C-10 and C-20 overlap on nearly every mechanical project, which is exactly why the boundary matters. The equipment is mechanical; the power feeding it is electrical. Contract scope should say which side you are responsible for.
Electrical (C-10)
Oriented toward electrical systems and equipment: services, panels, feeders, branch circuits, and electrical devices.
HVAC (C-20)
Oriented toward warm-air heating, ventilating, and air-conditioning systems, including equipment, duct work, and refrigerant circuits.
Side-by-side criteria
| Criterion | Electrical (C-10) | HVAC (C-20) |
|---|---|---|
| Primary systems | Electrical services, panels, feeders, and branch circuits | Heating, cooling, ventilation equipment and duct systems |
| On a rooftop unit replacement | Typically the disconnect and circuit feeding the unit | Typically the unit, curb, duct connections, and refrigerant work |
| Controls and thermostats | Electrical supply and, depending on scope, some control wiring | System controls, thermostats, and commissioning |
| Refrigerant work | Generally outside scope | Generally within scope, subject to separate federal certification |
| Exam focus areas | Conductor sizing, overcurrent protection, grounding and bonding, wiring methods | Load concepts, duct sizing, airflow balancing, refrigerant and venting practices |
| Separate certification to check | California electrician certification for employees performing electrical work | Federal refrigerant handling certification |
| Common arrangement | Subcontract to the HVAC contractor or hold both classifications | Subcontract the electrical scope or hold both classifications |
Which one fits you
Lean toward Electrical (C-10) if
- Your work centers on services, panels, feeders, and branch circuits
- You troubleshoot and repair electrical systems as your core service
- Your documented experience is electrical installation and troubleshooting
- You want to bid electrical packages as the responsible contractor
Lean toward HVAC (C-20) if
- Your work centers on heating and cooling equipment and duct systems
- You perform refrigerant charging, startup, and commissioning
- Your documented experience is HVAC installation and balancing
- You want to bid mechanical packages as the responsible contractor
Classification scope is defined by CSLB. This comparison summarizes how the two classifications are commonly distinguished; confirm the controlling scope language with CSLB before bidding work.
Frequently asked questions
Do I need both C-10 and C-20 to change out an HVAC unit?
It depends on the scope you take. If you are responsible for both the equipment and the electrical supply work, you generally need the classification covering each part, or a licensed subcontractor for the other.
Who handles the thermostat and control wiring?
Control wiring can fall on either side depending on voltage and scope. Define it explicitly in the contract rather than relying on jobsite custom.
Is refrigerant certification part of the license?
No. Refrigerant handling is regulated separately from CSLB licensing. Confirm current federal requirements independently.
Where should I verify this before making a decision?
Use the official CSLB classification and applicant pages linked below. Classification scope, examination requirements, and fees change, so treat CSLB as the authority and this page as orientation.