Class Code 8390
Auto, Truck Or Van Conversion Or Customizing
Class Code 8390 covers businesses that convert or customize autos, trucks, and vans — from camper and ambulance upfits to mobility conversions and custom interiors. This classification matters because conversion work combines fabrication, electrical, welding and finishing tasks that create distinct loss exposures; the September 1, 2026 approved pure premium rate is $2.918 per $100 of payroll.
What Class Code 8390 Covers
This class applies to operations that permanently alter a vehicle's structure or systems rather than routine mechanical repair or retail auto sales. Typical covered work includes installing custom bodies, camper shells and slide-outs; upfitting commercial fleets with shelving, ladder racks or refrigeration units; installing wheelchair lifts, ramps and interior accessibility systems; fabricating and welding structural mounts and brackets; completing interior build-outs such as cabinetry, upholstery, electrical systems, lighting, plumbing for RVs, and spray painting or finishing. It also covers mobile on-site conversion crews who perform the customizing at customer locations. Routine maintenance, engine-only repairs, and vehicle sales are usually classified under different WCIRB codes, so accurate job descriptions and payroll allocation are critical.
Who It Applies To
- Independent conversion shops and van-upfitters (mobility, commercial, recreational)
- Specialty fabricators doing custom truck bodies, flatbeds, or service bodies
- Ambulance, utility, and fleet upfit businesses that install equipment and systems
- Mobile conversion crews that perform on-site installations at customer locations
- Upholsterers, electricians, welders, and carpenters employed by conversion shops
- RV and camper interior builders and refinishers
Common Job Duties
- Measuring, cutting, welding, and fabricating metal brackets, frames, and mounts
- Installing electrical systems, inverters, auxiliary batteries, lighting and controls
- Mounting and aligning wheelchair lifts, ramps, and hydraulic/pneumatic systems
- Carpentry and cabinetry installation for camper and recreational interiors
- Spray painting, sanding, surface preparation and clear-coat finishing
- Upholstery, trim work, and installation of interior panels and insulation
- Testing vehicle systems, making wiring connections, and road-testing modified vehicles
Common Injury Risks
Understanding the $2.918 Rate
The approved pure premium rate of $2.918 per $100 of payroll represents the expected cost of losses (medical + indemnity) for this class before insurer expenses and adjustments. To estimate the pure premium, multiply payroll by the rate and divide by 100 (for example, $100,000 payroll × $2.918 / 100 = $2,918 expected loss cost). The final premium an employer pays will also include insurer expense loads, policy endorsements, experience modification (X-mod), payroll audits, chosen deductibles, and any credits for safety programs or group-rating arrangements.
Cal/OSHA Compliance Requirements
Conversion shops must follow Cal/OSHA (Title 8) rules that commonly apply to this work: welding/brazing and hot work controls, respiratory protection and ventilation for spray painting and sanding, electrical safety orders for low-voltage vehicle systems, fall protection when working at heights on vehicle roofs, machine guarding for metalworking equipment, and lockout/tagout for powered equipment. Employers must maintain written programs required by Cal/OSHA including an Injury and Illness Prevention Program (IIPP), hazard communication (for paints/solvents), respiratory protection program, and hot-work permits where applicable.
How Key HR Helps Employers Under Class Code 8390
A PEO like Key HR helps employers in Class 8390 by ensuring payroll is properly classified, managing workers' comp claims to control indemnity and medical costs, and implementing loss-control programs tailored to conversion shops (welding safety, respirator fit-testing, confined-space procedures for enclosed vehicle interiors). Key HR can coordinate Cal/OSHA-compliant written programs, provide training (hot work, electrical safety, fall protection), pursue favorable experience modification outcomes, and bundle HR and payroll services to reduce administrative errors that drive premium surprises.
Get a QuoteFrequently Asked Questions
Does Class 8390 cover mobile upfits performed at customer sites?
Yes. Mobile conversion crews performing permanent alterations or installations at customer locations generally fall under Class 8390, provided the work modifies the vehicle rather than only performing routine repairs. Accurate payroll tracking of mobile versus repair-only activity is important for correct classification.
If my shop also does engine repairs and routine maintenance, do those employees belong in 8390?
No. Employees primarily doing engine repair, routine mechanical service or general vehicle maintenance are typically classified under different WCIRB codes (e.g., mechanics/repair shop codes). You should segregate payroll by job type to ensure correct classification and premium allocation.
What steps can reduce my workers' comp premium for conversion work?
Implementing and documenting targeted controls—welding hot-work controls, local exhaust for paint booths, respiratory and hearing programs, fall protection, machine guarding, and a return-to-work plan—reduces claim frequency and severity. Partnering with a PEO for claims management, safety training, and accurate payroll classification can also lower your experience modification and premium over time.
Quick Facts
- Class Code
- 8390
- Classification
- Auto, Truck Or Van Conversion Or Customizing
- Pure Premium Rate
- $2.918 / $100 payroll
- Effective Date
- September 1, 2026
- Source
- WCIRB Approved Filing
Manage Workers' Comp Through a PEO
Key HR provides pay-as-you-go workers' comp for California employers — no large deposits, no audits, better rates.
Get a Quoteor call (800) 922-4133Ready to Simplify Workers' Comp for Class Code 8390?
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