What Is UL Listing?
UL (Underwriters Laboratories) listing is a certification indicating that a product has been tested and meets specific safety standards. For cable assemblies and power supplies, this typically means compliance with UL standards such as UL 62 (flexible cords), UL 758 (appliance wiring material), or UL 60950/62368 (IT and AV equipment).
While UL listing is not legally mandatory in the US, it is effectively required by most buyers, retailers, and authorities having jurisdiction (AHJs). Building codes and insurance requirements frequently reference UL standards.
The Application Process
The process begins with a project enquiry to UL, where you describe your product, intended markets, and applicable standards. UL assigns a project handler who reviews your documentation and identifies which tests are needed.
You then submit product samples and technical documentation (drawings, BOMs, material data sheets). UL testing typically takes 4–8 weeks depending on product complexity and lab scheduling.
Factory Inspections
Once your product passes testing, UL conducts an initial production inspection (IPI) at your manufacturing facility. This verifies that production processes match the tested configuration.
After listing is granted, UL conducts unannounced follow-up inspections — typically quarterly — to ensure ongoing compliance. The factory must maintain records of materials used, production tests performed, and any product changes.
Maintaining Your Listing
Any change to materials, construction, or suppliers must be reported to UL before implementation. This includes changing wire suppliers, modifying connector types, or altering assembly processes.
UL charges annual maintenance fees in addition to follow-up inspection costs. Budget for these ongoing costs when planning your product programme — they are a cost of doing business in North America.