For MOVs and SPDs the two marks certify different things — complete end products versus components. Here is how to tell them apart, and how to verify any supplier's UL claim yourself in UL Product iQ.
UL Listed applies to complete end products evaluated for their intended installation. UL Recognized applies to components that are evaluated for use inside an end product, under stated Conditions of Acceptability. A metal oxide varistor (MOV) is a component, so the correct UL route for a varistor is component recognition under UL 1449 — not listing. If a supplier advertises a “UL Listed” varistor, that wording alone is a reason to ask for the file number and check what the record actually says.
Listing is UL's evaluation of a complete product for its intended use and installation. A listed product is tested as a whole device — enclosure, connections, protective functions and ratings together — and may carry the UL Listing mark when it is installed as evaluated.
A finished surge protective device is an end product: panel-mount and DIN-rail SPDs are listed devices under UL 1449 (for example Type 1 and Type 2 SPDs), because the safety case — enclosure, disconnection, fusing, follow current and ratings — only exists at the level of the complete device.
Component Recognition is UL's evaluation of a component that is intended to be built into an end product. The component is evaluated under stated Conditions of Acceptability — ratings and application limits the end-product designer must respect — and it is taken into account when the finished end product is certified.
For surge-protective components, recognition is granted under UL 1449 as Type 5 component recognition, and the public records appear in UL Product iQ under category VZCA2 (United States) and VZCA8 (Canada). Recognized components carry the UL Recognized Component mark — a different mark from the Listing mark, for a different job.
An MOV has no standalone installation: it is soldered or assembled into an SPD, and the finished device provides the enclosure, the disconnector and the thermal protection that complete the safety case. UL therefore recognizes the MOV as a component and lists the finished SPD. When a varistor datasheet says “UL Listed”, it is mixing the two categories — what the supplier may actually hold (if anything) is a Recognition record. The wording matters because a compliance review will check the record, not the datasheet: ask for the file number and verify the record type, the holder and the exact models covered.
Flyboat MOVs are UL 1449 Recognized under File E335803 (UL Product iQ categories VZCA2 / VZCA8, Type 5 component recognition), held by Guiyang High-Tech Yige Electronic Co., Ltd. The record covers 31 model grades of the 34S series — varistor voltages from 82 V to 1,800 V — plus the 20S, 22S, 27L and 30S series and DC-rated variants; the full coverage table is on our Certifications page. We describe our MOVs as Recognized because that is what they are, and we state openly which series are not covered. Finished SPDs built with our MOVs are certified as end products under the customer's program.
Sourcing MOVs for an SPD program, and your compliance team has questions about recognition? Contact our North American team — Thomas Dong, [email protected], +1 267-809-2765.
