Can the marking on a wire be used as evidence of compliance with VW-1 rating requirements?
More specifically you asked: when demonstrating compliance with 62368 wire flammability by way of the VW-1 equivalence concession, if a manufacturer has a file listing for AWM Style no. 20276 (which conforms to UL 758 which itself states a number of flammability tests which can be applied) where is the evidence of *which* flammability test was used? Is it sufficient to rely upon the product marking? If a cable is marked "[File Number] [UL logo] AWM Style 20276 80C 30V VW-1" is that sufficient to state that it meets VW-1 (on the basis that UL controls such marking?) Or is there a further document or certificate that should be provided to show which flammability test was performed?
In response, we confirm that a VW-1 rating is acceptable based on a National Difference for USA / Canada (in Annex DVF (6.5.1)) with its reference to UL 2556. A reference to UL 2556 VW-1 also is in sub-cl. 6.5.1 of IEC 62368-1 ED3, which provides this option for wider use under IEC 62368-1, although the acceptance is at the discretion of an NCB.
For wires recognized by UL under AVLV2 category, the markings, including identification, ratings and UL Mark, provided on a spool (tag, reel or smallest unit container) are considered the evidence of formal compliance and UL Recognition. (Please see the AVLV2 Guide Information under UL Product iQ for more details - https://iq.ulprospector.com/en/profile?e=206308 .) The marking provided on the wire itself is for reference only and, alone, generally is not considered as direct evidence of UL Recognition during end product Follow-up Service.
Please note that there may be a benefit for your suppliers of wiring and wiring harnesses to get covered under one of UL’s traceability programs, like the UL Wiring Harness Program - https://www.ul.com/services/wiring-harness-traceability-program . Then you would be able to trace the certification and ratings of your components to the original certification markings associated with the spool, etc. (Over 3000 wiring harness suppliers currently are certified under the wiring harness program, so some of your suppliers may already be covered - https://iq.ulprospector.com/en/profile?e=212703 .)
For any additional support needed you are encouraged to contact UL, either via your local account executive or via https://62368-ul-solutions.com/contact-ul.html .