UL 551
For UL 551, standard title is Transformer-Type Arc-Welding Machines; status is listed as appropriate, recorded from its source on 2026-08-10.
- Test standard
- UL 551 verified
- Standard title
- Transformer-Type Arc-Welding Machines verified
- Status
- listed as appropriate our reading
Values marked our reading are our classification of what the source says — the source does not print them in those words. The quote below is the evidence for each one; judge it yourself.
What the source says
UL 551 | Transformer-Type Arc-Welding Machines |
— osha.gov, retrieved 2026-08-10
Source
- osha.govhttps://www.osha.gov/nationally-recognized-testing-laboratory-program/list-standards