UL 991 — Tests for Safety-Related Controls Employing Solid-State Devices
Reference: UL 991 · Scheme: OSHA NRTL product safety. The 4 laboratories below appear in the Current list of Nationally Recognized Testing Laboratories for this standard. Retrieved July 2026; ranking criteria on the methodology page.
| # | Laboratory | Location | Cert / ID | Approved | Registry accreditations |
|---|---|---|---|---|---|
| 1 | UL LLC | Northbrook, Illinois, United States | — | — | 6 |
| 2 | SGS North America, Inc. | Suwanee, Georgia, United States | — | — | 3 |
| 3 | TUV Rheinland of North America Inc. | Pleasanton, California, United States | — | — | 2 |
| 4 | CSA Group Testing and Certification Inc. | Etobicoke, Ontario, Canada | — | — | 1 |
Facts reproduced from the linked registry as retrieved July 2026. No ratings, no reviews — see methodology.