# NEMA C37.51 — Which OSHA-recognized labs (NRTLs) can certify to a given test standard

For NEMA C37.51, standard title is Metal-Enclosed Low-Voltage AC Power Circuit-Breaker Switchgear Assemblies-Conformance Test Procedures; nrtl is UL; laboratory is UL LLC; status is currently recognized, recorded from its source on 2026-08-10.

- **Test standard:** NEMA C37.51 _(verified: appears in the quote below)_
- **Standard title:** Metal-Enclosed Low-Voltage AC Power Circuit-Breaker Switchgear Assemblies-Conformance Test Procedures _(verified: appears in the quote below)_
- **NRTL:** UL _(verified: appears in the quote below)_
- **Laboratory:** UL LLC _(verified: appears in the quote below)_
- **Status:** currently recognized _(our reading, not quoted from the source)_

## What the source says

> NEMA C37.51 | Metal-Enclosed Low-Voltage AC Power Circuit-Breaker Switchgear Assemblies-Conformance Test Procedures |

## Source

- https://www.osha.gov/nationally-recognized-testing-laboratory-program/ul

Last verified: 2026-08-10. Review by: 2026-11-08.
Part of [Which OSHA-recognized labs (NRTLs) can certify to a given test standard](https://referencesource.org/nrtl-recognized-test-standards/).