# UL 511 — Which OSHA-recognized labs (NRTLs) can certify to a given test standard

For UL 511, standard title is Porcelain Electrical Cleats, Knobs, and Tubes; status is no longer recognized, recorded from its source on 2026-08-10.

- **Test standard:** UL 511 _(verified: appears in the quote below)_
- **Standard title:** Porcelain Electrical Cleats, Knobs, and Tubes. _(verified: appears in the quote below)_
- **Status:** no longer recognized _(our reading, not quoted from the source)_

## What the source says

> UL 511 | Porcelain Electrical Cleats, Knobs, and Tubes. |

## Source

- https://www.osha.gov/nationally-recognized-testing-laboratory-program/standards-no-longer-recognized

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/).