# IEEE C57.12.40 — Which OSHA-recognized labs (NRTLs) can certify to a given test standard

For IEEE C57.12.40, standard title is Three Phase Secondary Network Transformers, Subway and Vault Types (Liquid Immersed); 2500 kVA and Smaller; status is listed as appropriate, recorded from its source on 2026-08-10.

- **Test standard:** IEEE C57.12.40 _(verified: appears in the quote below)_
- **Standard title:** Three Phase Secondary Network Transformers, Subway and Vault Types (Liquid Immersed); 2500 kVA and Smaller _(verified: appears in the quote below)_
- **Status:** listed as appropriate _(our reading, not quoted from the source)_

## What the source says

> IEEE C57.12.40 | Three Phase Secondary Network Transformers, Subway and Vault Types (Liquid Immersed); 2500 kVA and Smaller |

## Source

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

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/).