Title 30Mineral Lands and MiningRelease 119-73

§867 Grounding of equipment

Title 30 › Chapter CHAPTER 22— - MINE SAFETY AND HEALTH › Subchapter SUBCHAPTER III— - INTERIM MANDATORY SAFETY STANDARDS FOR UNDERGROUND COAL MINES › § 867

Last updated Apr 6, 2026|Official source

Summary

Ground metal covers, conduits, and equipment frames that could become energized. Use Secretary‑approved methods; other equally safe methods may be allowed. Ground frames of offtrack DC machines and of high‑voltage gear fed from ungrounded delta systems, or keep them at safe voltages. Deenergize and ground high‑voltage lines before work. Live surface‑line repairs are allowed only for qualified workers under strict Secretary rules; operators must provide, test, and maintain protective devices. Turn underground power circuits off on idle days and idle shifts, but rectifiers and transformers may stay on.

Full Legal Text

Title 30, §867

Mineral Lands and Mining — Source: USLM XML via OLRC

(a)All metallic sheaths, armors, and conduits enclosing power conductors shall be electrically continuous throughout and shall be grounded by methods approved by an authorized representative of the Secretary. Metallic frames, casings, and other enclosures of electric equipment that can become “alive” through failure of insulation or by contact with energized parts shall be grounded by methods approved by an authorized representative of the Secretary. Methods other than grounding which provide no less effective protection may be permitted by the Secretary or his authorized representative.
(b)The frames of all offtrack direct current machines and the enclosures of related detached components shall be effectively grounded, or otherwise maintained at no less safe voltages, by methods approved by an authorized representative of the Secretary.
(c)The frames of all stationary high-voltage equipment receiving power from ungrounded delta systems shall be grounded by methods approved by an authorized representative of the Secretary.
(d)High-voltage lines, both on the surface and underground, shall be deenergized and grounded before work is performed on them, except that repairs may be permitted, in the case of energized surface high-voltage lines, if such repairs are made by a qualified person in accordance with procedures and safeguards, including, but not limited to a requirement that the operator of such mine provide, test, and maintain protective devices in making such repairs, to be prescribed by the Secretary prior to the operative date of this subchapter.
(e)When not in use, power circuits underground shall be deenergized on idle days and idle shifts, except that rectifiers and transformers may remain energized.

Legislative History

Notes & Related Subsidiaries

Editorial Notes

References in Text

For the operative date of this subchapter, referred to in subsec. (d), see section 509 of Pub. L. 91–173, set out as an

Effective Date

note under section 801 of this title.

Statutory Notes and Related Subsidiaries

Effective Date

Section operative 90 days after Dec. 30, 1969, except to the extent an earlier date is specifically provided for in Pub. L. 91–173, see section 509 of Pub. L. 91–173, set out as a note under section 801 of this title.

Reference

Citations & Metadata

Citation

30 U.S.C. § 867

Title 30Mineral Lands and Mining

Last Updated

Apr 6, 2026

Release point: 119-73