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Title 30, Mineral Lands and MiningRelease 119-110

§867 Grounding of Equipment

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

Last updated Sep 22, 2026|Official source

Summary

Require metal coverings, armor, conduits, and equipment frames that could become live to be continuous and grounded in ways the Secretary’s authorized representative approves. Frames of off-track direct-current machines and their detached parts must be grounded or kept at equally safe voltages. Stationary high-voltage equipment fed from ungrounded delta systems must also have grounded frames. Other equally protective methods may be allowed. High-voltage lines, surface or underground, must be shut off and grounded before work. Repairs to energized surface lines are allowed only if a qualified person follows safety procedures the Secretary sets before this part takes effect; the mine operator must provide, test, and maintain protective devices. Underground power circuits must be shut off on idle days and idle shifts, but rectifiers and transformers may remain energized.

Full Legal Text

Title 30, §867

Mineral Lands and Mining, Source: USLM XML via OLRC

(a)Metallic enclosed power conductors; metallic frames and other equipment; methods
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)Frames of offtrack direct current machines; enclosures of related detached components
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)Stationary high-voltage equipment powered by underground delta systems
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)Repairs of high-voltage lines; exceptions
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)Deenergizing of underground power circuits on idle days; exceptions
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 30, Mineral Lands and Mining

Last Updated

Sep 22, 2026

Release point: 119-110