30 CFR § 77.906 - Trailing cables supplying power to low-voltage mobile equipment; ground wires and ground check wires.

---
identifier: "/us/cfr/t30/s77.906"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "30 CFR § 77.906 - Trailing cables supplying power to low-voltage mobile equipment; ground wires and ground check wires."
title_number: 30
title_name: "Mineral Resources"
section_number: "77.906"
section_name: "Trailing cables supplying power to low-voltage mobile equipment; ground wires and ground check wires."
chapter_name: "MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR"
subchapter_number: "O"
subchapter_name: "COAL MINE SAFETY AND HEALTH"
part_number: "77"
part_name: "MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "30 U.S.C. 811."
regulatory_source: "36 FR 9364, May 22, 1971, unless otherwise noted."
cfr_part: "77"
---


# 77.906 Trailing cables supplying power to low-voltage mobile equipment; ground wires and ground check wires.

On and after September 30, 1971, all trailing cables supplying power to portable or mobile equipment from low-voltage three-phase resistance grounded power systems shall contain one or more ground conductors having a cross-sectional area of not less than one-half the power conductor. Such trailing cables shall include an insulated conductor for the ground continuity check circuit except where a no less effective device has been approved by the Secretary to assure continuity. Splices made in low-voltage trailing cables shall provide continuity of all components.