30 C.F.R. § 77.513 Insulating mats at power switches.
Title 30 - Mineral Resources
Dry wooden platforms, insulating mats, or other electrically nonconductive material shall be kept in place at all switchboards and power-control switches where shock hazards exist. However, metal plates on which a person normally would stand and which are kept at the same potential as the grounded, metal, non-current-carrying parts of the power switches to be operated may be used.
Title 30: Mineral Resources
PART 77—MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES
Subpart F—Electrical Equipment—General
§ 77.513 Insulating mats at power switches.

