[=Trolley wires.=] All trolley wires shall be carried at least six inches outside of and parallel with the track rail on the side the trolley wire is located. When regular height is less than six feet six inches from top of rail, the lower side of trolley wire must not exceed six inches from the roof or cross-timber with hangers now in use, with hangers not to exceed twenty-five feet between centers, and the tension sufficient to keep all wires from sagging and to prevent trolley wheel from coming in contact with roof or cross-timbers. All new hangers hereafter installed shall not exceed five inches in depth from lower side of the trolley wire to the roof or cross-timbers. [=Wires crossing traveling ways.=] All trolley and positive feed wires crossing places where persons or animals are required to travel, shall be safely guarded or protected from such persons or animals coming in contact therewith. [=Wires opposite rooms and refuge holes.=] All trolley and positive feed wires shall be placed on opposite side of track from refuge holes or necks of rooms. [=Bare wires; when not to extend into working places.=] No trolley wire shall be extended into or maintained in any room while being used as a working place; no trolley or feed wire shall be extended into any entry beyond the outside corner of the last breakthrough. [=Switches and circuit-breakers.=] Switches or circuit-breakers shall be provided to control the current at the mine, and at all important points in the mine. [=Machine feed wires and insulators.=] All machine feed wires shall be placed as near the rib and roof or cross-timbers as practicable; the positive wire to be carried not to exceed three inches from the rib and roof or cross-timbers, measured at the insulators, which shall be so placed as to keep the wire at least six inches outside of the track rail on the side the wire is located. Insulators shall be placed not exceeding fifty feet apart, and all wires shall be carried so that same will be not less than six inches outside of the track rail at any point on the side the wire is located. All positive wires shall be carried on glass or porcelain insulators, or insulators equally efficient. All negative wires shall be carried on suitable fixtures, and when carried in same entry as the positive wire, shall be carried on the same side of the entry as the positive wire, and as close to it as practicable. When machine or feed wires are carried in same entry as trolley wire, they shall be placed on the same side as the trolley wire, between trolley wire and rib. Nothing in the foregoing shall require negative wires being carried in same entry with positive wire. [=Wires in shafts or slopes.=] When necessary to carry wires down shafts or slopes used as travelways, the wires must be thoroughly cased or protected, so that persons cannot be shocked therefrom.