(a) Telephone lines, other than cables, where practicable shall be carried on insulators, installed on the opposite side from power or trolley wires, and where they cross power or trolley wires they shall be adequately insulated.

(b) Lightning arrestors shall be provided at the points where telephone circuits enter the mine, also at entrance of each surface building.

(c) Telephone cables permanently installed in power boreholes containing power cables shall be protected at top and bottom by insulating transformers.

(d) All proper precautions shall be taken to prevent electric signal and telephone wires from coming into contact with other electric conductors, whether insulated or not.

(e) Bare signal wires shall not carry more than twenty-four volts.

(f) Bells, wires, insulators, signal contacts and other apparatus used in connection with electric signalling underground, shall be of suitable design, of substantial and reliable construction, and erected in such a manner as to reduce the liability of failures or false signals to a minimum.

(g) In the face areas of a gassy mine, the potential used for signal purpose shall not exceed twelve volts. Electric signals and signal buttons shall be explosion proof. Bare wires shall not be used for signal circuits except on haulage roads.

(h) The potential on signal circuits confined to intake air and using insulated conductors may be greater than twelve volts, but shall not exceed one hundred twenty-five volts average. (This shall not apply to haulage block signal systems).