(9)Where telephones or electrical signals are provided,-(a)adequate precautions shall be taken to prevent signal and telephone wires coming into contact with other cables and electrical apparatus;(b)signal wires shall be supported on insulators, and shall not be energised at more than thirty volts;(c)contact makers shall be so constructed as to prevent accidental closing of the circuit; and(d)in every gassy seam of the second or third degree, all signaling or telephonic communication circuits shall be constructed, installed, protected, operated and maintained in such a manner as to be intrinsically safe.
