128. Signalling .-Where electrical signalling is used-
(a)adequate precautions shall be taken to prevent signal and telephone wires coming into contact with other cables and apparatus;(b)the voltage used in any one circuit shall not exceed 30 volts; and(c)contact-makers shall be so constructed as to prevent the accidental closing of the circuit;(d)[ bare conductors, where used shall be installed in suitable insulators.]
