100. Leakage on conduit system .-Where both the line and the return are placed within a conduit, the following conditions shall be fulfilled in the construction and maintenance of the system:-
(a)where the rails are used to form any part of the return, they shall be electrically connected (at distances not exceeding 30 metres apart), with the conduit by means of copper strips having a cross-sectional area of at least 0.40 sq. cm. or by other means of equal conductivity. Where the return is wholly insulated and contained within the conduit, the latter shall be connected with earth at the generating station or sub-station through an instrument suitable for the indication of any contact or partial contact of either the line or the return with the conduit; and(b)the leakage-current shall be ascertained daily, before or after the hours of running, when the line is fully charged; and if at any time it is found to exceed 0.6 ampere per km. of single tramway track, the transmission and use of energy shall be suspended unless the leakage is stopped within twenty-four hours.
