All uninsulated electrical return circuits must be of such current carrying capacity and so arranged that the difference of potential between any two points on the return will not exceed the maximum limit of 12 volts, and between any two points on the return 1,000 feet apart within one mile radius of the city hall will not exceed the limit of one volt, and between any two points on the return 700 feet apart outside of this one mile radius limit will not exceed the limit of one volt. In addition thereto, a proper return conductor system must be so installed and maintained as to protect all metallic work from electrolysis damage.
The return current amperage on pipes and cable sheaths must not be greater than 0.5 amperes per pound foot for caulked cast iron pipe, 0.8 amperes per pound foot for screwed wrought iron pipe, and 0.16 amperes per pound foot for standard lead or lead alloy sheaths of cables.
All persons operating street railroads must equip their uninsulated return current systems in the following manner:
(1) With insulated pilot wire circuits and voltmeters so that accurate chart records will be obtained daily showing the difference of potential between the negative bus bars in each station and at least four extreme limits on the return circuit in its corresponding feeding district.
(2) With recording ammeters, insulated cables and automatic reverse load and overload circuit breakers which will record and limit the maximum amperes drained from all the metallic work, except the regular return feeders, to less than ten percent of the total output of the station.
The said chart records must be so kept as to be always accessible to city officials.
Any person failing to comply with the provisions of this section shall be fined not less than $50.00 nor more than $200.00 for each offense. Each day's operation of such equipment contrary to said provisions shall constitute and be regarded as a separate and distinct offense. Provided, that the said section shall not be construed as modifying or extending any express provisions relating to the subject matter thereof contained in any contract ordinance under which such systems are operated.
(Prior code § 188-22)