(1) Where an uninsulated return is in proximity to any metallic pipe, structure or substance not belonging to the owner of the return, the owner of uninsulated return shall, if so required by the owner of such pipe, structure or substance, connect his return therewith at his own expense.
(2) Where the return is partly or entirely uninsulated, the owner shall, in the construction and maintenance of his system, adopt such means for reducing the difference produced by the current between the potential of the uninsulated return at any one point and the potential of the uninsulated return at any other point as to ensure that the difference of potential between the uninsulated return and any metallic pipe, structure or substance in the vicinity shall not exceed four volts where the return is relatively positive, or one and one-third volts where the return is relatively negative.
(3) The owner of any such pipe, structure or substance in respect of it require the owner of the uninsulated return at reasonable times and intervals to ascertain by test in his presence or in the presence of his representative, whether the condition specified in sub-regulation (2) is fulfilled, and, if such condition is found to be fulfilled, all reasonable expenses of, and incidental to, carrying out of the test shall be borne by the owner of the pipe, structure or substance.
(4) The potential of uninsulated return with respect to earth at any point shall not exceed 50 V under normal conditions.
(5) The petroleum sidings installation earth shall be connected to the uninsulated return to make it equipotential and pipelines in the vicinity of the track should be properly earthed.