ELECTROLYSIS HAS NOT AFFECTED ’PHONE SYSTEM

Star (Christchurch), Volume XLIV, Issue 142, 17 June 1931, Page 14

ELECTROLYSIS HAS NOT AFFECTED ’PHONE SYSTEM

Electrolysis as yet has not seriously affected the underground telephone system in Christchurch, not so much because stray currents have not been detected to any great extent, but the cause, where possible damage has been suspected, precautions have been taken to prevent it, states the report prepared by a special sub-committee of the Christchurch Public Utilities Committee. Periodic inspections and measurements are taken with a view to ascertaining what changes are taking place. Distinct leakage is known to exist in well defined areas, but an overhaul of the track system failed to reveal any inherent weakness in the plates and joints. Only bonding the cables to the rails saved them from corrosion. This method of protection has been adopted on more than one occasion, and the responsible authority is reminded 'from time to time that the cable system is carrying current that is of no practical value.

Extensive damage to water mains has been experienced by the City Council staff for many years, and renewals have been numerous. Bonding to the track rails has proved successful in several instances, and, although the results near the tramway powerhouse sheeted the trouble home to traction leakage, the cause of corrosion at more remote points is difficult of explanation. Despite the fact that the water mains provide the -only effective earth connection for the various systems in Christchurch, the City Engineer quotes the London Metropolitan Water Board as his authority for saying that this should not be done.