“ A COMPLETE SHUT OUT.”

Star (Christchurch), Issue 17220, 11 December 1923, Page 7

“ A COMPLETE SHUT OUT.”

BEST INSULATORS NEEDED. “It was a complete shut-out,” said an electrical engineer this morning, referring to the break-down on tlie Lake Coleridge transmission lines. “It is two years sine© we have had such a stoppage, and I think it hard luck for the Department and for the city that both lines should have failed on the same night. It is certainly a coincidence that the trouble should have occurred at a time when power was being switched through to Timaru, but it is nothing more than a coincidence From what I can learn, the extension, would not be responsible for any ‘ surge.’

“ A ery likely it will be found that the long spell of dry weather, followed by intense humidity, caused tho breakdowns. The dry weather would puncture tho insulators, making holes in the glazed porcelain, and when the rain came it got through down into the stem. Or the drought may have expanded tho insulators and tlie sudden change in the weather contracted them with adverse results. Some authorities believe that dust may have gathered on the insulators and that the rain turned the dust into mud, causing flash-outs. Whatever the cause, the lesson is plain. The Department should go in for the best insulators that money can buy. In fact, cost should not be considered at all.” THE SUSPENSION SYSTEM.

Most of tho high tension schemes in the world use suspension insulators,” said another engineer. “That is the type we should have on the Lake Coleridge transmission lines. It would be necessary to have two poles together at each point or to have towers, and the expense would be heavy, but initial expense is a minor item. AYe must consider the inconvenience and loss that results from breakdowns of this kind. It pays to get the best.

j ” AA’hen the transmission lines were erected, tlie insulators were guaranteed to last six years. Most of them, I understand, have been replaced fairly i recently with better quality insulators, J but some have not. It would interest- ' iug to know which insulators could not stand the strain, the latest expensive insulators or the original insulators put in nine years age. On the strength of that information the Department should know what to instal in future. The City Couricil will also have some thing to go* on when it comes to deal with the AA'aimakariri scheme. The trouble is that consumers in the city have to bear the expenso of these lessons. ‘ ‘ There is another The Department have run a third line from Lake Coleridge to the city, but until an additional building is completed at j Addington that third lino is not really j a separate unit liko the other two lines. AYe should have that third line complete. Then the city would be safe from power interruptions.

It would bo a remarkable coincidence if the insulators on three lines broke down simultaneously. However, I am not blaming anyone. AV© have had a good spell for two years, and as time goes on, provided the best material is used, ive will have fewer interruptions.”