STATE ELECTRICITY.

Auckland Star, Volume XLIII, Issue 102, 29 April 1912, Page 5

STATE ELECTRICITY.

THE COLERIDGE POWER-LINE. ALUMINIUM TO BE USED. (By Telegraph. - Own Correspondent.) WELLINGTON', this day. A further stage in the important work ! of completing the first of the State iiy- ] dro-el<*etric schemes in New Zealand lias j Wr, reached, tenders being now out for I the transmission line standards from | Lake Coleridge, and for the distributing wires in Christ, hurch and district. .'t has been decided by the Government ; Klectrieal Knginecr (Mr. Parry) to use : ferro-conorc-te poles for the. distributing ' mains, and .")()() are required to be delivered at Cl.ristchunli. They are to be 33ft long. The transmission line from the power station i> a. much more ex- , pensive item, no fewer than 1400 standards being required. Their material has been purposely left to the contractor to specify, the electrical engineer naming the stresses to be borne. Delivery is to be at Lyttclton. The transmission line itself will also be supplied by tender,' contractors being required to quote for . aluminium as an alternative to copper. ! In fact, it is higHy probable that alu- , minium will [,<• used for the main trans- : mission from power-house to city. This ' metal is not well known in New Zealand • as an electrical conductor, but it has ' been used in some of the largest trans- ! mission lines in Canada, and is often i found in Knjrlish installations. A copper ' line is three and one-third times heavier than tin aluminium line of the. same section. Aluminium being, however, only half as good an electrical conductor as i its older rival, the aluminium line has ' to be of twice the section of a copper one for the same efficiency. Even then the newer metal gains considerably in the. matter of the weight which has to be carried by the standards, while as its cost is about the same as copper, and it , is bought by weight, here again alu- \ minium scores. It is estimated that an aluminium line will effect a saving of about .'(0 per cent, so that the innovation will be well worth while. Tenders for the power line close on July I.