Cyril Stobie's poles idea from 1924 grows to 725,000, and state icon, taking power to South Australia's streets
Stobie poles at the intersection of Main Road, Shepherds Hill Road and Coromandel Parade, Blackwood, in about 1938, carrying electricity into the Adelaide Hils. The concrete Stobie poles replaced wooden ones (such as seen at left).
Image courtesy State Library of South Australia
Stobie poles – more than 725,000 of them – were a useful oddity only widely used in South Australia. They were also, oddly, state icons despite being widely regarded as ugly and a motor traffic hazard.
The Stobie, a powerline pole made of two steel joists held apart by a slab of concrete, was invented in 1924 by Adelaide Electric Supply Company engineer James Cyril Stobie. His idea overcame two South Australian problems: scarce timber and abundant termites. SA Power Networks (successor to the Electricity Trust of South Australia) continued to make stobie poles at a plant in Angle Vale in the 21st century.
Cyril Stobie, the only son and eldest of four children, was a brilliant student at Glenelg Public and Pulteney Street schools, who won a scholarship to the South Australian School of Mines and Industries.
Stobie’s education was halted when he took over the family grocery shop at Mile End after his father died in 1912, to support his mother and sisters. In 1915, he enrolled as an evening student at the School of Mines and Industires and gained diplomas in mechanical and electrical engineering. (Fond of sport, he excelled at swimming and won the from Grange-to-Henley Beach race in 1922.)
In 1916, Stobie joined the Adelaide Electric Supply and continued his engineering studies part time at Adelaide University. F. W. H. "Freddy" Wheadon, the company’s chief executive, became his mentor and a lifelong friend.
As chief draftsman, Stobie invented his pole to carry electricity cables and telegraph wires in 1924. Adelaide Electric Supply paid him £500 for the patent rights. The first poles were erected in South Terrace, Adelaide, in 1924, and were then used extensively in building the electricity transmission and distribution infrastructure throughout the state.
The new poles, coupled with the significant generation capacity of the Osborne Power Station, rapidly brought electricity supply to the outer metropolitan and near rural regions of South Australia from the 1920s. Stobie poles were also used on the main northern extension line that ran at single-phase 4,000 volts fromHarrow substation to Gawler. In 1936, Stobie converted a Sterling coal truck so it could install 21-metre long concrete-steel poles weighing 7.7 tonnes.
The Electricity Trust of South Australia took over from Adelaide Electric Supply in 1946 and Stobie became chief design engineer. In that year, Stobie and Wheadon, with John Ragless Brookman, formed The Stobie Pole Syndicate to patent the design and then sell it or the manufacturing rights.
The Hume Pipe Company became their first agents but, despite many international inquiries, South Australia largely remained the only place where they are widely used.
The easy-to-make rot-, fire- and termite-proof Stobie poles carried from 240-275,000 volts and varied from nine to 26 metres in length; also heights to 36 metres were feasible. The expected service life of a Stobie was more than 80 years,