Stobie Pole, SA

In the early part of the 20th Century the Adelaide Electric Supply Company was expanding the electrical distribution network.

Traditionally the distribution of electricity was by cables and wires suspended on timber poles. However, in South Australia there were several challenges to the use of timber poles – South Australia did not have a ready supply of suitable straight timber, the corrosive soils and termite infestation.

The company needed to import timber poles from interstate which due to the soil conditions and termites did not last.

An Adelaide Electric Supply Company engineer, James Cyril Stobie, developed a pole manufactured from steel and concrete. The pole consisted of two steel I beams connected by bolts. The bolts provide a separation between the two steel beams. This space was filled with concrete.

These poles became known as Stobie Poles.

Stobie applied for a patent for the pole on 15 July 1924 and was granted on 24 February 1925 (Australian Patent number 19240186874). Stobie was paid £500 granting Adelaide Electric Supply Company a free licence to manufacture and use Stobie Poles.

The poles were resisted to termites; they did not burn and were resilient to flooding events. The typical life of a timber pole is 20 years and a Stobie Pole has a life of 80 years.

Stobie Poles are currently manufactured at SA Power Networks (the current incarnation of Adelaide Electric Supply Company) Angle Vale facility at a rate of 4,500 per year. There are about 650,000 across South Australia.