Breakers

A row of vintage circuit breakers stands in the high-voltage hall at Wangi Power Station, each one mounted in its own steel cabinet about the height of a person. The breakers are bulk oil units, painted institutional grey, the colour darkened in patches with rust. Brass nameplates on each cabinet show the circuit label, the voltage rating, and the manufacturer. The handles for manual operation are still in their last position. Wiring and busbars run between the cabinets in heavy gauge, all dead now. The hall is quiet. The cabinets are bigger than they look from the outside; most of the switching mechanism is below the floor.

Bulk oil circuit breakers were the standard high-voltage switching technology in postwar power stations. Each breaker was a sealed cabinet containing the contacts immersed in insulating oil, capable of interrupting a fault current of tens of thousands of amperes without damage. Wangi's breakers were installed at the original 1958 build and worked continuously for the full life of the station. After closure in 1986, the breakers were isolated from the network and left in place. Removing them involves draining and disposing of hundreds of litres of insulating oil from each unit, which has not been a priority. The breakers in this photograph are still as they were left.