Macleay Street Re-opened After Underground Electrical Fire

Published: 21st November 2006

At 2:57 pm on Sunday 20 November firefighters from Darlinghurst Fire Station responded to a call that reported fire under the pavement on Wylde Street near St Neot Avenue at Potts Point. On arrival they were confronted by a cloud of dense white smoke billowing from an underground pit. Fearing an electricity transformer fire, the Station Commander cordoned off the area and called for additional resources including the New South Wales Fire Brigades' Hazardous Materials (HAZMAT) response unit.

Police closed Macleay Street and firefighters used several carbon dioxide gas fire extinguishers as a first aid measure. Fires involving live electrical equipment present a special problem because water, used to extinguish most fires, conducts electricity. Anyone applying water to an electrical appliance risks electrocution and severe burns. Carbon dioxide is a very cold gas that excludes oxygen and does not conduct electricity. Hazardous Materials firefighters then used a thermal imaging camera to identify the source of the smoke and a laser thermometer that remotely indicated temperatures exceeding 250 degrees Celsius. Gas detectors were used to ensure nearby residents were not exposed to toxic smoke.

Fortunately, the fire only involved the insulating material. The electricity authority was unable to disconnect power immediately and the decision was made to extinguish the fire with more carbon dioxide. In total, 46 kilograms of gas were discharged through a hose line from the Fire Brigades’ special carbon dioxide fire engine. This reduced the temperature significantly. Firefighters standing at a safe distance then used a high pressure water fog to further cool the unit. The small droplets of water in such a fog are also unable to conduct electricity.

With the smoke dissipating, Macleay Street was reopened shortly afterwards at 4:50 pm. Firefighters remained on scene for some time to confirm the fire was completely extinguished.