Students at Nowra TAFE took class in the dark on Friday afternoon.
The power was cut after a fire started on the grounds.
Leaf litter caught alight from a discarded cigarette, and the wind fanned the flames into a high voltage substation.
TAFE staff used a fire hose to contain the blaze, before a NSW Fire and Rescue Crew arrived to extinguish the fire completely.
“Their actions definitely helped,” crew commander Wayne Gerstenberg said.
“The fire could have caused a major incident, there were toxic fumes, toxic smoke coming out of a high voltage electrical substation.”
He said weather conditions have amplified the risk of fire in the region.
“Discarded cigarettes have always been regarded as a problem for starting not only these minor fires, but major bushfires,” he said.
“People don’t realise the ramifications of what they do.
“With winter staying dry, and getting the westerly winds, the weather’s a bit unseasonable, and the leaf litter on the road is drying out.
“People need to be aware that even though it’s winter it’s still a danger.”