Mrs Kinross said she was in her front garden when her fuse box caught alight at 12.45pm.

"I heard the power box make a noise and then there was black smoke billowing out of it and a few flames on the top of the box," she said.

"I rang the fire brigade and told them it was on fire."

Mrs Kinross said smoke could then be seen billowing out of the roof and the Country Fire Authority told her the inside of the roof was on fire. 

She said one wall and parts of the roof were damaged but the house was otherwise untouched.

"The firemen were wonderful - there were five trucks there immediately," Mrs Kinross said.

"(The firemen) scurried up the roof."

She said fire crews from Castlemaine, Guildford and Campbells Creek attended.

She said early investigations concluded the fuse box had a loose wire.

A CFA spokeswoman said the fire was electrical but could not comment on the exact cause of the fire.

Mrs Kinross said the fire wasn't started by her smart meter, as she saw her fuse box set alight.

She said the house was 15 years old and the fuse box was inspected regularly.

"It was just a freak thing that happened," she said.

"Why it erupted then, who knows?

"It was just lucky I was home and outside and saw it."

Mrs Kinross said the damage would be covered by her insurance.

But she said three large water tanks would have to be drained, because the water had become contaminated with soot.

She said she and Larry felt lucky the damage to their house was contained.

"It could have been a lot worse," she said.

She said she was happy her fire alarm went off straight after the explosion.

"If it had happened at night we couldn't have slept through the alarm," she said.