Three crews arrived on scene shortly after 11am, but were unable to make headway on the blaze until electrical authorities could turn off the power.

Tamworth Fire and Rescue NSW superintendent Tom Cooper said a Triple Zero called alerted emergency services to the unfolding situation.

"The electrical authorities got there at 11:51am, the power is isolated and at the moment firefighters are gaining access to look at whether there are fire extensions inside the walls and roof, they think it may have gone in," he said.

"It would be a slow, smouldering fire so they will have to use a thermal imaging camera to make sure it's put out completely.

"At this stage the switchboard is severely damaged and it was arching badly, so firefighters are checking the roof for fire extension."

When switchboards catch fire, electricity has to be turned off at the power pole otherwise electricity will still be live from the wire down to the meter box.

That means fire from the meter box has the potential to burn all the way into the wall and into the roof.

Read also:

Firefighters are still at the scene and arrived five minutes after the urgent call to emergency services, Mr Cooper said.

"They give off a fair bit of smoke, that electrical stuff," he said.

"It is dangerous until you turn the power off."

It's not clear whether the residents were home at the time of the fire. Paramedics attended the scene and reported that nobody was injured.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: