Power was cut to 7000 houses, farms and businesses between Tantanoola and Mount Benson for two hours on Sunday morning.

The unplanned blackout began at 8.45am and emanated from the 33-kilovolt line which runs north from the Snuggery substation.

Among the towns to be affected were Millicent, Southend, Robe and Beachport.

Multiple SA Power Networks maintenance crews immediately patrolled the line but no cause for the outage was found.

Among those adversely impacted was Mark Pilmore who runs Acky’s Deli in Millicent.

Mr Pilmore said he took the decision mid-morning to close his George Street premises for the day.

“I received a text message from SA Power Networks to say the power would not be back on until 3.45pm,” he said.

“I did not want to have my staff standing around all day and being paid Sunday penalty rates.

“Based on that text message, I closed the shop and lost almost a full day’s trade.”

In response, SA Power Networks spokesman Paul Roberts said his company was well aware of the inconvenience caused by such unplanned outages.

“The estimated power resumption times are based on such factors as the size of the outage and the amount of patrolling which needs to be done,” Mr Roberts said.

Meanwhile, SA Power Networks has advised Millicent residents of a planned outage on Sunday for maintenance purposes.