New equipment at an electricity sub-station was blamed for causing a power cut which hit 38,000 homes in Oxfordshire yesterday.

Residents in Abingdon, Drayton, Steventon, Didcot, Wantage, Grove, Chilton and Harwell woke up to find there was no heating or lights after power went off at about 6.45am.

Southern Electric told customers on its emergency line that staff were trying to locate the source of the fault and that the power would be off for up to three hours.

Engineers managed to restore energy to all homes by about 8.40am. Spokesman Sharon Miller-McKenzie said: "Teams of engineers were sent to the area and power was restored to customers in phases.

"We're still investigating the cause of the fault. At first, we thought something may have hit one of our high-voltage lines, but that now seems unlikely. The focus of our investigation is an electricity sub-station in Drayton, near Abingdon, where new equipment has been installed recently.

"It's quite possible that there have been teething problems with this equipment and that's the most likely cause of the problem, although our engineers are still completing their investigation.

She added: "This kind of power cut affecting so many homes is extremely rare, and we would like to apologise to our customers who were inconvenienced early this morning when they were getting ready to go to work or take their children to school."

Ms Miller-McKenzie said 28,000 homes had their power restored by 7.30am. Drivers in the Didcot area reported that some traffic lights were also out of action, including those at the Milton interchange.

Michael Howden, of Steventon, said the village lost power in the early hours. He said: "It was certainly off at 6am when we woke up. It was back on by 7.50am and apart from the fact it shut the computer down, it didn't affect us."

In Abingdon, homes and businesses in the south of the town bore the brunt of the power cut. Eleanor Dangerfield, of Masefield Crescent, said: "I was thinking of getting out our camping gas heater from the garage to boil some water, but by 7.30am the power was back on, so we didn't need it."