Rolling blackouts possible as Adelaide heads for top of 46C

The Country Fire Service says crews are being pushed to the limit as they continue to battle about 15 blazes around South Australia, with Adelaide heading for what could be its hottest day on record.

A maximum of 46 degrees Celsius has been forecast for the city after the mercury climbed to 43.7C on Wednesday, with more very hot conditions overnight.

The temperature only dropped to 29.9C just before 6:30am, with the temperature still above 35C at 2:00am.

Rolling blackouts could be on the cards in an attempt to reduce the pressure on the electricity grid.

The Government has confirmed power could be switched off to suburbs to prevent a system meltdown as air-conditioners kick into overdrive.

Government energy spokesman Vince Duffy said it may not happen, but people should be prepared.

"The general load-shedding is unlikely but it's still a possibility if there was further technical faults," he said.

Premier Jay Weatherill says efforts will be made to restrict any forced power outages to half an hour.

"If it does occur, in the first instance, attempts will be made to limit those to a period of half an hour so as to minimise the adverse affect on the well-being of people in their homes," he said.

"Should however that escalate, we've made arrangements for the Chief Executive of the Department of Communities and Social Inclusion to organise for vulnerable people who would be affected by such power outages to make sure they are coping."

Adelaide's hottest temperature on record, 46.1C, occurred in the January 1939 heatwave.