Fire in cables at Penrose substation hits homes and businesses, traffic lights and freezers.
Power should be restored to all Auckland suburbs by 5am tomorrow, lines company Vector says.
The company late this morning released its latest estimates for when power was likely to be restored following yesterday's major blackout, which was caused by fires at the Penrose substation.
About 18,000 customers in eastern Auckland remain without power, down from 39,600 last night.
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Vector spokeswoman Sandy Hodge said the St Johns feeder -- which delivers power to Meadowbank, St Johns and Orakei -- should be back in operation at 8pm today.
The Sylvia Park cable should be back up by 11pm, Carbine Road by 1am tomorrow, Mt Wellington by 2am and the rest of Remuera by 5am.
Ms Hodge said the estimates would be updated if they changed.
Work on the fire-damaged cables at the Penrose substation was progressing well, she said.
"All available crews are working on these cables in order to repair and then reinstate them," she said.
"In the meantime, customers that have been restored in the affected areas are asked to conserve power as much as possible so we can back feed more areas.
"There is a bad patch of weather expected over the Auckland region today, so please ensure that garden furniture is secure along with tarpaulins and trampolines."
The Auckland Emergency Coordination Centre, which was activated yesterday, remains in operation this morning.
Civil Defence said nine road intersections remained without power, four of which were being managed by police officers.
Bus and rail services were mostly running without disruption, although four rail stations at Orakei, Sylvia Park, Glen Innes and Meadowbank had no power.
All hospitals were now on mains power. Health services had coordinated residential care teams working in affected areas to help those who were most vulnerable.
Westerly winds were expected to be gusty in Auckland later today, with the MetService forecasting winds of up to 100km/h in exposed places until 6pm.
"These winds are not expected to cause widespread damage but it is possible there could be localised power outages and fallen trees could during the afternoon," Civil Defence said.
The continuing blackout has prompted safety warnings from the Fire Service after two worrying incidents overnight.
Assistant area manager Mike Shaw said a woman was burned in an accident involving a methylated spirits camping stove.
In the second incident, a family left a diesel-powered generator running in a closed-up basement before they went to bed.
"Diesel-fired generators emit carbon monoxide and this could easily have filtered up through the floorboards and killed the sleeping family.
"Luckily, it ran out of fuel before this could happen."
Mr Shaw urged Aucklanders affected by the outage to follow basic safety rules when using generators, gas barbecues and lanterns.
He said portable barbecues, LPG patio lights or other equipment should not used be inside unless there was plenty of ventilation from open doors and windows.
"When changing the gas canisters or refuelling, make sure you are well away from any candles, or any other source of ignition."
Mr Shaw said generators should be kept outdoors, or in a well-ventilated area to avoid carbon monoxide poisoning. The fuel should be stored separately.
Households using candles should make sure they were on a stable, non-combustible surface, well away from curtains or bedding and out of the reach of children. People should ensure they were blown out before going to bed.
Mr Shaw said electricity would come back on without warning, so people should make sure all switches were off and no stove elements were on.
The blackout has also prompted health concerns over spoiled food.
Auckland Civil Defence and Environmental Health said households and businesses should take care with food that had sat in fridges and freezers without power.
Readily perishable food should be thrown out if the power had been off for more then 24 hours, or if chillers were opened.
Food left in fridges or chillers without power for less than 24 hours must be checked, but should be safe if chillers were not opened, or opened only briefly for ice to be added.
Civil Defence said perishable foods in the chiller, such as fruit and hard cheeses, may still be safe if they were not showing obvious signs of spoilage.
Partially thawed food in the freezer should be completely defrosted and used immediately.
Food that did not thaw and remained frozen could still be used. However, frozen food that had defrosted and was then refrozen when power was restored should not be used.
The signs of defrosting would not always be obvious, but included misshapen products, drips from packaging, packages stuck together, or pooling of frozen fluids in the bottom of sealed packages.
Popular school holiday attraction Kelly Tarlton's, which was forced to close its doors to the public yesterday due to the power cut, has reopened today.
A spokeswoman said a temporary generator was in use and all areas were open, but customers would not be able to book online. Kelly Tarlton's would give the online booking discount at the ticket desk while the function was unavailable.
Assistant Area Fire Commander Dave Woon said it could take up to two weeks to report on the cause of the blaze that caused the power cut.
It was one of the more difficult blazes the Fire Service has had to work on, particularly as firefighters had to wait about an hour to ensure the power at the major substation was isolated and they would be safe to approach the trench.
By that time oil pressure pumped into the cables had seeped throughout the trench, fanning the flames and causing an intense heat to build up. Foam was used to knock back the flames so firefighters could access the 1.5-metre deep trench but Mr Woon said it then took some time to remove heavy concrete tiles covering the cables before a heavier foam could be used to suffocate the flames.
"It was dark and smoky and that was a hard job. I had 35 people there working with the foam and tiles and this was a very technical job, not something we do every day. But we had a good outcome," he said.
5 Top power outage tips
1 For light, a torch is safer than candles.
2 Switch off sensitive electronics such as the TV, computer, stereo and video recorder until after the power is restored. These can be affected by a power surge when power comes back on.
3 Keep the fridge closed. Food in refrigerators and freezers will last longer if the doors are closed.
4 Turn off all appliances, including the stove, kettle, and heaters. This ensures they don't come back on when no one is home.
5 Street lights and traffic lights may not be working.
Sam Boyer, Nicholas Jones, Brendan Manning, Bernard Orsman, Sophie Ryan, Rebecca Quilliam, Susan Strongman, Vaimoana Tapaleao, Teuila Fuatai.
- Additional reporting Businessdesk