About 80 per cent of Vector's customers on the Auckland network are on controlled rates, Ms Hodge said.
"It might be called 'anytime' or 'economy rate' or something that their retailer calls it - it won't be a name like 'hot water control'," she said.
"It's the rate that they would have accepted with their retailer."
However, many customers who contacted the Herald this week to complain about the outages were unaware they had signed away their hot water for cheaper rates.
Remuera resident Eileen Ferrer said she had no idea she had signed up to controlled rates until she came home to no hot water on Tuesday night, despite her electricity having finally been restored. It was only when she spoke to her retailer Mercury Energy yesterday that Ms Ferrer discovered she was on controlled rates.
"They explained that it was to do with the type of meter I have. I had absolutely no knowledge of that until now.
"I knew nothing about it when I signed up with them and was never given the option to opt out of it."
Ms Ferrer described the system as "extremely misleading" and said she had since asked to opt out of the controlled rate system.
Customers were advised to check with their retailer whether they had signed up for controlled rates.
Ms Hodge said it was "very unfortunate" that some affected residents had paid tradespeople to check their hot water cylinder only to be told that there was nothing wrong with it.
However, the company had yet to confirm whether compensation would be offered, which would be determined following a joint investigation with Transpower.
Those who still had issues with their power were advised to log their complaints to complaints@vector.co.nz.
Meanwhile, the Fire Service confirmed it requested power be cut to 85,000 customers serviced by Transpower's Penrose site during the Sunday morning fire for safety reasons.
Assistant area manager Mike Shaw said staff would have been unable to battle the fire - which caused power cuts to parts of Auckland's eastern, southern and central suburbs - safely if the power site had remained live.
"You can't send in firefighters to a fire at a power station and not have it [the power] switched off. There's just no way," Mr Shaw said.
Strict safety protocols, such as prohibiting the lifting of your arms above your head, are in place when the site is operating at 100 per cent, so it was imperative the electricity be turned off to minimise the risk, he said.
The fire, which broke out in a trench containing cables supplying eastern suburbs, has cost retailers millions in revenue and inconvenienced thousands of residents.
- Additional reporting Teuila Fuatai
Power line
Saturday
11.30pm - A number of homes lose power after a fault with a feeder at the Remuera substation. Vector says this is an isolated incident but will look into it as part of its investigation.
Sunday
2am - Fire breaks out in cable trench supplying power to Auckland's eastern suburbs at Transpower's Penrose substation. Power cut to 85,000 people in central, south and east Auckland.
6pm - Power restored to Onehunga, Epsom, Penrose, Te Papa, Rockfield, Newmarket, Westfield, Ellerslie and Glenn Innes; 39,600 people in Sylvia Park, Remuera, Mt Wellington, St Johns, Orakei and St Heliers in the dark overnight.
Monday
5.30am - St Heliers, residential customers in Mt Wellington and half of Remuera restored; 18,000 customers remain without power for much of the day. Many are also without power late into the night.
Tuesday
7am - All but 324 customers reconnected.
4pm - Vector says all customers have power, but warns it is limiting hot water usage in parts of Auckland so its network does not become overloaded while work is carried out on two cables.
