In brief

• Auckland couple’s fuse melted after charging electric cars during off-peak hours.

• Incident exposes potential weaknesses in New Zealand’s electrical infrastructure.

• The couple said the Vector technician confirmed the fuse melted due to excessive power draw.

• Vector did not officially respond to Centrist queries. 

• However, CEO Simon MacKenzie inferred to RNZ climate change correspondent that NZ may lack the necessary infrastructure for mass EV adoption. 

Potential infrastructure weakness

An Auckland couple’s main service fuse connecting their house to the power grid melted after using free off-peak hours to charge electric cars and run appliances, exposing potential infrastructure weaknesses.

The couple, who wish to remain anonymous, shared their experience with Centrist.co.nz, shedding light on a potentially widespread issue that could pose serious fire hazards.

They recounted how their routine night of charging both of their electric cars, running the dryer, and possibly other appliances like the dishwasher, ended in a complete blackout. 

“I was downstairs with the dryer on, and suddenly, everything went black. It wasn’t just a tripped switch; our entire house was out while our neighbours still had power,” the wife explained. 

They initially believed it was a tripped switch localised to a part of their home.

“Since three years ago when we started driving electric cars  we’ve had power switches tripping, but only in specific areas of the house. This time none of them had tripped, they were all up and they were all on,” the husband said.

“We went to the garage where our main power box is located, but there was no reaction when we tried to reset the main switch. We were disconnected from the grid,” she said. 

Melted fuse 

After calling Vector, the power company, a technician arrived within half an hour. He quickly determined the source of the problem: a melted fuse in the underground connection to their home. 

“He showed me this fuse that was the size of two hands that was now twisted and melted,” the husband said. 

The couple reported that the technician told them the melted fuse looked like the result of an overuse of power, but he could not tell them how or when. 

“He replaced it, but it was alarming to see how much power we were drawing at once,” he said.

Did utilising free off-peak power to charge two EVs cause the potentially hazardous meltdown? 

The couple had switched to a power plan offering free electricity from 9 PM to midnight, an incentive to shift high-energy tasks to off-peak hours. However, the simultaneous charging of two electric vehicles, combined with other household appliances, proved too much for their electrical infrastructure. 

The couple say they use both a wall charger and a regular connection to charge their two cars, with their vehicle insurance covering the wall charger. 

The couple note that their home’s modern, energy-efficient design, in fact, consumes a lot of  power due to their electric vehicles and other technologies.

“Our house, because it’s not even a decade old, in theory it consumes less power: Insulation, double glazing, LED lights, all together we consume less power. But with the add ons: the cars, the technology, it’s actually more. The cars are the main thing absolutely,” he said.  

Staggering power usage

The couple has since adjusted their charging schedule, starting one car at 9 PM and the other at 1 AM, to avoid such incidents. 

They have also stopped running high-energy appliances like the dryer and oven during the free power hours.

No official comment from Vector to Centrist

Centrist has heard anecdotally from Vector customer service reps that the company is aware that charging EVs at home has the potential of overwhelming the grid. However, the company has not responded to several requests to comment. 

However, on 25 July, an RNZ report by climate change correspondent Eloise Gibson featured Vector chief executive Simon Mackenzie. He acknowledged for what appears to be the first time in public that New Zealand may not currently have the capacity to handle widespread home charging, especially at peak times.