Electric car owners have been warned that if they attempt to boil a kettle while charging their car it will blow the fuse. The National Grid expressed concerns that an average size 3.5kW battery charger would take 19 hours to fully charge a car battery, even when it is 25 per cent full.
A "thought piece" document obtained by the Financial Times warned that a more powerful 11kW device would still take six hours to charge a car battery and during that time, the use of everyday items such as kettles and ovens would blow the fuse.
"The average household is supplied with single phase electricity and is fitted with a main fuse of 60-80 amps," the National Grid said.
"If one were to use an above average power charger, say 11kW, this would require 48 amps. When using such a charger it would mean that you could not use other high demand electrical items... ?without tripping the house's main fuse." The warnings come just weeks after the Government announced plans to ban the sale of new diesel and petrol cars by 2040 in a bid to encourage people to buy electric vehicles.
However, motoring experts immediately expressed concern, noting that it would place unprecedented strain on the National Grid.
Most electric cars will require a battery capacity of 90 kilowatt hours (kWh) to make journeys of around 300 miles, National Grid believes.
It suggests that the ability to travel longer distances without stopping to recharge will be a "must have" if motorists are to abandon petrol or diesel cars.
The company suggested that building several thousand "super fast" charging forecourts - similar to modern day petrol stations - would be preferable to a "large scale rebuild of the domestic electricity infrastructure" by fitting homes with the maximum 100 amp main fuse. Michael Gove, the Environment Secretary, has warned that Britain "can't carry on" with petrol and diesel cars because of the damage that they are doing to people's health and the planet.
"There is no alternative to embracing new technology," he said last month.