UK Don't boil the kettle while charging your electric car because it will blow the fuse, National Grid warns

Don't boil the kettle while charging your electric car because it will blow the fuse, National Grid warns

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.

Reply to
BurfordTJustice
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IME, main fuses are pretty tolerant of short-duration, low-level overloads. If you have an 80A main fuse running at 100% load, I would doubt that the additional 12A for a kettle for the 3 mins or so that it takes to boil will blow it.

There's probably a formal specification somewhere, but in practice I've found that fuses will run up to around 150% for quite a long time. They don't really start "blowing" (as in failing immediately) until you get around 200%.

And isn't it possible to ask for 100A if you need it? I've always been able to specify 100A on all the properties I've had connected; but perhaps that's because none of them have been out in the boonies.

Reply to
Caecilius

That is just strange to Americans. The minimum allowable service in the US is 100a at 240v (specified in the electrical code) and it has been that way for at least 50-60 years. Most common is 200a and 400a is not unusual in a bigger house. A true "mansion" like Al Gore has would have 1200a or more.

Reply to
gfretwell

+1

200A here

And boy, if the UK is going with electric cars and they have 60 to 80 amp services, either it's going to take a very long time to charge those cars or they will need a service upgrade. I think chargers for electric cars can need and use a 50A circuit. And this is basic energy physics that new battery technology, chargers, etc isn't going to fix.

Reply to
trader_4

The utility fuse is only intended to protect the transformer and it is on the primary side, typically sized at 150% or more of the transformer rating. Service conductors going to the home should be regarded as not really having any overload protection.

Reply to
gfretwell

And that's why I'm stuck with 150 amps - the underground feeders would be oveloaded at 200 amps, and replacement would cost ME $8000.

Reply to
clare

Is the service lateral direct buried cable or in conduit? If it is 2" conduit you should be able to pull the old wire out and pull in 2/0 copper or maybe even 4/0 aluminum but that is a tough (but legal) pull.

Reply to
gfretwell

several hundred feet of cable from the transformrt vault to the house

- not sure if direct burial or in a transite conduit. If in transite, shared with neighbor and definitely NOT pullable. They ralked about trenchless installation - replacing the existing cable without removing the old cable when it was decommissioned due to the expense of removing it. The root systems of several large trees, both on my property and city property, are involved, as well as gas, water, and sewage lines. Phone and cable are not involved as they enter from the rear property line.

Reply to
clare

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