240 volts v 110 volts

[kentishbear]

Why does Britain use 240 volts whilst most of the other countries i know use 110 volts?

Could Britain become twice as energy efficient if we halved the power output to run all our electrical appliances and therefore reduce pollution and help slow the depletion of the ozone layer?

or doesnt it work that way ?  so thats why we dont do it

[netibiza]

I think you'll find most of Europe uses 220 -240v.  Surely its only USA and Canada that use 110v?

[kempie]

The vast majority of countries use 220V

Worldwide AC Voltages and Frequencies

[Pinotage]

The reason US uses 110 volts is interesting. Apparently the authorities were worried about possible dangers of an public electricity supply, and limited it to 100 volts, with a 10% marging of error. Edison went ahead with maximum he was allowed - 110.

AFAIK, the rest of the world settled on a more efficient 220 - 250 volts. The UK is stepping down its domestic voltage to 220 to match the rest of the EU. 

[pjm007]

Pinotage, Would the stepping down in voltage affect any electrical appliances we have ?

[hertz]

The voltage is not being stepped down. It was always previously declared at 240 volts, plus 6% or minus 6%. This is known as the Statutory Limits. Now the electricity supply companies are declaring the voltage as 230 volts, plus 10% minus 6%.

 Basically the upper limit which can be supplied is 253 volts and the lowest limit 216 volts. There has to be some leeway due to distances from substations (volt drop) and different loads at different times of day affecting the voltage. 

Most electrical appliances *should* work within this voltage range.

[Ray the DJ]

Hertz,
Is correct. 
Why would the UK want to reduce its voltage? 
Any EU appliance will work here and vice versa.
The cost of reducing the voltage nationally would run into billions of pounds.

[HRH Rainier]

To answer the second part of your question: The fact that the US VOLTAGE is roughly half the UK voltage, doesn't mean they use half the POWER, a US 100 watt bulb still uses 100 watts of power. It draws twice as much current as the UK equivalent.

[netibiza]

and 110v isn't any safer - you'll still get a shock

[rojash]

Not quite true netibiza, the reason the US lightbulb draws more current is that it has a lower resistance beacuse it's specifically designed for a power of 100 watts. However an Englishman and an American have the same resistance, so (all else being equal) less current will pass through the American who sticks his finger in the socket. In other words, he will receive a smaller (and therefore less dangerous) shock.

[netibiza]

Well rojash in the 70's here we had both voltages 110 and 220v and they were both shocking.

[goobles117]

Not true rojash. 220/240V (We get 240V In Australia) is a "Safe Voltage" 240V throws you off it, something like a live wire (providing that you dont grab it) 110V does not seem to do that.
I was working on a live PC a few weeks ago (Supid yes I know, and I learned my lesson) and I was electrocuted, I was thrown accross the room, the PC Case still wrapped around my hand/arm, and broke the plasterboard wall of my bedroom. Not a very nioce experience, and I wouldnt want to do it again. My father who used to work for ETSA said that if it was 110V, I probably would have been killed because the voltage wouldnt have thrown me off..althought I do not know this for certian, I have been told by many people

[rojash]

Sorry goobles117 but I can't accept the word of a dead person on this, which is what you would be if you were electrocuted. Check you dictionary.

[jjaammeess]

240v is better ----to get the same power into our houses we would need heavier cables

[jjaammeess]

I can verify what goobles117 said .I got a direct 240 v shock when holding a metal encased  instrument.Without thinking I instantly threw it across the room hitting the wall about 8 feet away.I got a severe shock but no other damage to me

[Sequin]

If an appliance has the same power rating (wattage) then for a lower voltage, it needs a higher current as Watts=Volts x Amps

The danger of electrocution is dependant on the amperage - the higher it is, the more dangerous the shock. A static charge can be thousands of volts, but only a very small amperage, so it may be uncomfortable, but unlikely to cause damage. A low voltage shock carrying a high current can kill.

A 110v supply would be more dangerous, as it would have to have a higher amperage to provide the same power

[Pinotage]

Well Hertz, you say my statement that the voltage is being stepped down in not right, but then go onto say its dropped from 240 to 230v. :)

I was incorrect to say its being stepped down, in fact its been doing so for gradually ten years until 2003. And the reason is to get a European standard of 230v.

[jjaammeess]

sequin is wrong because resistance isthe same therefore with the lower voltage the current would be less and the power would be 1/4                                           

[BillyBB]

I heard a few years ago that the power companies in England reduced the voltage purely as a cost saving measure, there was worry at the time that it could affect the output of microwave ovens.

 

I have heard recently from an employee of one of our major power supply companies that they are slowly reducing the voltage to be in line with Europe.

[rojash]

Some pretty fundamental errors in your reasoning Sequin. The reason a high static voltage is reasonably safe is that there is only a minute current AVAILABLE. In the case of the mains electricty there is a high current available regardless of whether you are using 110 or 240 volts. In this case it's not so much the available current that matters, it's the current drawn. This is governed by only two things: The voltage which drives it and the resistance of the circuit. Given that the major resistive component is constant (i.e. the person with their finger in the socket), less current will pass if there is less volatge to drive it. As I stated earlier, in order to work at the same power, the US lightbulb will need to draw more current, and in order to do this, it is manufactured wih a lower ressistance.

Incidentally most AC shocks will tend to throw you off as your muscles contract and relax with the 50 or 60 Hz cycle. DC tends to send the muscles into spasm.

[bluka]

Can't pretend I know the reason why, but 110v is regarded as safer.

On construction sites, power tools are stepped down from 240v to 110v using a transformer (yellow coloured box).

I guess there is a greater likelihood of cutting the wires or getting the items wet, but still, the recommended maximum is 110v