The earth circuit remains the same of course – grounded somewhere along the line, hopefully, into terra firma. But the other two – Live and Neutral – have become Hot and Neutral and have halved from 240V to 120V. Great. Now half of my appliances don’t work and all my extension cables are rated to half the power they could safely carry before…. Here’s why:
- power = voltage multiplied by current
- current = power divided by voltage
Which also means when the voltage drops from 220V to 110V, the current must double in order to get the same power.
So when we hook up our vehicles to the mains here in Canada, the US, Mexico and much of what comes up, three things happen:
- Any appliance that doesn’t use a transformer will be running at half voltage, half power and only be as half useful because it can’t suddenly decide to draw double the current. This includes all our power tools, battery charger and hair clippers. For example, to run smoothly, the clippers need 240W – which, in the UK, means at 240V they are drawing 1A in current. Over the pond, they still draw just the 1A but at 120V – which means they only have 120W power – they run slow and it hurts when I shave. Is that why there are so many mustaches in certain parts of the world? No! (There’re other reasons for that). If I bought some clippers here in Canada, they would be designed to draw 2A thus giving me a pain-free, 240W.
- Gadgets that use a transformer such as laptops and the chargers for cameras and phones can handle the voltage drop and still give the correct power. Thank god for this. (But check the small print on the back of the black box before you travel to be sure your thing’s gonna work). This explains why most people are not concerned with the 240-120V drop and worry more about the difference in plugs and sockets. Mostly anything you can carry on the plane won’t have a problem once you use an adapter. Appliances that would have a problem are much more likely to have been bought locally and you’re just borrowing them – you’re not so foolish as to ship lamps, angle grinders, fridges and stuff half way round the world, now are you?
- Our extension cables can only carry half the power they could before. For example, if we borrow a hot plate to cook on which runs at 2000W, the current carried in the hook up is now 16A rather than the 8A we would be using back in Europe. The cables would have to be twice as thick, to carry the same power – which means America must use much more copper than Europe! (Note to the scavengers among us when things get really tight…)
Why the difference between 120 and 240? The simple answer is tradition for the Americans and efficiency for the Europeans. Mains voltage was around 110V back when it used to be DC and there were few regulations to protect people from getting electric shocks from badly built and designed equipment. A higher voltage causes much more of a shock but it was developed later when fewer people were less inclined to poke their fingers into these new-fangled holes in the wall.
So how do we get around all these issues? Firstly, in fact, there does exist, in most houses in America, a 240V outlet, and, in fact, mains is delivered to buildings at in 2 phases of 120V. With a clever bit of wiring the 240V becomes accessible for heavy duty appliances like heating, washing machines. However, the plugs have four pins – the Earth, The Neutral and two ‘Legs’ of 120V. Can anyone tell me how to wire an English socket to one of these plugs? Please.
And, the ultimate resort, is to produce our own 240V single phase power. Unfortunately, the solar panel only really kicks in when it’s very sunny and the inverter has a limit of 150W. Still, it could be the only native 240V single phase system on the North American continent.