Which plug adaptor do I need?

2The letters, and the one that does most of the work

Every plug shape has a letter from A to O. Type G is ours, three rectangular pins and a fuse in the plug, and the IEC lists it for the UK, Ireland, Cyprus, Malta, Malaysia, Singapore and Hong Kong among others, so in those places you need nothing at all. Type C is the two round pins of the Europlug, and it is the letter that matters, because the IEC says a Type C plug fits any socket with round holes 19 millimetres apart: the E of France and Belgium, the F of Germany, Spain and the Netherlands, the J of Switzerland, the K of Denmark, the N of Brazil, Italy’s combined sockets that take C, E, F and L, Israel’s H, and Thailand’s O. One two-pin adaptor does the continent.

What a two-pin will not go into: the flat parallel pins of A and B in the Americas and Japan, the flat pins in a V of Type I in Australia, New Zealand, China and Argentina, and the large round pins of D in India and M in South Africa. Those want their own adaptor, and the sheet names it. If your laptop lead has an earth pin, buy the earthed European adaptor: the IEC describes a plug pattern with earth clips on the sides and a hole for the French earth pin that fits both E and F sockets, and a Schuko-only adaptor without that hole sits badly in France, Belgium, Poland, Czechia and Slovakia.

3Voltage: the bit the adaptor does not fix

An adaptor changes the shape of the pins and nothing else. Britain runs at 230 volts, 50 hertz, by regulation. Most of Europe, Africa, Asia and Australia runs at 220 to 240, so a British appliance plugged in through an adaptor works as it does at home. The Americas, Japan and a few Caribbean islands run at 100 to 127 volts, and that is where things go wrong. The test is on the rating plate, the small print moulded into the body or the power brick: an appliance marked INPUT 100-240V, or 110-240V, is dual voltage and works anywhere with the right adaptor, says Electrical Safety First. One marked 220-240V only is not, and in Florida it will run feebly or not at all.

In practice: phone and tablet chargers are dual voltage (Apple’s are rated 100 to 240 volts, 50 to 60 hertz, and the others say the same on the brick). Laptops likewise. Hair tools are the trap. ghd says its straighteners, curve, rise and oracle run on any voltage, and that its air, helios and speed dryers and its glide and duet hot brushes are 220 to 240 volts only. Read the plate on yours before you pack it. For a 100 to 127 volt country a transformer will step the voltage up for a dryer, though Electrical Safety First says not to use one for electronic things like consoles and computers, which do not need it anyway.

4Two voltages in one country, and sixty hertz

Brazil runs most of its states at 127 volts and some at 220, the IEC says, and so does Morocco in parts; Japan is 100 volts everywhere but the frequency changes from 50 hertz in the east to 60 in the west. The sheet prints both figures where the IEC lists both, and the honest advice is to look at the socket label in the hotel, or ask. Frequency matters less than voltage: a dual voltage charger does not care, and Electrical Safety First says a 50 hertz appliance on a 60 hertz supply may work but not quite properly, its example being a clock that runs fast.

5One adaptor or a worldwide one

If the holidays are Europe, a two-pin Type C adaptor, or two, is the whole answer and it costs less than the coffee at the airport. If one trip is America and the next is Australia, a worldwide adaptor is one thing in the bag instead of three, with the caveat that it covers the sockets printed on its box and no others: the large round pins of India’s Type D and South Africa’s Type M are the ones a ‘universal’ adaptor most often leaves out, so look for those letters by name if that is where you are going. None of them is a transformer, whatever the box implies. The voltage question above still has to be answered by the rating plate on the thing you are plugging in.