If you are based in the UK then your standard plug will generally not be usable anywhere abroad without an adaptor and if you are from North America the same applies. The voltage is generally in the 220-230 range and for the most part a "continental" two pin configuration will be the norm. However, there are subtle differences from country to country and in quite a few two or more variants are found. Apparently, an international committee has been meeting for more than 50 years to unify the plug convention but as yet there is no tangible result, the Uk plug being the most striking proof that people cannot agree in this matter. Each and every country seems to think theirs is the best.