A plug is part of an arrangement for allowing electrical devices to be moved from place to place. A plug is fitted to the end of a cable and normally has two or three pins sticking from it. These fit into a socket in a wall.
When the device is to be moved, the plug is simply pulled from the socket.
The part of the plug that is handled is called the plug casing. This is made of plastic which is an insulator. Electricity from the mains cannot pass through the casing so the casing is safe to handle.
People across the world use a number of different shapes of plug and socket. Below you can see European and North American plugs. Each type works perfectly well, although only the UK version has a fuse. But you can see why you would need a travel socket if you travel oversees.
