British plug

British plug
This plug is the modern British BS 1363 13A plug. It was introduced as a replacement for the older types D and M in the 1950:s. It sports an unusual feature, namely a fuse. The rating of the fuse corresponds to the current carrying capacity of the attached cord. The fuse is part of a system, called "ring final circuit", or less formally, ring main. Unlike the conventional radial circuit used with all other sockets, the ring final circuit has a cable going from socket to socket ending up where it started: At the fuse. As the cables are "parallelled" a higher fuse rating can be used. (30 or 32A compared to the 16-20A used with radial circuits) The pros and cons of the two layouts will not be considered here. However, the larger fuse in the fuse box means that the cord from the plug to the appliance is protected from short-circuit by the fuse in the plug. Therefore, only fused plugs and adapters should be used with this type of socket. This plug always has three pins, even if the appliance is ungrounded, in which case the ground pin is plastic. The reason for this is that the designers endowed the socket with a novel feature: Child safety shutters. The solution chosen was one where the ground pin unlatches the shutters and thereby makes it possible to insert the line and neutral pins. Some modern sockets have the international style shutters, which are opened by applying equal pressure on line and neutral pins.

Plug with two square pins and a long square ground pin, arranged in a triangle

This plug is the modern British BS 1363 13A plug. It was introduced as a replacement for the older types D and M in the 1950:s. It sports an unusual feature, namely a fuse. The rating of the fuse corresponds to the current carrying capacity of the attached cord.

The fuse is part of a system, called "ring final circuit", or less formally, ring main. Unlike the conventional radial circuit used with all other sockets, the ring final circuit has a cable going from socket to socket ending up where it started: At the fuse. As the cables are "parallelled" a higher fuse rating can be used. (30 or 32A compared to the 16-20A used with radial circuits) The pros and cons of the two layouts will not be considered here. However, the larger fuse in the fuse box means that the cord from the plug to the appliance is protected from short-circuit by the fuse in the plug. Therefore, only fused plugs and adapters should be used with this type of socket.

This plug always has three pins, even if the appliance is ungrounded, in which case the ground pin is plastic. The reason for this is that the designers endowed the socket with a novel feature: Child safety shutters. The solution chosen was one where the ground pin unlatches the shutters and thereby makes it possible to insert the line and neutral pins. Some modern sockets have the international style shutters, which are opened by applying equal pressure on line and neutral pins.

Type G