Introduced in the United Kingdom in 1947, the three-pin BS (British Standard) 1363 plug and socket have been adopted by numerous countries worldwide. Known as Type G outside of the UK, the plug is used by nations including Ireland, Hong Kong, Malaysia, Tanzania, Saudi Arabia, Iraq, and many others. If you’ve used one, you’ll be familiar with its sturdy feel, which is satisfyingly secure when connected to an outlet. When compared to the BS 1363, other designs, such as the two-pin Type A plug used in North America, and especially the “Europlug” (notorious for spontaneously dropping out of wall sockets), can feel a little flimsy.
There’s a significant amount of clever engineering beneath the BS 1363’s hefty design, though these ingenious safety features aren’t immediately apparent. For example, the three wires inside the plug are different lengths, with the earth wire longer than the others. This ensures that if the cable is pulled with force from the plug, the live and neutral wires should detach first, with the earth wire remaining in place longer, thus retaining its crucial function as a safe electrical pathway for any fault.
Likewise, you may have noticed that the pins are also different lengths, with the earth pin (positioned at the top of the triangular pin arrangement) a fraction longer than the other two. This feature has two safety functions, both related to how the plug is inserted into the corresponding BS 1363 socket. First, the live and neutral connections within the British socket are covered by spring-loaded plastic tabs, keeping these current-carrying connections inaccessible until the longer earth pin has pushed a linked tab out of the way. Second, the earth pin’s increased length means that a path to earth between the plug and the socket is always connected before the shorter live and neutral pins make their respective connections.
Additionally, short sections of plastic insulation at the base of the live and neutral pins mean that accidental contact with these electrical contacts is impossible, even with the plug only partially inserted into the socket.
Plug it in:
- The design features of the BS 1363 plug, combined with well-insulated components and a replaceable internal fuse which will blow if the rated current is exceeded, make the humble British plug an ingenious bit of engineering—and arguably the safest domestic plug design in use today.
- However, plug design isn’t the only consideration for electrical safety. The UK uses an AC voltage of 240V, compared to the 120V supply found in the United States, potentially making accidental electrical shocks more hazardous.
- Electrical equipment wasn’t always supplied with plugs. While the primary use for electricity in the late 1800s and early 1900s was for lighting, electrical appliances such as vacuum cleaners, irons, and fans were supplied with bare wires, which would either be connected to the light socket or directly to the household wiring circuit.
