Electrical Plug Types

Some bad jokes, a little history, and various facts about electrical plug types

Here's a terrible little Dadaist electrical plug joke: How many electrical plug types does it take to operate a global electrical appliance? Thirteen. OK, here's a better one: What do Prince Charles and a British 3-pin type G electrical plug have in common? They're both useless outside of Britain and its colonies. Hmm. Apparently there aren't any good electrical plug jokes, so instead here's some information about electrical plug types.

The history of electrical plugs

Everyone has heard of Thomas Edison and his electrical inventions, but the idea behind the electrical plug belongs to a lesser known personage, a man named Harvey Hubbell.

One day in New York City, Hubbell was walking by a penny arcade when he noticed how the janitor had to detach and reattach the power supply wires for every machine in order to sweep the floor. Among other things, this involved identifying the corresponding terminal post for each wire, reconnecting, and then checking for potential short circuits.

Hubbell's solution was the electrical plug and socket, which he patented in 1904.

The problem with these early electrical plug types was that they weren't grounded, which could result in electrical shocks. Philip Labre addressed this problem in 1928 by creating the 3-prong electrical plug type while attending engineering school in Milwaukee.

An electrical plug Babel

Unfortunately, after Labre's invention, countries around the world began creating their own electrical plug types rather than settling on a global design standard. Different electrical plug types may feature vertical or horizontal pins, round pins, diagonal pins, etc.. That's why when you go on overseas trips, your small appliances won't work without an electrical plug adapter and sometimes even a transformer for converting voltage.

For the most part, the electrical plug types of the world are divided into two major geographic areas: the U.S. and Japan in one group, and South America, Europe and Asia in the other group. Africa, southern Asia, and Australia are another thing altogether, as they use a very heterogeneous mix of electrical plug types.

U.S. electrical plug types

It's true that there are about thirteen basic electrical plug types used worldwide. These electrical plug types have officially been given a letter to help differentiate one from the other.

There are 2 electrical plug types familiar to U.S. residents:

Type A: ungrounded American/Japanese 2-pin

The electrical plug type A has 2 flat parallel pins. These 2 pins used to be the same size, but on new electrical plugs the neutral contact is larger than the live contact.

Type B: grounded American 3-pin

The electrical plug type B features the same 2 parallel pins as the type A electrical plug, but also has a round grounding pin beneath these. You may have noticed on these electrical plug types that the grounding pin is longer than the flat pins. That's so the electrical plug will be grounded before it connects to the electrical supply.

Since the mid-1960s, all electrical sockets are required to accommodate this 3-pin electrical plug type design.

More information on electrical plugs