In addition to the varying socket standards found around the world, different technology and electronics require varied equipment. This can result in a lot of variables and there is no single one size fits all approach.
There are many different plug types for multiple reasons, but it is primarily due to the varying speeds with which different nations first set up their own domestic power grids.
Why are there So Many Different Socket Types Today?
When mains electricity first started to be wired into domestic properties, it was largely used solely for lighting. However, as the use of electrical devices and appliances began to spread, power for lights was often cheaper than power for appliances, so many lower-wattage devices were adapted for use in light fixtures. Further rapid growth in the popularity of electrical appliances then meant that many more devices began to feature dedicated mains plugs and sockets.
The US initially led the way in standardising pin-based appliance plugs for wall sockets, quickly followed by Europe and Asia. However, most countries rejected the early North American standard of 60Hz, 110V power and their corresponding, less secure two-pin plugs.
Instead, alternative designs were used which often included higher voltages for more efficient power transmission and plugs with ground pins attached. For instance, the UK eventually settled on three-pin plugs featuring a built-in safety fuse.
Various plans to introduce a universal system have since been considered but there are currently no plans to move towards a single international standard. This leaves us where we are today, with a wide array of international plugs with usage varying by country.