Why does the US use 110v and the UK use 220v?

Question

Why does the US use 110v and the UK use 220v?

In: Engineering

Answer 1

The UK is generally 240V – the same as the US (but US properties tend to split that into two lots of 120V).

The UK is in theory 230V, but that was a fudge to harmonise with the EU. Many places in the EU traditionally used 220V, so in 2003 they were harmonised to 230V but with a +10%/-6% tolerance, so devices in the EU (and UK) are required to work from 216V to 253V. This meant the countries that were 220V could keep their 220V supply, and those that were 240V could keep that.