Reading the list of standard plug and socket types on Wikipedia, I see that countries have made their mains voltage higher or lower.
For example, in Mainland Britain (Wales, Scotland, England) the voltage has been lowered to 230V from 240V. On the other hand, in Northern Island it has increased from 220V to 230V.
Have they just moved the voltage to informally meet the rest of the world? As the vast majority of countries are either 230V or 120V.
Are there any other things that could be gained from this? I understand that lowering the voltage could decrease power dissipation because \$P=VI\$, but increasing the voltage? What is there to gain other than more losses?