Electronic – What have countries gained by increasing/decreasing mains voltage by 10V

mains

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?

Best Answer

It is to standardise everything on a single fixed voltage. But in practice, mains voltage isn't 230V. It is standardised at 230V +10% -6%, or 216V to 253V. Here, mains voltage measures 249V, which is on the high end of the scale - but we're on a small farm road with not many other customers. Away from home I have measured it at 233V, due to resistive losses from greater demand. Countries have not changed the actual voltage - that would require changing all the generators or all the transformers in the country (at a substantial cost), merely, the allowable range has changed.