3 ms·
This is my favourite story about standardization. It used to be the continent used 220V, and the UK used 240V, until we standardized on 230V. The UK defines t
by soneil 3y ago
This is my favourite story about standardization.
It used to be the continent used 220V, and the UK used 240V, until we standardized on 230V.
The UK defines this as 230V -6% +10% (i.e. 216.2V – 253.0V), and nominal supply is 240V
The continent defines this as 230V -10% +6% (i.e. 207.0V - 243.8V), and nominal supply is 220 or 230 by region.
We called this harmonisation - in reality it's more like agreeing to disagree. We just fudged the tolerances until everyone was happy.
(To put some context around this - most sites don't receive nominal supply. The actual voltage delivered depends on your distance to the local substation. Typically they over-deliver such that sites closest are a little over, sites furthest are a little under. If they actually delivered ±0%, sites at the edge of their network would be further from nominal. So end-user equipment should be built to expect variation.)
- thrdbndndn 3y ago230V±6% should be enough for both though, right?
- soneil 3y agoThat'd give an upper bound of 243.8, which is far too close to 240 to be practical. As I tried to add, there is some necessary and natural deviation from nominal to account for path loss etc. 230±6% only allows 240 to deviate by 1.5%, which isn't much scope at all. I believe ±10% was the traditional definition, so they just trimmed a little off the top end so it strayed less from Europe's definition - but not enough to actually affect nominal distribution.