As I've mentioned before, supplies in the U.K. at one time varied between 200 and 250V. By the early 1970s all had been standardized at 240V (415V 3-ph) with an allowable tolerance of +/- 6%.
Over in Continental Europe, most countries standardized at 220V, one or two at 230V or 240V.
In the pursuit of getting everything into a European "one size fits all" mold, the various committees decreed that all countries in the E.U. should move toward 230V (400V 3-ph) becoming the standard.
Nothing has changed here, but officially our supplies are now designated as 230V. How come?
The authorities have altered the official specification to 230V +10% / -6%. It's planned that in a couple of years the tolerance will be widened to +/-10%.
"See Mr. International Committee, we've converted all our supplies to 230V!"
Well, politically, maybe, but from a technical point of view they're still 240V +/-6%.
