Thanks for the pic Mike -- I thought it would look something like that.

On the assymetric voltage tolerances, it sounds as though you're doing a similar fiddle down under as has happened here to accommodate a standardized nominal supply voltage.

Ever since the U.K. standardized on 240V our allowable tolerance was +/-6%. The change to 230V +10%/-6% was just to comply with the new European 230V standard without actually changing anything!

Check the figures:

240V +/-6% gives a range of 225.6 to 254.4V.
230V +10%/-6% equates to 216.2 to 253V.

Unless a current 240V supply is more than 5.4% over nominal (very rare in my experience) it still lies within the permitted new tolerance.

As C-H pointed out, Sweden has gone from 220 to 230V nominal by adopting 6 and 10% in reverse:

220 +/-6% ---> 206.8 to 233.2V
230 +6%/-10% ---> 207.0 to 243.8V

I've seen references which indicates CENELEC will move to a specification of 230V +/-10% eventually. If so, then why did we not just adopt that straight away, as it's a wider tolerance than our existing specification? [Linked Image]


[This message has been edited by pauluk (edited 08-30-2004).]