If you work out the permitted upper limit under the old standard (240V +/-6%) vs. the new standard (230V +10%/-6%), there's not much difference:

240V + 6% = 254.4 volts
230V +10% = 253.0 volts.

It was entirely a political exercise in juggling the figures here though, which has left us with that weird assymetric tolerance specification. (It's rumored that eventually this will be changed to 230V +/-10%).

The 250V rating on BS1363 is because it was introduced long before the standardization at 240V took place, and 250V was the highest nominal voltage then in use.

I'd agree with Dave's criticisms of BS1363. The poor contact on some fuse clips does lead to overheating. I won't use one of the cheap brand plugs on an appliance which draws a substantial current. They're fine for radios, tablelamps, etc. but when it comes to a kettle, electric heater, washing machine or something similar I'll stick to MK or some other higher-quality brand.

There's one other danger with BS1363 as anyone from the U.K. and Ireland will tell you. The plugs are darned unforgiving when you step on the upturned pins while fumbling your way out of the bedroom in semi-darkness! Ouch! [Linked Image]




[This message has been edited by pauluk (edited 08-31-2005).]