In reply to a post by therioman:

In reply to a post by eckiedoo:

Incidentally, the UK Mains Voltage remains effectively at 240 Volts; and generally in my locality runs higher around 245 to 250 Volts.

The nominal rate is 230V not 240V - and if you're doing any sort of calculations as an electrician you have to use 230V as the nominal not 240V. Our nominal rate changed in 1995 I believe offhand.

The supply you receive will vary for all kinds of reasons - for example our office has an average of 232.6V - but it is important that all calculations are done on the assumption of 230V.

You are lucky ... I have detected mine down at near 210v - out of tolerance!

I can always have a good guess at the voltage based on how long my toast takes and the colour of the elements!

Agreed that the "Normal" Voltage in the Harmonisation Rules is 230 Volts.

But if you read the Rules in detail, Europe is divided up in to three major areas-

UK and Ireland,

Western Europe

Eastern Europe.



This is to accommodate the historic and practical situation that-

240 Volts was previously their Mains Voltage - with the large installed capacity etc, which could not be changed "overnight".

230 Volts was similarly the Mains Voltage for France, (Western?) Germany, Italy Spain etc.

220 Volts was similarly the Mains Voltage was the various countries of Eastern Europe.


I also suspect that it is because of those significant differences that the applied adjective is "HARMONISATION", rather than "Standardisation".

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https://en.wikipedia.org/wiki/Mains_electricity
"
Voltage Levels
Most of Europe, Africa, Asia, Australia, New Zealand and most of South America use a supply that is within 6% of 230 V.

In the UK and Australia[3] the nominal supply voltage is 230 V +10%/−6% to accommodate the fact that most supplies are in fact still 240 V.
(Separated for clarity)

Japan, Taiwan, North America and some parts of northern South America use a voltage between 100 V and 127 V. The 230 V standard has become widespread so that 230 V equipment can be used in most parts of the world with the aid of an adapter or a change to the equipment's connection plug for the specific country.
"

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http://www.claudelyons.co.uk/energy_saving.htm
"
European Voltage Harmonisation

The United Kingdom for many years had a standardised supply voltage of 240V ±6% (415V for three-phase) whereas continental Europe had a nominal supply level of 220V (380V). From 1 January 1995 the nominal voltage across Europe has been 'harmonised' at 230V/400V.


This is not a real change, since the former 240V countries, including the UK, have in the first stage of voltage harmonisation a tolerance of 230V -6% to +10% (i.e. 216.2 - 253V) as compared with the 'old' limits of 240V ±6% (i.e. 225.6 - 254.5V). However, the former 220V countries (most of Continental Europe) have limits of 230V -10% to +6% (207 - 243.8V).
The Electricity Safety, Quality and Continuity Regulations 2002, which came into force on the 31st January 2003, replacing The Electricity Supply Regulations 1998, formally confirm the UK standardised supply voltage tolerances at 230V -6% to +10%. DECC, the Department for Energy and Climate Change has confirmed that this remains the UK position but is currently (April 2010) under review for a possible change to 230V ±10% in 2011.


Plans to harmonise the whole of Europe to 230V ±10% (i.e. 207 - 253V), which were due to be applied from 1st January 2003, were first postponed until 1st January 2008 and are now postponed indefinitely pending a consensus between the various parties. Despite this postponement, any equipment intended for use anywhere in Europe and carrying the 'CE' mark will have to be capable of working over this wide range.
"
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Regarding low voltages, i ahave seen the UK Mains Voltage down at about 190 Volts for several hours and days - but that was a way back in about 1953.