Electric Cooker simmerstat Life

That voltage was too high. Most Irish supplies sit between 220-230V, the original spec here having been 220V, more like continental Europe.

That being said, your Belling Cooker is very likely to have been designed for British use. Their old spec was 240V, now nominally 230V, but it wouldn't have been entirely unusual to have had power coming in at over 240V, so it would seem unlikely that your cooker would have been too upset by that level of voltage.

Most old British appliances like cookers are 220V / 240V spec, so it covered export markets, notably here. You often saw the different wattage outputs tabled for running on 220V too.

Everything's now nominally 230V.

Seems Northern Ireland may have actually moved to 230V long before the UK in general did. I've seen old NI meters with 230V 50Hz and they seem to date from the 1960s/70s.

Also saw a very, very old ESB one with 210V 50Hz. I remember reading somewhere that there were a few lower than 220V supply areas in the ESB's network, which included the Phoenix Park.

Bit of a history lesson:

220V / 380V 50Hz seems to have emerged sometime in the very early days of European systems and was popular in Scandinavia and parts of Germany. It’s likely originated from Siemens, AEG, ASEA & Brown Boveri.

ESB seems to have just picked what was the most open standard of that era, which was 220V / 380V at 50Hz

Britain used a vast array of voltages ranging from 200 to 250 as well as DC supplies. They finally settled on 240V 50Hz, only officially in the early 1970s. Before that it was quite regionalised. It also had no official mandatory plug type - there were about 6 different round pins and various other odd designs. That’s likely why the ESB preferred “Schuko” originally - it was an actual system and it went very well with 220V.

France, Italy and Spain and a lot of places electrified by French, Italian and Spanish companies used 127V / 220V 50Hz systems, which had two lives and a neural, very similar to the US Edison approach. This system cropped up in various random spots around Europe too. Often you had two meters, one for light (127V) and one for power (220V). The light was cheaper because they had to compete with gas lighting.

In the aftermath of WWII and the early days of standards development in Europe, the predecessors of CENELEC picked 220V 50Hz, the most common system and the 127V split phase system was eliminated. So the entire continent was on 220V/380 50Hz.

In a lot of cases you could just connect the two lives to a socket and get 220V from phase to phase, so conversion was easy and as time went on 220V + grounded 0V neural replaced those. (Also a reason why polarity on continental plugs is irrelevant).

Britain, Cyprus, Malta, Australia, New Zealand and several places heavily influenced by UK standards had 240V/415 50Hz

Most appliances were happy on 220-240V, there were exceptions, but to make appliance sales easier in Europe, and with the approaching single market in the early 1990s, CENELEC split the difference and moved to 230V/400V 50Hz by expanding the margins slightly to accommodate 220 or 240V systems. The networks have, as things are replaced moved target voltages to 230V/400V too and ultimately the voltage range accepted on supplies will be narrowed again.

Then the IEC officially adopted the same 230V/400V recommendation, making life a lot easier for consumers and equipment makers world wide in countries using the European style supply systems. So this is now also the norm in Australia etc etc

and that’s how we got to 230V!!