Hi Tony
In the UK the actual mains voltage is NOT 230VAC, it is frequently nearer to, if not over 250 VAC.
When the UK harmonised with the EU 230VAC ?we did not change our mains voltage, just the acceptable tolerances were widened to make the UK compliant.
?
Just for clarity are we talking about the over voltage circuit that sits across C2 and C3 tripping?
?
G Edmonds