Yes to harmonise with Europe some time ago our nominal 240 volts was changed to 230v plus up to 10%. I first noticed a breach of this at the boatyard that built my narrowboat at Glasson near Tamworth. Plugged boat into shore power after a cruise and the Combi invertor/charger remained taking power from batteries. Measured incoming power using DVM and saw 261 volts! Spec of Combi showed it only accepted up to 257v. Fortunately I had a backup charger more resiliant to over voltage.
Later heard that as a bodge following regular tripping from new adjacent estate, they had changed the transformer tapping!
