He's just making up stories, the UK has strict regulations on 3-ph wiring
to
prevent a single phase appliance being exposed to more than one phase.

You have to watch out though, some of PHucker's fairy tales are vaguely
plausible!

Regulations don't stop accidents or idiots. My neighbor down the road had
her appliances fried because of a power co. employee screwup. They happily
replaced her appliances and everyone was very glad she didn't get
electrocuted or had her house burn down. Stuff happens.