514.10 Warning notice: voltage
514.10.1 Every item of equipment or enclosure within which a nominal voltage exceeding 230 volts to earth
exists and
He's working on methods of controls for heating systems that operate at 230v.
there is no such thing as "Nominal voltage exceeding 230Volt"
Jesus, make up your mind.
Try reading the Reg you quoted,
If there is no such thing why does the Reg exist.
I think you need to educate yourself rather than insult others, Do you actually know what Nominal voltage to Earth is, even if he was fitting them on 400V 3 phase panels, even then your quoted Reg would not apply.