OP
C&H
I got 400v at a 16a single phase socket one time doing a periodic. Couldn't believe my eyes, switched meter on/off a few times and the RCD, still got 400v. Socket was wired on the yellow phase, turned out flood light on the red phase had melted phase to cpc. Incoming earth had been disconnected from the HV transformer hence 400v live to earth lol. The mind boggles sometimes.
