R2 test on a ring main where the conduit is the earth

[Engineer54]

Woe betide you if you forgot to put it on charge at the end of the day!
God help you if Jim the tester’s mate found you’d got dirt on the polished wooden case! The ones we had wouldn’t have looked out of place on mother’s sideboard.

Many of these conduit testers were mains powered units, in fact i can't say that i've used a battery unit myself... lol!! But your right about those older wooden boxed units, works of art they were!!...lol!!