So you don’t take the lamps out of pendants? Fluros out of circuit And still manage to get acceptable readings? Maybe I need to change my MFT??? The other thing to be aware of is most of the old thorn fittings say disconnect before insulation testing In my apprentice days I blew up a few 1970s era chokes testing an old school more modern kit doesn’t mind so much but still skews the readings quite a bitI always view the fittings as part of the circuit on a Periodic.