For reasons I don't want to explain, I tried to replace the light switch at work (in my office) myself. It controls two fluorescent fixtures.
Before taking the switch out I tried to measure voltages. Of course there was no neutral wire; however, between live and ground there was 279 vac (same reading with 2 different voltmeters; one of them also measured frequency, it was 60Hz).
So of course I closed it back up without trying to replace anything.
Why should there be 279v between live and ground? I should make clear that the switch was off, so as far as I know I was not measuring anything related to the coils in the fluorescent fixture.
All help appreciated.