I'm in the US. While repairing a light fitting I noticed that with the breaker on I was seeing only 30V AC, instead of the expected 120-ish. However, the now-repaired light fitting is working as expected. Why would I see only 30V?
Possibly relevant details:
- I read the 30V unloaded -- i.e. my voltmeter probes across the two mains wires coming out of the ceiling, with no connection yet made to the fixture
That probably renders the remaining points irrelevant -- esp. 3 and 4 -- but here they are anyway;
- The fixture is on the same circuit as our garage lights, as well as some lights in the main part of the house. (It's in our utility room, where our washer and dryer are.)
- It's a common-or-garden T12 dual tube fluorescent deal, with ballast.†
- It's dual-switched -- i.e. a switch at the door into the house, and one at the door into the garage.
† For anyone who read the earlier question, I ended up just going back to a ballast set up this time.