On Oct 19, 2:01*am, Rebel1 wrote:
This apartment has strange problems. Incandescent bulbs burn out too
fast, usually when a switch is turned on. I monitored line voltage with
a plug-in meter that displays voltages in the range of 90 to 130. The
needle stays pointing in the green zone (110 to 125 volts). I don't live
there, but I left the meter there and the renter says it stays in the
green zone.

Aside from that problem, the kitchen has a ceiling fan with three light
bulbs (standard base). The bulb in one position burns out, again when
power is switched on, much more often than the other two.

I've tried using bulbs rated at 130V. Seem to give better life, but
there is still a definite problem that I can't blame on simple high
voltage. There is no flicker that could indicate that the bulb isn't
fully screwed into the socket.

This is an "illegal" apartment, which means that there can be many code
violations.

Thanks for you suggestions/comments.

R1

Over-voltage is the commonest reason.
Are there any sources of vibration? (eg Traffic)
Are there any large inductors (motors) operated in the nieghbourhood?
Also it's possible for a loose electrical connection somewhere to
cause problems.
Are the bulbs likely to be overheated by external factors or in small
enclosures?
Frequent switching reduces lifespan.
Or you could just have a bad batch of bulbs.