mm wrote:
On Sun, 05 Apr 2009 16:20:03 -0400, "Percival P. Cassidy"
wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.

What could cause this?

Perce

I'm going to guess here that you have
some kind of electronic switch, i.e. a
dimmer or something similar. As long as
there is enough voltage to turn on the
LEDs, a small leakage current from an
electronic switch could make them glow
dimly.