John Smith wrote:
One of the kitchen lights was flickering and there was noise coming from
the switch when the light was flickering. I removed the cover, preparing
to replace the switch.

Before doing anything, I first measured the voltage. The voltage between
the bottom (hot) black wire and ground was 110 V. That's what it should
be. When the switch was in the ON position, the voltage between the two
black wires was 0 V. That's what it should be. When the switch was in
the OFF position, the voltage between the top black wire and ground was
0 V. That's good.

However, when the switch was in the OFF position, the voltage between
the two black wires was between 86 and 88 V (the reading kept changing.)
This switch was in a 3 gang box. The other two switches all had 110 V
between the two black wires.

About a month ago, I had another light problem in the bed room. And the
voltage between the two black wires was also around 88 V.

Why isn't it 110 V?

Hi,
You are measuring voltage with the lamp in the socket in series.
Maybe you have bad socket(arc'd, oxidized, or tarnished or plain loose
contacts inside the socket). How old is your house? Any Al wiring?