Bernard Cleyet said, "Here any bath
outlets must be powered with ground
fault interrupters. I doubt a
similar safety device can be
designed for lamps, so an insulated
switch is an excellent idea."
Actually GFCIs can easily be used on
lamps, including built-in lamp fixtures.
If the GFCI is in the circuit-breaker
box, everything on that circuit
is protected, including lamps.
If the GFCIs are at the outlet (rather
than at the circuit-breaker box), the
wiring to the ceiling light, make-up
lights, medicine cabinet lights, etc.
can be wired from the GFCI outlet. This
is what I did in my bathroom. One circuit
from the circuit-breaker box powers the
whole bathroom. The first place it goes
is a GFCI outlet. After the outlet
it goes to a couple other outlets,
plus the ceiling light, plus the light
over the mirror, plus the exhaust fan.
Hence, everything in the bathroom is
GFCI protected from one GFCI outlet.
There is an important thing to realize
about GFCI protection. It does not protect
you if you insert yourself between the hot
and neutral wires. For example, if you stick
a paper clip into one slot with one hand
and another paper clip into the other slot
with your other hand, the GFCI won't detect
any problem. The current going out of the
hot, through you, and back to neutral, will
be just what the GFCI expects. Unless,
interestingly, you are also grounded at some
other point on your body so that several
milliamps will go there instead of into
the neutral.
Therefore, if your lamp is plugged into
a GFCI outlet, and you change the bulb
while the lamp is plugged in and the switch
is turned on, the GFCI will not protect you
if you touch both the socket threads and also
the contact at the bottom of the socket. It
will protect you if you touch the live socket
tab and some other grounded object such
as a radiator.
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton College
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu