On Wed, 9 May 2007 09:19:05 -0300, "John Gilmer"
wrote:



Why should switching power to a GFI trip it? A GFI works on difference
on current flowing in 2 parts of the circuit. Both are being started
and stopped at exactly the same time.

My holiday light setup involved a GFI that was switched like that, I
used if for about 40 days, and had not one trip that occurred when it
was being switched.


Quite correct.

BUT a un-powered GFCI can permit some safe hazards to continue.

It is better to have the GFCI always powered and have the switch AFTER the
GFCI.

A powered GFCI will detect and "trip" a "fault" between neutral and ground.

A GFCI will NOT detect incorrect wiring whereby neutral and HOT are
switched. But a powered up GFCI will still trip when either of the two
load wires have a 5ma path to ground.


I wired them that way, so the GFCI would also be a switched
receptacle. The other way (switch after GFCI) would require adding a
second receptacle.

A further advantage of putting the GFCI before the switch is that it will be
indoors and less subject to contamination from aerosols.

Regardless, it's a GOOD idea to TEST the devices. They DO fail and outside
units fail more often. And they don't necessarily fail "safe."


Why assume it's outside? My switch and GFCI were both inside.
--
Mark Lloyd
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