>GFIs work by comparing the currents in the two "legs" of the
 >circuit. They have ground connections, but don't use them
 >for their own purposes. For around the last ten years they were
 >LEGAL to install with the ground TOTALLY Missing.
 >(You MUST attach one if one exists, or can be reasonably reached.)

  I am a Licensed California General Contractor who started out as an
electrician. I have installed GFCIs in both receptacles and as  service
panel  breakers. A GFCI will not work without a ground and I am unaware
that can be installed without a ground and be in compliance with
code.....at least in my county..... in the state of California,   I have
had my wiring jobs  inspected many times and I can assure you that
inspectors are particularly interested in the ground.

 >In a recent post, I mentioned how a GFI will do almost no good
 >in protecting a Computer.  (That is what I tried to say.)
 >They burn up easy when lightning hits anywhere around, but
 >that same strike will "fry" almost anything in the house so I can't
 >call that "protection".

  I have repaired an actual lightening strike where the service panel
circuit breaker burned up  and fused open and allowed the current to
continue down the circuit until the GFCI which was installed  in a outlet
in a garage stopped it....protecting the washer and dryer from damage.

Yes GFCIs can be annoying because they do tend to trip when  heavy duty
devices start to pull a lot of amps on startup...this is why construction
crews don't like them .... they are are required for construction sites
temporary power panels ....but they have gotten a lot better in the last
twenty five years and this is now rarely a problem in a residential
environment.

GFCIs will also protect equipment in the event of a short in as much as ANY
leak to ground will be instantly detected triggering the breaker. GFCIs
trip in a fraction of a second... a lot faster then your service panel
breaker.....they were first used in pool and spa lights where they had to
trip fast in order to protect somebody swimming in water. This was before
the common use of 12 volt pool lighting. GFCIs are required by code in
bathrooms, garages., and outside outlets. And I belive should be installed
anywhere you can be working with water.

A GFCI can help protect a PC ....not only from a lightening strikes but
also from massive surges from the power company......like if the wind
knocks a tree over on to power lines.....a scenario i have witnessed
.  Again the service panel breaker was not fast enough to stop the surge
but the GFCI tripped and protected the computer equipment  that happened to
be plugged into the circuit.

If the system is wired correctly, in the event of a short the receptacle
installed GFCI breaker....which also functions as a regular 15 or 20 amp
breaker...... will trip a LOT faster then your service panel breaker.  This
additional speed may well save your computer equipment in the event
something goes wrong in the line or from external sources.

A 15amp GFCI receptacle can be had for as little as 10 bucks...which is not
a bad investment for any circuit. It is better to have your 10 dollar GFCI
burn up then your 200 dollar UPS. I personally have my UPS plugged into a
15 amp GFCI.

m

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