It is a horrible idea, even if using only theoretical
knowledge. I suspect that you have something different
in mind when you say theoretical knowledge. I'm using
it to mean the things below:
The pole feed will rarely, if ever, have equal
currents on the two hots and the neutral. If a different
design was used that did not depend on imbalance, there is
still the problem of tripping at 5 mA ground current to
protect people. One could easily have 5 mA current to
ground on one total service with no fault - and he's
talking about protecting multiple services. False trips
would be common. If the trip level was set higher, then
there could be a current at that higher level through a
person into ground. The size of the contacts would have
to be enormous to handle the current.
This would be a great example for considering all the effects of a
'safety' improvement. Has there ever been a paper, or a summary of
the field trials, published on this result? Something that said, for
example, that each year, in the USA, X people get electrocuted by
refrigerators. This could be virtually eliminated by requring GFCIs,
but then Y people would die of food poisoning, and Y>X.
Or is it considered 'obvious' that this is the case? For example,
refrigerators are usually grounded, so maybe X is near 0, and it would
certainly be an inconvenience to have a GCFI breaker trip and spoil
Basically, does anyone know of any formal study or review on this
topic? I could not find any on-line, but such a study would probably
predate the internet.
So something minor happens, and all the lights go off? THIS IS A VERY
STUPID IDEA. The code here requires separate lighting and receptacle
circuits so the room doesn't go dark if you trip a breaker. Also, most
areas of a home do not need GFCI protection. Wet areas, areas with bare
concrete floors, or outdoors make sense. Some circuits it is illegal to
use a GFCI breaker, like a refrigerator, or a freezer.
Really. If we have to ground-fault an entire house (because the occupants
are too stupid and keep getting electrocuted to death) then maybe they
should just go live in a hut somewhere in Afghanistan, where there is little
risk of electrocution? ;)
Speaking of electrocution, I got quite a nasty zap from my plasma cutter
the other day. 380VAC/20A plasma arc (open circuit), ground clamp wasn't
getting sufficient contact with rusty metal. That was with rubber soled
shoes (no steel toe), apron, and thick leather welding gloves. Anyone got a
GFCI for that baby? ;)
No, but I have a suggestion. A second ground clip, connected to a low
voltage power supply, and a relay with a low voltage, high current coil.
Then use the relay contacts to make sure that both clamps are making
good contact, the plasma cutter doesn't fire up. The second clamp
wouldn't have to be as heavy as the ground clamp, and you might even
mount them together, so you put them on the metal like they were a
I need one for my stick welder. I wont weld in the garage because I
started a fire in there once (I was able to make it out). So, I weld
outside, in front of the garage door. This is fine, except when the
ground is damp. I have gotten zapped far too many times when changing
the welding rods.
I believe most european contries have a GFI, certainly we have them in
Denmark where I live. I'm very happy we have those installed in the main
power inlet because it is a lifesafer. Many houses fail to have correct or
even installed ground/earth protection at all (before 1970 or thereabouts it
was not illegal to run appliances without earting). In these cases the GFI
serves a great purpose and which is why it was installed in the first place
I have only experience lightning strikes mistakenly triggering the GFI
two/three times over 30 years, so I see no reason to apply them only to
certain areas in the house. The only times I have been bothered by the GFI
is when I'm doing experiements in my lab, and in these cases I have been
surprised sometimes because I did something stupid (like connecting the
scope to the phone wire, tripping the GFI because the phoneline neutral is
Interesting. All of the wiring in my house when it was built in the 60's
was all non-grounded. Uses the round branch fuses... Since then a lot of the
wiring has been upgraded, but even now some outlets are not grounded
properly, and there is no GFCI's in any room. In the garage, the outlets are
grounded to a metal rod in the ground, which barely passes as a ground,
especially when cutting steel with a 380v cutter... :)
A whole-house GFCI would be a nightmare for my residence. Some drills and
other power tools out in the garage are the old metal ones, which do leak
some parasitic conductance. I'm sure if my whole house was GFCI'd, I'd have
a remote-reset for it.... :)
A ground fault is not something i would consider minor. I'd rather be
inconvinienced(sp?) by having to go to the box and reset the gfi than get
shocked by faulty equipment.
You can have a fault anywhere and on any electrical device on the house, why
limit protection ?
We have that too. Different breakers for lighting and receptacles.
More info: country is Portugal, Here we have the meter, followed by a big
breaker that is also a GFI (which we call "differential breaker") outside
the house/apartment, the differential fault current is 500mA and overcurrent
is settable from 10 to 30 Amps, according to hired power.
Then, inside the house there is the main panel with a smaller breaker/gfi
that feeds all the circuit breakers. Mine is 30mA, way too high, in my
experience. Lights and receptacles have to be on different circuits. Power
is 3 phase at least for most houses, i'm not sure about apartments.
You don't need to shut down the whole house for one fault.
In the US we have individual GFCI breakers, or outlets, so you can
protect any area without killing everything in the house. I prefer our
method. Especially when I am working out in my shop after dark. I have
trouble walking, and I would have to wait till daylight peeked into the
air vents along the roof so i could see well enough to make my way out
of a metal building with no windows.
Do you like to eat spoiled food? What happens if you are gone for a
couple days and that GFI trips? with no one home to notice, you have a
big mess to clean up, not to mention the cost of replacing all the food.
It's clear your codes are far stiffer than ours.
But part of it is we have a different approach. By making individual
GFI's near the load, we have a lower setpoint than you can have for
the whole house.
We do not, as far as I know, require separate circuits for residence
lighting & outlets; in many rooms, the only lamps plug into outlets.
Sometimes the outlets are switched. (Commercial building DO have
Virtually no residence in the US has 3-phase. Considering the US's
saturation of whole house air conditioning, we would do better if
we did. Does your home have AC/electric heat?
In general, the code required is the one in effect when the house
was wired, or last rewired. When the code changes, the house does
not; it is "grandfathered" in to the old standard. Is that true
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I like the ideia of having more GFIs but this is not usually done as they
are expensive, i think they are putting one for the bathrooms now, but i'm
not sure. Only the whole house one is mandatory.
We use mostly electric space heaters, and the electrical water heater is as
common as the gas one. However about 5 years ago the country had a network
of natural gas installed and 99% of all houses build now come pre-equiped to
use gas for central-heating.
Regarding 3 phase, I believe that the main reason is that until some 15
years ago all houses had their own well(sp?) and the water-pump motor was
always 3 phase. The evolution was: people had their fields, then electricity
came and most people got a water-pump for the field, then houses were build
on those fields, etc. But it's also a "policy" because 3 phase is more
balanced, doesn't need so heavy wiring, specially if you consider that all
the old houses had fuses, not breakers. Now i have 3x15Ax230V350W. I
would need 45A breakers and wiring otherwise, quite a difference. However in
most other aspects the code is very poor, like inspections, what's not
allowed, etc. Yours is much more detailed.
Yes, i think you can still have a wiring box with just fuses! But hey, they
did update the meters to new models a few years ago... ;-)
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