GFCI Failures + Gadgets

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w_tom wrote:

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.

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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 your food.
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.
Thanks, Lou Scheffer
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I know of a study done , I put a gfi on my frige it blew, I took it off, study done.
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Lou Scheffer wrote:

Have you seen a new refrigerator or freezer without a grounded cord in the last 20 years? The metal skin is grounded unless the power cord is damaged, or the wiring is bad.
--
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Michael A. Terrell
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Lou Scheffer wrote:

The National Electrical Code requires the metal case of refrigerators and freezers to be grounded, rendering the issue you raise meaningless.
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On Mon, 17 Nov 2003 02:47:00 -0600, snipped-for-privacy@mister.com wrote:

It would be incpnvenient to wait for the Poco to reset it. The best thing would be a whole house GFCI, as is oftern used in most of the rest of the world.
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Gary Tait wrote:

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.
--


Michael A. Terrell
Central Florida
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In wrote:

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? ;)
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In wrote:

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? ;)
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Mark Jones wrote:

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 single clamp.
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Michael A. Terrell
Central Florida
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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.
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"Mark Jones" <127.0.0.1> wrote in message wrote:

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 grounded also)
Cheers
Klaus
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In wrote:

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.... :)
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What the HELL kind of monster are you building in there?!?!?!
You know, a riot, is a terrible thing, but I think it's about time that we had one!!!
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Michael A. Terrell wrote:

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.

Why?
--
Steve Sous



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Steve Sousa wrote:

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.
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Michael A. Terrell
Central Florida
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On Tue, 18 Nov 2003 02:46:18 -0000, the renowned "Steve Sousa"

I'd guess they did a study and concluded that more people would die of food poisoning than would be saved from electrocution.
Best regards, Spehro Pefhany
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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 separate circuits.)
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 there?
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David Lesher wrote:
Hi:

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... ;-)
--
Steve Sousa



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Whole house GFI? Where is this "rest of the world"? GFI'ing a whole house would be stupid.
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