I thought the GFI was supposed to trip ?????

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I just went to an auction and came home with a whole bunch of old junk. One of them was an old metal framed swivel house fan. I am always leary of that old stuff, so I always test it in a GFI outlet.
I plugged it in, and reached to flip the metal switch. When I touched it, I got a fairly good jolt on my fingers. The GFI did NOT trip. WHY? I thought that was the whole purpose of having them. This GFI was just purchased and installed, and the test button works fine.
Just for the heck of it, I plugged the fan in again, and had the switch already turned on. The fan ran just fine on a wooden table. Then I set it on the cement garage floor and plugged it in again, and the GFI tripped instantly. For the heck of it, I put a piece of wood under it (on the floor) and the GFI did not trip. This proves that fan motor has leakage to the metal housing, so it goes in the garbage. But I can not understand why the GFI did not trip when my fingers got shocked ????
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On Wed, 29 Nov 2006 00:22:47 -0600, snipped-for-privacy@UNLISTED.com wrote:

Evidently the current flow through the fan to your hand, through your body, throught your shoes to the ground was below the threshold of the GFI. That path presented enough resistance to current flow to limit it to a small enough value that the GFI didn't trip. Placing the fan on the floor provided a lower resistance path so he current was high enough to trip the GFI.
GFI's will allow a small amount of fault current to flow without tripping. This reduces nuisance tripping, but still provides protection against dangerous levels of current. There was enough current to feel (which is very little) but not enough to be dangerous.
Seems like the GFI did its job, and you were smart to do the test you did.
Paul
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snipped-for-privacy@UNLISTED.com wrote:

head to home despot or lowesers (or better yet a local place) and purchase a little outlet tester.
3 lights indicate the wiring, and a button tests GFCIs. Much better for testing GFCIs than the test button on the outlet.
Also, GFCI breakers are much more sensitive (and faster) than GFCI outlets. I converted a circuit from GFCI outlet to GFCI breaker, just for fun I tested the GFCI outlet on the circuit with the GFCI breaker. Breaker was faster than the outlet.
Dave
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snipped-for-privacy@yahoo.com wrote:

The test you did doesn't prove GFCI breakers are more sensitive and faster than GFCI outlets. It just proves that the particular pair you had behaved that way.
To the OP, what were you standing on, type of shoes, etc or in contact with when you got the shock? It does seem that the current you got was less than the amount needed to trip the GFCI.
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I would open up the fan and check to see that the metal casing is actually grounded. Sounds like it's not. It should be.
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snipped-for-privacy@gmail.com wrote:

Since it's an old swivel type house fan, it's unlikely it has a grounded cord to begin with. Also, even if it does, you can verify that the case is grounded with a VOM, without taking it apart.
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On 29 Nov 2006 07:24:10 -0800, snipped-for-privacy@optonline.net wrote:

The first way to check if the case is grounded is by looking at the plug. It has to have 3 prongs to be grounded.
If it is a two prong plug, and it sounds like that is what it is, It will not be grounded.
This was a problem. Most likely you can flip the plug in the receptacle and the "shock" will go away.
The hot is connected to the case in one situation and connected to the switch for the motor lead in the other.
They came out with polarized plugs to assure that the hot is connected to the load first.
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Terry wrote:

Good grief! If that were true, don;'t you think there would be an awful lot of people dead from decades ago? I don;t know of any appliances with a metal case, where if you simply plugged the cord in one way vs the other, you could wind up dead, because the case is now hot.

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On 29 Nov 2006 11:01:28 -0800, snipped-for-privacy@optonline.net wrote:

There were more electricution deaths in the past. Much of that old stuff was more dangerous than the newer stuff. I cant begin to count the number of times I got shocked when I was younger (in the 60's and 70's). Most of the time people are not killed, just shocked.... It was leakage, not direct short in most instances...... Those old metal encased power tools, as well as "hot chassis" radios and tvs were the worst. I'd say the most shocks I got when I was younger were from the old metal electric drills. Now they are plastic cased, have 3 prong plugs or polarized plugs. Much safer.... Electricity is much safer these days.
I had an old tube type short wave radio when I was a kid. I ran a long wire out the house to garage for an antenna. That radio had a "hot chassis" In other words, if the plug was in one way, the chassis was direct to the 120VAC. If reversed, it was hooked to the neutral. So one day I had it turned on and connected the antenna wire, then was going to connect the ground wire (shortwave antennas need a ground). As I connected this ground wire, the thin wire literally burned off the insulation and left a nasty burn on my hand. The house filled with smoke and my dad got really pissed and was going to throw the radio away. After he calmed down he called his brother (my uncle), who was an electrician. He installed a polarized grounded plug on my radio, and we never had another problem with it. The days of having to reverse the plug are no longer an issue.

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Terry wrote:
<snip>

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On 29 Nov 2006 07:15:42 -0800, snipped-for-privacy@gmail.com wrote:

It's NOT. This is probably a 1940's or 50's fan. No ground wire to the outlet. Just the old 2 prong plugs which is all that was used on that old stuff. When I get a box of stuff at those auctions for a couple bucks, I dont waste too much time fixing the bad stuff unless it's really valuable. I really did not need another fan anyhow, but there were lots of other goodies in the box. I always test all the stuff as soon as I get home and discard the bad stuff so it's not laying around.
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snipped-for-privacy@optonline.net wrote:

Yes, the test I did was anecdotal, but GFCI breakers are more sensitive.
D
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snipped-for-privacy@yahoo.com wrote:

Do you happen to know whether this is by design or is it just "always that way"?
And if by design, why?
I wouldn't think it would be difficult for the designers to set roughly equal sensing levels/times in both types.
Jeff
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Jeff Wisnia wrote:

I have to claim 'just in my experience' based on a few cases, I did read something awhile ago and can't find the darn thing.
One common sense reason to claim the breaker 'more sensitive' though is that the breaker will 'see' more wiring and equipment, and so the background leakage the breaker sees will be higher than that which an outlet will see (even if chained to a few more outlets).
Since the background leakage will be higher, the amount of fault current required to hit the magic number of total leakage current (usually 4-6mA) will be less.
Dave
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snipped-for-privacy@yahoo.com wrote:

Makes sense to me...I've encountered more than enough cases of GFCI breakers tripping because of cruddy conditions along the circuit to become an advocate of just using GFCI outlets.

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Jeffry Wisnia
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On 29 Nov 2006 06:58:59 -0800, snipped-for-privacy@optonline.net wrote:

Cement garage floor, leather shoes that were somewhat wet from walking to the garage after a rain storm. I ONLY felt the shock on my fingers. I was not touching anything with my other hand or other body parts.
Mark
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Two-prong plug on the fan, right?
The amount of current on the hot line is the same as that on the neutral. So as far as the GFI is concerned, there's no ground fault. It can't tell if it's just the fan motor between hot and neutral, or the fan motor and you.

The cement floor provided a current path to ground, so the amount of current on the neutral was different from what was on the hot. The GFI sees that difference and trips.
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Warren Block * Rapid City, South Dakota * USA

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Warren Block wrote:

Irrelevant.
The current through his body returns to ground (just like the garage floor test that follows), not neutral.

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CJT wrote:

Certainly seems that the current through the GFCI should be unbalanced. The only way it would be possibile for it to be equal would be if you grabbed one part of the fan that was shorted to hot, and another that was connected to neutral.

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Pretty clearly not the case since the GFI didn't trip. Unless it's faulty. Or are you saying it's impossible to get shocked between hot and neutral?
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Warren Block * Rapid City, South Dakota * USA

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