Shocked by the coffee maker. GFCI didn't trip. Normal?

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Old 04-05-17, 07:37 AM
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Shocked by the coffee maker. GFCI didn't trip. Normal?

Coffee pot wasn't directly aligned under the filter and made a big mess. Counter was covered in coffee. When I went to mop it up and touched the wet counter it gave be a fairly decent mains voltage like electric shock. I unplugged the pot, got it cleaned up and was wondering, isn't this the whole point of GFCI breakers? So I pushed the test button on the corresponding device and it tripped immediately. And for good measure I stuck a piece of wire in a kitchen outlet and touched the other end to the stove, again the GFCI breaker immediately tripped with barely a spark.

So was it just the shock that I got from the wet counter too little to trip it? Was a circuit being completed somehow so that the gfci wouldn't sense it? Should I stop buying my coffee pots at the 99c store?
 
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Old 04-05-17, 09:00 AM
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In the U.S. GFCI devices for personnel protection trip at 4 to 6 mA. You could have had a leakage, but not enough to trip the GFCI device.
 
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Old 04-05-17, 01:57 PM
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Hi Esand1,
A shock requires two contact points and to trip that GFCI one would need to be the hot side of that circuit.
Now, what else were you touching? I'm grasping at straws but could something else be hot and the coffee on the counter was just providing the ground? Appliances like a dishwasher may not be on a GFCI.

The shock was real and I agree with you, I would have expected the GFCI to trip if that was the source of the voltage. What else was in that coffee bath.

BTW, I'm famous for those coffee spills for many different reasons.

Bud
 
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Old 04-05-17, 02:17 PM
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touched the other end to the stove, again the GFCI breaker immediately tripped with barely a spark.
You did this after your shock experience, expecting a different scenario??? Luckily you had one, but gee, you gotta think about these things before you just do them. We don't know how your GFCI set up is made, since you are not in the US.
 
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Old 04-05-17, 07:26 PM
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Chandler: Possible not the smartest thing I've done but I had read that occasionally the test buttons will give false negatives.

Bud:

I wasn't touching anything else although I was barefoot on the tile floor and the counter top is marble neither of which are great conductors right? The coffee maker was the only thing plugged in which got wet but every electrical circuit in the kitchen is GFCI protected anyways.

The device is this one:



I seems to clearly say 30ma, does that mean it would let me feel 5-8 times the voltage as what you'd expect in the US? Still if I was a ground path wouldn't I get the full brunt of the coffee maker (6 amps or so) and trip it?
 
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Old 04-06-17, 12:46 AM
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I seems to clearly say 30ma
Not sure of your location, but in North America there are two classes of GFCI circuit breaker. Class A GFCI breakers are rated to trip at 5mA and are called "life-protection" GFCI's. Class B GFCI breakers are rated to trip at 30mA and are called "equipment-protection" GFCI's. Not sure if it's the same for IEC-rated equipment, but I suspect that it is.

Cheers,
Brian
 
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Old 04-06-17, 01:59 AM
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Thanks Brian, I never knew there were 2 different classes of GFCI's, probably why I have often struggled with GFCI when using tools at different job sites. I happen to have several that we swapped out thinking they were defective.

Esand1, sounds like your GFCI's "I seems to clearly say 30ma" are the higher rated so may actually have given you a bit more of a shock without tripping. I've never live tested any but have accidentally tripped some and they seemed very sensitive, possibly the Class A Brian mentioned.

Bud
 
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Old 04-06-17, 08:42 AM
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https://www.ebmedicine.net/spaw/uplo...20Strenths.png

30mA is not a good threshold for GFI protection in a kitchen or bath or any other wet areas. Especially when pushed by 230V.Name:  Physiologic Effects ASsociated With Various Electric Current Strenths.png
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Old 04-06-17, 10:16 AM
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telecom guy-

That's pretty interesting. Here (Argentina) one of the few strictly adhered to parts of the electrical code is that every household circuit regardless of use or location has to be protected by a 30ma gfi. Based on that table it seems like 30 was an odd number to choose. (in fact a quick check online doesn't even show anything other than 30ma for sale)

But a quick glance at wikipedia it seems like it's an incredibly common number with a lot of countries setting that as a standard.


Is this the answer to the thread though? That coffee pot was leaking just enough current to give me a shock but not enough to trip. It seems like it shouldn't leak any current at all, should I toss it? It has a 3 pronged outlet (even though it seems to be totally plastic), isn't the point of a grounded connection to prevent these kind of things?

Here's a possibly dumb question: Do transformers retain any kind of current after they're disconnected? Nothing else on the counter was plugged in but the spilled coffee did get to the unplugged 1kw 220 -> 110 transformer that I use for my coffee grinder.
 
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Old 04-06-17, 12:04 PM
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I take it this coffee maker is ungrounded.

Before you use it again, test using an AC current meter, from metal case to an earth ground. Test it with the plug one way then the other, if that is possible. It is definately suspect, and although it could have dried out and become safe, there is no assurance it could not happed again.

Anything over 2mA of leakage I would call it bad. There are special R/C networks for doing this per a standard, but maybe not necessary for your one test.

Also: are there point of use GFCI available there to trip at less than 5mA?

On the transformers: they become dead almost instantly after power is removed.

edit: i see now your reply of 3 prong plug and plastic body. Do you think the coffee water got high enough into the machine base to get inside? If so, I can see how the entire puddle could be hot.
 

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Old 04-06-17, 12:10 PM
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The coffee maker is both made of plastic and provisioned with a grounded plug!

I'll try to test it. I'm guessing there is a metal coil underneath to heat the water

As for the 5ma. Never seen one. Pool filter pump where you would really expect one if anywhere is just on a 30ma protected circuit.
 
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Old 04-06-17, 05:18 PM
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That's pretty interesting. Here (Argentina) one of the few strictly adhered to parts of the electrical code is that every household circuit regardless of use or location has to be protected by a 30ma gfi. Based on that table it seems like 30 was an odd number to choose. (in fact a quick check online doesn't even show anything other than 30ma for sale)

But a quick glance at wikipedia it seems like it's an incredibly common number with a lot of countries setting that as a standard.
Is that GFCI also a main disconnect switch for the whole house?

That is how it was in South Korea as well with 30mA current sensing. If I remember correctly, now their current standard is to have GFCI on each circuit and just a regular breaker for the main.

The reason for not using 5mA as in the US is because that will be rated too low for whole house or circuits for general purpose outlets. There will be too many false positive trips, especially with high current motor loads.

In the US, GFCI protected circuits usually dedicated circuits for wet locations.
I don't know how it is in Argentina, but in Korea there are generally only 4 to 5 circuits and no dedicated circuits for each appliance like in the US.
Also, there were no ground in older buildings. I believe it was only about 20 years that ground became a requirement. GFCI cannot replace ground, but far safer than without both.

Momentary 30mA is enough to kill people with some illness (such as a heart problem). But most people will survive.
 
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Old 04-06-17, 07:42 PM
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Is that GFCI also a main disconnect switch for the whole house?

That is how it was in South Korea as well with 30mA current sensing.
That is the case in a lot of smaller apartments although it is not my case. I have 3 in one panel, each protecting 2 circuits and 1 in a other protecting 8 circuits.

Back to the shock: What I don't understand is if there was some sort of ground fault which let me get shocked, why was it less than 30ma? I'm not an expert on electricity by any means but I know that electricity travels along the path of least resistance. If that is through the coffee, through me , to the ground why wouldn't it be all the current? Why just a little?
 
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Old 04-06-17, 07:50 PM
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Momentary 30mA is enough to kill people with some illness (such as a heart problem). But most people will survive.
Actually the path the current takes through the body is more the deciding factor in whether or not a shock is fatal. 30mA across the heart is more than enough to cause vFib. But a hand-to-hand circuit is much more likely to be fatal than a hand-to-foot circuit with any given current. That's why electricians keep a hand in their pocket when dealing with potentially live circuits - current can't go through the other hand if it's not touching anything.
 
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Old 04-06-17, 07:55 PM
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I'm not an expert on electricity by any means but I know that electricity travels along the path of least resistance. If that is through the coffee, through me , to the ground why wouldn't it be all the current? Why just a little?
Your body has resistance, as do the coffee, and the flooring material, and the rest of the building material. At 230v, it only takes 766 ohms of resistance to limit the current to 30mA. The combined resistance was likely much higher than that, meaning there was less current flowing.
 
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Old 04-09-17, 05:18 PM
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30mA is not a good threshold for GFI protection in a kitchen or bath or any other wet areas.
Very true, that's why in the USA 30 mA GFCIs are for equipment protection such as heat tracing piping and the 4-6 mA devices are for personnel protection.

I seems to clearly say 30ma,
It also says 40A. Is your coffee maker on a 40 amp circuit?
 
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Old 04-09-17, 05:51 PM
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It also says 40A. Is your coffee maker on a 40 amp circuit?
Uh. No. The 40A is his main, which provides 30mA GFCI protection to the whole panel. The one next to it (labeled "cocina", or "kitchen" in Spanish) is a standard 16A branch.
 
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