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GFCI protection


kurt
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At Corey's seminar, he showed how a blow dryer tossed into a bubble tub doesn't necessarily trip. In fact, in most cases, it won't trip. He tossed a line voltage blower dryer into a "tub" over and over, and it didn't trip.

Anyone know why? (hint.....the modern tub doesn't have the thing necessary to make it trip.)

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That's exactly it. Plastic tubs, plastic pipe. No continuity, no ground.

Toss in a wire attached to anything conductive, it trips.

.....Conductive and connected to a return path of any kind that bypasses the GFCI device. That way, the currents in the supply and return conductors within the device are no longer the same, because a portion of the return current is taking an alternate, external route that the device does not sense. That's what it's internal circuitry looks for, a mismatch.

Marc

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OK, if you place your hand and a blow dryer into a sink with water it will trip correct?

Not necessarily. It depends on:

1) The conductivity of the particular sample of water in the sink.

2) How well your body is grounded.

3) How well the water in the sink is grounded.

4) The presence of other grounding paths, including the neutral conductor in the hair dryer.

5) The trip threshold of the GFCI device.

Marc

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So what's the fix, install bonding straps at plastic fixtures? Oh I know, don't submerge an electric appliance, especially when it's plugged in!

GFCIs were intended to prevent tragic accidents, they can't do much to prevent stupid. I know it's not a real popular stance in this profession, but I'm all for a little natural selection.

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So what's the fix, install bonding straps at plastic fixtures? Oh I know, don't submerge an electric appliance, especially when it's plugged in!

GFCIs were intended to prevent tragic accidents, they can't do much to prevent stupid. I know it's not a real popular stance in this profession, but I'm all for a little natural selection.

If you are not grounded, even the blow dryer in the tub should not hurt you... (not that I would test the theory personally!) Kind of like the video of the helicopter servicing the high voltage power lines, the killer comes if you touch both the line and ground or the other phase at the same time.

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That's exactly it. Plastic tubs, plastic pipe. No continuity, no ground.

Toss in a wire attached to anything conductive, it trips.

Cool - Maybe I'll update my avitar to a smarter looking fellow. [:-graduat

Ohhhh....so that's not your picture after all?[;)]

Marc

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So what's the fix, install bonding straps at plastic fixtures? Oh I know, don't submerge an electric appliance, especially when it's plugged in!

GFCIs were intended to prevent tragic accidents, they can't do much to prevent stupid. I know it's not a real popular stance in this profession, but I'm all for a little natural selection.

If you are not grounded, even the blow dryer in the tub should not hurt you... (not that I would test the theory personally!) Kind of like the video of the helicopter servicing the high voltage power lines, the killer comes if you touch both the line and ground or the other phase at the same time.

Voltage gradients produced by current flow in the water may shock that portion of your hand that is submerged.

Fresh water voltage gradients

Marc

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I was told that you will get a shock but it "should" not be lethal!

I just can't help to recall my days working on my in-laws ranch. We had a little device that was called a "Hotshot" imagine an electric fence on a 4' stick! They raised mostly cattle, but also had a few hogs that they kept for the grandkids, and eventually for the Easter dinner! One day I had the job of moving the hogs from pen A to pen B! On old sow would not move so I hit her with the Hotshot. She fell over dead! I killed a 700lb pig with a Hotshot! Later I was told by one of the "paid" ranch hands that Hotshots have a warning on them not to use with swine!

Anyway, it goes to show you that it does not take much to shock the hell out of ya!

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I was told that you will get a shock but it "should" not be lethal!

I just can't help to recall my days working on my in-laws ranch. We had a little device that was called a "Hotshot" imagine an electric fence on a 4' stick! They raised mostly cattle, but also had a few hogs that they kept for the grandkids, and eventually for the Easter dinner! One day I had the job of moving the hogs from pen A to pen B! One old sow would not move so I hit her with the Hotshot. She fell over dead! I killed a 700lb pig with a Hotshot! Later I was told by one of the "paid" ranch hands that Hotshots have a warning on them not to use with swine!

Anyway, it goes to show you that it does not take much to shock the hell out of ya!

So how many times has that old sow been back to haunt you? Wait a sec, your in-laws ranch, better not respond to that question. [:)]

One thing I know is that a 1/10th of an amp across the heart can indeed kill a person.

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So how many times has that old sow been back to haunt you? Wait a sec, your in-laws ranch, better not respond to that question. [:)]

One thing I know is that a 1/10th of an amp across the heart can indeed kill a person.

I thought it was more like 1/100th. 10 milliamps.

Marc

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I was told that you will get a shock but it "should" not be lethal!

I just can't help to recall my days working on my in-laws ranch. We had a little device that was called a "Hotshot" imagine an electric fence on a 4' stick! They raised mostly cattle, but also had a few hogs that they kept for the grandkids, and eventually for the Easter dinner! One day I had the job of moving the hogs from pen A to pen B! On old sow would not move so I hit her with the Hotshot. She fell over dead! I killed a 700lb pig with a Hotshot! Later I was told by one of the "paid" ranch hands that Hotshots have a warning on them not to use with swine!

Anyway, it goes to show you that it does not take much to shock the hell out of ya!

I don't like those things. In addition to the danger that you discovered, they can really frighten the animals, and a frightened animal is a dangerous animal -- especially the ones that weigh more than you do.

I've found that rattling some feed in a coffee can will induce most farm animals to follow you wherever you go.

- Jim Katen, Oregon

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Quote: Originally posted by Scottpat

I was told that you will get a shock but it "should" not be lethal!

I just can't help to recall my days working on my in-laws ranch. We had a little device that was called a "Hotshot" imagine an electric fence on a 4' stick! They raised mostly cattle, but also had a few hogs that they kept for the grandkids, and eventually for the Easter dinner! One day I had the job of moving the hogs from pen A to pen B! On old sow would not move so I hit her with the Hotshot. She fell over dead! I killed a 700lb pig with a Hotshot! Later I was told by one of the "paid" ranch hands that Hotshots have a warning on them not to use with swine!

Anyway, it goes to show you that it does not take much to shock the hell out of ya!


I don't like those things. In addition to the danger that you discovered, they can really frighten the animals, and a frightened animal is a dangerous animal -- especially the ones that weigh more than you do.

I've found that rattling some feed in a coffee can will induce most farm animals to follow you wherever you go.



True story......

My buddy shocked himself for fun with one of those things while on a guy trip to the cabin last year. He won't be doing it again.
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So how many times has that old sow been back to haunt you? Wait a sec, your in-laws ranch, better not respond to that question. [:)]

One thing I know is that a 1/10th of an amp across the heart can indeed kill a person.

I thought it was more like 1/100th. 10 milliamps.

Marc

That is correct, Marc. A 1/10th amp can kill you 10 times better. The point is you can shock yourself silly as long as your heart does not come between the two points of contact.
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Quote: Originally posted by Scottpat

I was told that you will get a shock but it "should" not be lethal!

I just can't help to recall my days working on my in-laws ranch. We had a little device that was called a "Hotshot" imagine an electric fence on a 4' stick! They raised mostly cattle, but also had a few hogs that they kept for the grandkids, and eventually for the Easter dinner! One day I had the job of moving the hogs from pen A to pen B! On old sow would not move so I hit her with the Hotshot. She fell over dead! I killed a 700lb pig with a Hotshot! Later I was told by one of the "paid" ranch hands that Hotshots have a warning on them not to use with swine!

Anyway, it goes to show you that it does not take much to shock the hell out of ya!

I don't like those things. In addition to the danger that you discovered, they can really frighten the animals, and a frightened animal is a dangerous animal -- especially the ones that weigh more than you do.

I've found that rattling some feed in a coffee can will induce most farm animals to follow you wherever you go.

True story......

My buddy shocked himself for fun with one of those things while on a guy trip to the cabin last year. He won't be doing it again.

Ya, I did it to my foot one time just resting the dang thing and I hit the button. Most everyone I know that has messed with a Hotshot has hit themselves with it, either by accident or just to see what it was like!

The feed in a can works with a couple of critters, but when you are dealing with a few hundred it is a different story! Most of the time we used them to move the cows through the squeeze pen or to load them into trailers and trucks.

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Originally posted by Brandon Whitmore

Quote: Originally posted by Scottpat

I was told that you will get a shock but it "should" not be lethal!

The feed in a can works with a couple of critters, but when you are dealing with a few hundred it is a different story! Most of the time we used them to move the cows through the squeeze pen or to load them into trailers and trucks.

Yes, try to get a steer into the back of a truck for his first and last road trip to the butcher's place. A bit of grain in a can won't cut it.
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Yes, try to get a steer into the back of a truck for his first and last road trip to the butcher's place. A bit of grain in a can won't cut it.

Depends on how hungry he is and how he's been treated in the past.

My wife's family are farmers in southern Illinois. Their neighbor, who raises cattle, was trying to load trailer full of Black Angus. Their other neighbor, Lyle, came by to "help." Normally, Black Angus are pretty well behaved animals. But after most of the cattle were in the trailer, there were still two who proved recalcitrant and refused to get in. That's when Lyle had the bright idea to let out a war whoop, while waving his hat in his hand and jumping up & down. The whole truck full of cattle spooked and came roaring out of the truck, completely destroying the gate, and running straight over Lyle.

Through some amazing act of grace Lyle was unharmed. Several cattle, however, were bruised and got to live longer than planned.

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Here's OSHA's word from 1998. I don't think it has been superceded since then...

Current level

(Milliamperes) Probable Effect on Human Body

1 mA Perception level. Slight tingling sensation. Still dangerous under certain conditions.

5mA Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary reactions to shocks in this range may lead to injuries.

6mA - 16mA Painful shock, begin to lose muscular control. Commonly referred to as the freezing current or "let-go" range.

17mA - 99mA Extreme pain, respiratory arrest, severe muscular contractions. Individual cannot let go. Death is possible.

100mA - 2000mA Ventricular fibrillation (uneven, uncoordinated pumping of the heart.) Muscular contraction and nerve damage begins to occur. Death is likely.

> 2,000mA Cardiac arrest, internal organ damage, and severe burns. Death is probable.

References

NIOSH [1998]. Worker Deaths by Electrocution; A Summary of NIOSH Surveillance and Investigative Findings. Ohio: US Heath and Human Services.

Greenwald EK [1991]. Electrical Hazards and Accidents - Their Cause and Prevention. New York: Van Nostrand Reinhold.

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