Basic Electricity Video

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tallgirl said:
While on You Tube I found two interesting, non-humourous, videos from our own Joe Todesco --

http://www.youtube.com/watch?v=oFUgveAdB2k
http://www.youtube.com/watch?v=-M8fFzl365Q

Now we know what he does when he stays in hotels ...
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I would like to point out that, technically speaking, the GFCI's did not fail to operate (test button aside): nobody was receiving a shock. There was no pathway back to the neutral, and the power cords contain no EGC. All that was proven is that the drain system is not grounded and/or contains plastic.

Added: In other words, all of the current supplied by the hot was being returned by the neutral.
 
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stickboy1375 said:
... had someone put their hand in that sink (which I wish they had) the gfi would had tripped...
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...as long as the combined total impedance of the pathway through the body, floor, etc. was approx. (120/0.005) 24K or less.

But, yes, that is the intention. :D
 
stickboy1375 said:
I agree... had someone put their hand in that sink (which I wish they had) the gfi would had tripped...
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What, you don't like Joe?!?

That's one thing I don't understand about GFCIs and two wire devices. If you're in a tub with no connection back to ground -- like, if your plumbing is PVC from the drain on down -- what's the point? Or maybe that is the point -- the lowest resistance path is inside the blow dryer.

On a more interesting note, I was surprised that the blow dryers worked as well as they did in the water. I forget the density conversion between water and air, but water is a LOT denser than air.
 
tallgirl said:
What, you don't like Joe?!?

That's one thing I don't understand about GFCIs and two wire devices. If you're in a tub with no connection back to ground -- like, if your plumbing is PVC from the drain on down -- what's the point? Or maybe that is the point -- the lowest resistance path is inside the blow dryer.

On a more interesting note, I was surprised that the blow dryers worked as well as they did in the water. I forget the density conversion between water and air, but water is a LOT denser than air.
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You need to get caught on" Myth Busters" they did the hair dryer in the bath tub trick with a balistic dummy in the tub. Also the toaster in the tub. Note that the more "pure" the water the less conductive it is. No impuritys no cuntuctive.
 
acrwc10 said:
No impuritys no cuntuctive.
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I went down a set of basement stairs once for a service call. I already knew that the basement had water in it, so I had rubber boots on. To my surprise, I saw a power strip, plugged into a GFCI, on while it was underwater. The light on the switch was still glowing. Gulp...
 
tallgirl said:
What, you don't like Joe?!?

That's one thing I don't understand about GFCIs and two wire devices. If you're in a tub with no connection back to ground -- like, if your plumbing is PVC from the drain on down -- what's the point? Or maybe that is the point -- the lowest resistance path is inside the blow dryer.

On a more interesting note, I was surprised that the blow dryers worked as well as they did in the water. I forget the density conversion between water and air, but water is a LOT denser than air.
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GFI's measure current IN and current OUT, when that changes, the gfi trips, A good way to make it trip would to stick your hand in that sink with the hair dryer....:) The ground on a GFI is for OCP only...
 
I liked the explanation of how the power company charges you over and over for the same electricity without getting caught because no one really checks. That was funny.
 
stickboy1375 said:
The ground on a GFI is for OCP only...
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No, it's for equipment grounding/fault protection. The circuit breaker (or over-current portion of a GFCI breaker) is for OCP.
 
stickboy1375 said:
I should have reworded that...:) I meant to say, provides a low current path for the OCP to open...
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Well, yes in the sense that one device does both functions: ground fault and overload. The EGC has no funtion in over-current protection, only equipment ground faults.
 
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