Gfci Alci Not Working

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nakulak

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I would really like to see some testing done on this stuff. These demonstrations are nice, but it would be nicer to see some controlled experiments, tests with grounded water, explanation of the inner wiring of the devices (or a simpler alternative device).
 
iwire

iwire

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joe tedesco said:
This one tripped the GFCI immediately.
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Same sink? Or a different sink with a grounding path?

It seems that ii this test there was another current path other then the circuit conductors which is suppose to trip the GFCI.
 
charlie

charlie

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76nemo said:
That one also had constant water pressure feeding the sink, "grounding" it.
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Not necessarily. Pure water by itself is a reasonable insulator and plastic water lines are fairly common. Without a path to ground, the GFCI will not work but Joe could have provided that path if he had just put his hand in the water and contacted a grounded surface. The problem with doing that is the current will flow through Joe until the GFCI reacted. The reaction time will depend on how many ma are flowing to ground. ;)
 
76nemo

76nemo

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Location
Ogdensburg, NY
charlie said:
Not necessarily. Pure water by itself is a reasonable insulator and plastic water lines are fairly common. Without a path to ground, the GFCI will not work but Joe could have provided that path if he had just put his hand in the water and contacted a grounded surface. The problem with doing that is the current will flow through Joe until the GFCI reacted. The reaction time will depend on how many ma are flowing to ground. ;)
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Point taken;)
 
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nakulak

Senior Member
maybe if joe were to coat his skin with a conductive ointment prior to doing the experiment it would not be too harmful (skin effect hehe)
 
LJSMITH1

LJSMITH1

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Location
Stratford, CT
What about the conductive path of the H2O inside the hairdryer motor and switch? Surely the motor and/or switch is connected tothe neutral and ground, right?. Well if there is water inside the motor, the GFCI *should* trip - with or without a grounded sink or water basin.

The GFCI operates by sensing the difference between the currents in the Hot and Neutral conductors. Under normal conditions, these should be equal. However, if someone touches the Hot and a Ground such as a plumbing fixture or they are standing in water, these currents will not be equal as the path is to Ground - a ground fault - and not to the Neutral. This might also occur if a short circuit developed inside an ungrounded appliance (i.e. water bridging hot and neutral surfaces) or if someone was working on a live circuit and accidentally touched a live wire.

A GFCI tests for a Grounded Neutral Fault and a Hot to Ground Fault. Both of these should occur when an appliance is dropped into water - thus tripping the GFCI circuit. The video appears to show a defective GFCI plug unit. As to why the GFCI receptacle did not trip, I think it has something to do with the defective GFCI plug. I wonder if the GFCI receptacle would properly trip if you cut that GFCI plug off and installed a standard NEMA plug?

One other check would be to see if the GFCI receptacle was correctly wired. I have seen retrofit installations where the installer 'tricked' the GFCI by jumping the neutral and ground on the GFCI.

Just my $.02...
 
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