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Thread: Leviton GFCI nuisance tripping and circuit analysis

  1. #51
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    Quote Originally Posted by ptonsparky View Post
    We could put the heaters on a GFCI. We can put a GFCI on anything we choose. We don’t have to. The trick is we generally have a functional Equipment grounding conductor along with a neutral at each building. A properly installed EG reduces the shock hazard considerably. Protection by a GFCI does not eliminate the possibility of shock from an improperly grounded piece of equipment.
    In the Philippines. All of our appliances (Refrigerators, Washing Machines, Heaters), etc. have no grounding or EGC. All the plugs are two prong. For example. This is the heater we commonly used in our bathroom.




    The plug is 2 prong made in Malaysia. Available at https://wschoo.en.ecplaza.net/produc...-series_646890 It's multi-point heater 27Ampere.

    What do you mean "Protection by a GFCI does not eliminate the possibility of shock from an improperly grounded piece of equipment". Can you give example? Since the Multipoint heater doesn't have EGC. I guess putting it to the Siemens GFCI breaker would be great idea (rather than nothing). The Meji FM2141 (used by Leviton) based GFCI is only up to 20A. The heater is 27A. Millions of homes installed it that way without any EGC or GFCI. 99.99% of filipinos don't know the meaning of GFCI.

  2. #52
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    I don't know whom you're quoting, but a GFCI can't protect against a line-to-neutral shock.

    A shock is required for a GFCI device to function; it's designed to prevent electrocution.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  3. #53
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    Quote Originally Posted by LarryFine View Post
    I don't know whom you're quoting, but a GFCI can't protect against a line-to-neutral shock.

    A shock is required for a GFCI device to function; it's designed to prevent electrocution.
    Neither can an EGC protect against a line-to-neutral shock which is equivalent to putting your fingers at the two holes of outlets. Of course this is extreme that happens rarely. Your EGC only protects any hot touching the metal chassis which trips the breakers. It doesn't protect against line-to-neutral shock.

    In our country. Since we don't use 120v neutral as I detailed before, and we used your USA equivalent of red and black line to line of 240v. Then I know a GFCI doesn't protect against a line-to-line shock. Neither does any EGC.

    But with GFCI guaranteed to trip at 5mA. It can protect even against shock and electrocution (provided only one line touched against any ground (natural concrete or EG or GEC), isn't it. Shock is when the current is above 10mA. I was able to verify that the Meiji outlets trip at 5mA by using this equipment at their head office (it's the technican fingers holding the GFCI).


  4. #54
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    Quote Originally Posted by ptonsparky View Post
    I used a ‘snubber’ on the bath fan that was giving me grief about 9 years ago. Not a problem since.

    IIRC, it didn’t matter whose GFCI device I used. Different circuits. No interconnection until the neutral bar.
    When the following is put between the shaded pole motor and the GFCI outlet (with FM2141 chip used also by Leviton). There are no more trips after repeated switchings (whereas with it removed, it trips 4 out of 5 times).



    The red stuff is capacitor with rating of 0.0042 uF.
    The coils are wound on a ferrite (semi-metallic) core.
    It seems to be LC filter type, designed to mainly filter out electrical interference.

    But something confuses me.



    The cover said "Voltage Surge Protector". There is no MOV (metal oxide varistors). Do you considered LC filter as surge protector too? It's made locally in the Philippines and I can't find it anymore. Here we don't have any UL, CE or don't consider them before accepting it. Is it a fake surge protector when it's just an LC filter?

    What kinds of surges can LC filter remove versus that of MOV? Sorry I forgot my lessons 25 years ago. We were not taught about MOV. So I'm quite confused especially with the paradoxical labelling above.. Thank you.

  5. #55
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    Quote Originally Posted by tersh View Post
    Do you considered LC filter as surge protector too?
    No, unless the surge is only of frequencies above the filter's cutoff.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  6. #56
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    An equipment ground during a fault may only carry millamps. It may carry hundreds of amps and it may carry that current forever, dependent on the size of the overcurrent protection ahead of it. A 16 amp fault to the tank of the water heater and Equipment Ground will not trip a 20 amp breaker. As far as the breaker is concerned that is just part of the load. A properly installed EG reduces the shock hazard should some one touch the water heater. You may not even feel one. The potential is reduced. Remove the EG and you have full potential. Add a GFCI to an EG and the current flow is reduced to the 5ma on the EG. Remove the EG and the potential rises. You know this.

    Your definition of shock appears to be what we call electrocution, ie death.
    Tom
    TBLO

  7. #57
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    Quote Originally Posted by LarryFine View Post
    No, unless the surge is only of frequencies above the filter's cutoff.
    What components of inductive kick can be filtered by LC filter? Does inductive kick produce any RF components that can be filtered by LC filter? I'm wondering this because since the LC filter eliminate the trips of the shaped pole motor, then is it really inductive kick causing the GFCI trips or RF?

    Do you know of a web site that summarizes the waveforms of inductive kick, RF interference filtered by LC filter, Surges, RC snubber, (what else) and how they differ between one another?

  8. #58
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    Quote Originally Posted by ptonsparky View Post
    An equipment ground during a fault may only carry millamps. It may carry hundreds of amps and it may carry that current forever, dependent on the size of the overcurrent protection ahead of it. A 16 amp fault to the tank of the water heater and Equipment Ground will not trip a 20 amp breaker. As far as the breaker is concerned that is just part of the load. A properly installed EG reduces the shock hazard should some one touch the water heater. You may not even feel one. The potential is reduced. Remove the EG and you have full potential. Add a GFCI to an EG and the current flow is reduced to the 5ma on the EG. Remove the EG and the potential rises. You know this.

    Your definition of shock appears to be what we call electrocution, ie death.
    I was just saying the discoverer of GFCI tested different mA on people. At 5mA, one would get tinging. At 10mA (?), one would begin to get shocked.

    Btw. If you don't have EG (Equipment Ground). Remember all our appliances in the country don't have Equipment Ground or EGC. I'd like to know how fast is the response time of a 5mA GFCI? If a person got accidentally exposed to one of the live wire with feet on the concrete floor. And there is potentially a 10A exposure, how fast can the 5mA GFCI relay opens and how much current would still pass through him? If the relay open longer than the current moving through it, then can you still get electrocuted? If so, then what is the use of GFCI?

  9. #59
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    190111-0830 EST

    tersh:

    You continue to have false impressions because you do not go back to basics.

    Look at the GFCI datasheet for the trip time characteristic. There is an inverse time relationship, electronic in this case, relative to current. The 5 mA is after a moderately long time relative to how little time it takes for you to detect a shock. Further you can detect a shock at a much lower level than 5 mA.

    See https://pdfs.semanticscholar.org/368...68f166bb3d.pdf
    1 mA looks to be a better level for detectability for ordinary people. An interesting side note is that John Swets is referenced in this discussion. I first met him in 1953 when I was in a psychology class taught by Wilson (Spike) P. Tanner. Tanner and Swets were both PhD students at the time working on signal detectability, and running vision experiments. I became a subject, about $1 per hour. That summer I started building test equipment for Tanner's experiments.

    Note that a 1 mA shock could kill you indirectly. You stand on a ladder, get shocked, fall off, crack your head on the floor, and die.

    At 5 mA you will feel a substantial shock.

    What is a surge, transient, impulse, RF, etc. Their meanings are all dependent upon context.

    More later possibly.

    .

  10. #60
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    Quote Originally Posted by tersh View Post
    I was just saying the discoverer of GFCI tested different mA on people. At 5mA, one would get tinging. At 10mA (?), one would begin to get shocked.I have talked to people that have tripped a GFCI through their body. It was not a tingle. Try it yourself if you like but remember GFCIs have a lot of footnotes about the general health, age, and conditions of the recipient surviving said 5ma tingle.

    Btw. If you don't have EG (Equipment Ground). Remember all our appliances in the country don't have Equipment Ground or EGC. I'd like to know how fast is the response time of a 5mA GFCI? If a person got accidentally exposed to one of the live wire with feet on the concrete floor. And there is potentially a 10A exposure, how fast can the 5mA GFCI relay opens and how much current would still pass through him? If the relay open longer than the current moving through it, then can you still get electrocuted? If so, then what is the use of GFCI?
    The GFCI is used to limit your exposure to potentially harmful or lethal currents. It does not prevent a shock especially when no EG is used. It may prevent electrocution. Change your terms.
    Tom
    TBLO

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