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jlawton
User Rank
Gold
Re: Circuit breaker?
jlawton   6/13/2013 1:07:50 PM
NO RATINGS
That may be how it connects, that may be what it's sold for, that may be a useful circuit that protects reasonably well for a lot of purposes, but you just can't "prove" that the current that the circuit detects ACTUALLY flowed into a node (ground) the load isn't even connected to. Certainly it's a FAULT current detector, but I defy you to prove it's a GROUND fault current detector. Semantics maybe, but nonetheless the premise isn't really valid, I don't care how many connection schematics or usage manuals or any other diagrams or material you try to use to "prove" your assertion, sorry!

Rob Spiegel
User Rank
Blogger
Re: JennAir on the line
Rob Spiegel   6/13/2013 1:01:26 PM
NO RATINGS
Hi Jordan, Nice to see you weigh in. I'll make sure Bernard gets your message.

JennAirUSA
User Rank
Iron

JennAirUSA   6/13/2013 12:55:35 PM
NO RATINGS
Hi Bernard, my name is Jordan and I am a representative of JennAir. I am terribly sorry to learn of the experience you have had with your range and sincerely hope no one was hurt.  So we can look into this further review, please reach out to me via e-mail at JennAir.Digital@JennAir.com with ticket number 48193. Also, please include your name, your complete contact information with the model and serial number of your range. 

Ann R. Thryft
User Rank
Blogger
Re: Shocking indeed
Ann R. Thryft   6/13/2013 12:49:59 PM
NO RATINGS
Battar, it's both. Before receiving UL or other such approval, usually there's an internal QA cycle so the product doesn't fail those external tests.

RPLaJeunesse
User Rank
Iron
Re: Circuit breaker?
RPLaJeunesse   6/13/2013 12:07:18 PM
NO RATINGS
My point is that GFCIs are not for use just on unbalanced lines like you seem to believe. That may be true for 115VAC GFCIs, but not all GFCIs. For a 2-pole GFCI to work properly the load neutral need not even be connected (although the GFCI must have its neutral line connected). Perhaps this will help, from http://w3.usa.siemens.com/powerdistribution/us/en/product-portfolio/circuit-breakers/residential-circuit-breakers/gfci/pages/gfci.aspx?tabcardname=Wiring%20Diagram 

GFCI Wiring

jlawton
User Rank
Gold
Re: Circuit breaker?
jlawton   6/13/2013 11:39:48 AM
NO RATINGS
I can't for the life of me understand what your problem is here. The "center tap" of the pole pig for the line phase serving this area is of course grounded. A "standard" GFCI uses a differential current transformer which typically services just one side of this transformer. The entire premise is to ensure that the exact amount of AC current that flows out of the "hot" leg is returned through the wiring provided for the return circuit, if instead it goes to ground through an alternate path that's a fault and upon detection the circuit would of course be opened. If you were to try to make this work on a circuit that's wired only across two hot legs, you only have the two legs to sense current on, NEITHER of them is "ground current" per se so there's no way to sense a fault to ground, all you could do is sense a "sneak path" to the opposite hot side of the transformer but what good is that? A GFCI doesn't have any "magical" abilities, it just senses current differences in order to detect problems that cause it to sense certain problems by working the way it's designed to work. I don't know how this got so far off topic anyway, from all we can tell there wasn't even a GFCI at the circuit level so in the case at hand there wasn't any protection at all, the worst possible case!

RPLaJeunesse
User Rank
Iron
Re: Circuit breaker?
RPLaJeunesse   6/13/2013 10:32:51 AM
NO RATINGS
I would consider "the same" leakage from a balanced (with respect to ground) pair (e.g. 230V home power) would imply either two identical leakage impedances occurring simultaneously (highly unlikely) or a line-to-line bridge which, by its nature, is not a ground fault. Admittedly, bridging the lines could be quite deadly nonetheless, but may constitute a double fault (i.e. product design dependent). For a single point of influence to affect both lines of a balanced pair equally it would have to be at the center point of balance, which by nature is 0V and hence not a point of danger for causinng electric shock. Similarly having "the same" leakage from an unbalanced pair (e.g. 115V) to be a double fault condition, as there would need to be two simultaneous leakage paths of wildly different impedances, occurring at exactly the same time. Again, highly unlikely. 

jlawton
User Rank
Gold
Re: Circuit breaker?
jlawton   6/13/2013 10:11:43 AM
NO RATINGS
Sorry, you're not thinking clearly here. If you have the SAME "leakage" between BOTH legs and ground then the leakage can cancel out in the difference sensing trabsformer and then you can't tell there's a fault to be sensed hence there's no protection. (It MIGHT not cancel equally but that hardly constitutes protection!) In order to guarantee that a fault would be detected under those circumstances it would have to be a sizable percentage of the load current, not the 15 mils or so that's guaranteed to cause a trip in a properly designed system. Anyway the author of the piece said it was a circuit breaker anyway not a GFI (or GFCI). An appliance for which design depends on external circuit protection to be operated safely is a disaster waiting to happen.

RPLaJeunesse
User Rank
Iron
Re: Circuit breaker?
RPLaJeunesse   6/13/2013 9:46:30 AM
NO RATINGS
@jlawton The operation of a GFCI does not depend on any inherent connection of the GFCI to neutral, or even to "ground". It simply looks at the current out one wire and back the other. If there is a difference the current must be going somewhere unintended, probably somewhere not good. If the difference is above threshold then both load wires are opened, preventing any further fault current. The GFCI neither knows nor cares where the fault current goes. In fact, leakage from a higher voltage would cause a fault current just as well as leakage to "ground".

jlawton
User Rank
Gold
Circuit breaker?
jlawton   6/13/2013 8:55:04 AM
NO RATINGS
I would hope that a design that's even at risk for a flaw like that would be designed with protection against it. Common sense suggests that if the design were capable of having an electrical shock hazard, as long as it was a 115 volt circuit it would have to be protected with a ground fault interrupter (GFI) rather than a circuit breaker. But when BOTH supply legs are "hot" (as in a 230 volt circuit, which is typical for a range) it's not inherently obvious that there IS a simple way to sense a low current fault! If the individual elements are wired between "hot" and ground then it should have been up to the range manufacturer to provide GFIs for each element because it isn't even possible to protect the device at the circuit level, otherwise it would seem this is WAY beyond a simple "flaw", it's a total design failure if the entire CONCEPT is unsafe.

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