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Made by Monkeys

The Range Had a Shocking Design Flaw

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jlawton
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Gold
Re: Circuit breaker?
jlawton   6/13/2013 10:11:43 AM
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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
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@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
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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.

GTOlover
User Rank
Platinum
Re: Shocking indeed
GTOlover   6/13/2013 8:51:04 AM
I would also point out Rob that , in general, the many commenters here tend to be a DIY type. Or at least they pay attention if the repair guy is called in. So the Made by Monkeys reading is informative to our engineering sense of reliability. In other words, we like to kill the issue and know we improved our stuff!

However, I think the general public does not pay close attention. If it is cheap, they can purchase optional extended warranty, and the appliance looks good, they contiue to buy and any issues with the previous appliance is forgotten by weeks end. How many times have you heard someone say, "Well it was old anyway and I really wanted a (pick your color) one!"

The extended warranty type programs from both the appliance makers or the big box stores extracts additional money from the consumer. The economics is such that they can afford to cut costs on the appliances. They have a business model that brings additional money in the form of an extended warranty. If this was not profitable, they would not offer it (or increase the price for it)!

I will say in this particular case, I think the potential for lawsuit is high and Jenn-Air should think about the costs!

Battar
User Rank
Platinum
Re: Shocking indeed
Battar   6/13/2013 8:48:09 AM
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Ann, the point is not how this got past QA, the question is how did this get past UL, or CE, or TUV, or GS, or ETL, or whichever regulatory standard the product was supposed to live up to. Did it have a regulatory lab approval? How many of us look for one when choosing an appliance?.

OLD_CURMUDGEON
User Rank
Platinum
Shocking INDEED & DANGEROUS!!!
OLD_CURMUDGEON   6/13/2013 8:40:13 AM
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Good detective engineering work on the homeowner's part, HOWEVER, if this happened to me, the FIRST phone call (or letter) that I'd forward would have been to the CONSUMER PRODUCTS SAFETY COMMISSION.  It is agencies of the gov't such as this one which DO serve a useful purpose, much unlike so many others!  It is unconscionable that a major appliance manufacturer, AND a top-tier one, to boot!, should market such an obviously defective appliance.

WAIT!..... I can hear the ambulance sirens with the ambulance-chasing lawyers in pursuit now......

Elizabeth M
User Rank
Blogger
Re: Shocking indeed
Elizabeth M   6/13/2013 5:04:39 AM
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I know, Ann! It really makes you wonder what's going on. It's a shame if people have to start worrying about the safety of their appliances from top brands, especially if historically everything was OK.

Charles Murray
User Rank
Blogger
Re: Shocking indeed
Charles Murray   6/12/2013 7:44:19 PM
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 Yes, Rob, as we've seen in Made by Monkeys, readers are also citing Maytag appliances, which were once the gold standard of appliance reliability. It looks like these quality problems are appearing in more and more brand names.

naperlou
User Rank
Blogger
Re: Shocking indeed
naperlou   6/12/2013 1:01:47 PM
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Rob, I think you are correct.  There seems to be a problem with testing and engineering.

Bernard, did you contact the manufacturer?  Perhaps their Big Data efforts will pick this article up.

Ann R. Thryft
User Rank
Blogger
Re: Shocking indeed
Ann R. Thryft   6/12/2013 1:01:19 PM
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Wow, yet another failure, and potentially dangerous one, by a major white goods manufacturer. Like others, my only question is--how the heck did this get past QA?

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