Hello Bernard. I retired from an appliance manufacturer--not Jenn Air and I can tell you I am not really that surprised. For radiant elements under glass, the technology is basically the very same. A spring loaded "can" is held against the glass surface to provide necessary conduction to the utensil above. Manufacturers use the very thinnest of materials to accomplish this and a "vigorous" transit experience can cause the entire assembly to dislocate. Vibration analysis would solve this problem or allow engineers to strengthen the components but sometimes the "need for speed" to market does not allow. (I only hope medical equipment is not made with the same quality criteria.)
kenish, it probably was an error on my part after a quite hard working day. Sorry if I jumped on you hard about it. But I still find the concept of electrically hot garage doors very unlikely, but it is true that one would get quite a shock, since at least on my garage door it takes a good grip on the handle to get it moving. A deffective opener on a two-wire extension cord could be a good security system as it would certainly make it a lot riskier for the bad guys to open the door.
And as I think about the stove with the open neutral conductor, I think about the way my dad wired up an electric stove at his cottage. He accidentally exchanged one side of the 240 volt line with the neutral connection. If he had checked the voltage on the outlet with a meter the problem would have been obvious, but he didn't, and so for about five years people occasionally got shocks off of the stove. He used three black wires and didn't mark them adequately. And if he had only metered from each side to neutral it would have tested OK.
I generally agree with your comments. But had you read my post, I commented it was an open neutral, not an open ground. Also, nowhere did I say it's a huge, rampant problem. That said, the handful of people electocuted by "hot" garage doors is apparently enough that it's part of the 2008 NEC for new construction and retrofits. So neither "spewing", nor "misinformation"....you can take up the debate with your building inspector or real estate appraiser if you don't agree with the NEC requirement.
Why in the world would a garage door beome electrified just because the grounding circuit on the opener failed??? Only if there was an unintended short circuit in the opener would that happen. Failure of a safety system does not intrinsicly cause a dangerous situation, it only allows it to potentially happen. Most of the time the failure of the intentional (frame) ground does not lead to any problems at all, since most equipment and appliances seldom develop short circuits to the frame. On rare occasions such faults do happen, and in those instances a properly functioning frame ground will prevent a shock hazard from developing. So it would be a public service to avoid spewing misinformation about the degree of hazard arising from the failure of a safety system. While the failure of the frame ground could allow an unsafe condition to develop, it does not automatically create a dangerous situation with an actual danger present.
There are a few plastics that would serve quite well as a front-mounted control panel on an electric cook-top. They are some of the more expensive thermoset plastics, not the cheap thermoplastcs preferred by so many maufacturers. Thermosets are at a disadvantage in that unusable parts can't be simply reground and re-melted. But they can have much higher heat-deformation temperatures and they can be stronger, with better electrical properties and reduced moisture absorbtion. But those benefits are ignored by those companies that choose to provide much less quality along with many more features.
I was shopping for a new, higher-end range and the saleswoman in a big box store was surprisingly savvy and helpful. She steered me away from Jenn-Air, and showed me why (they carried the brand). The front-mounted control panel was semi-rigid plastic. The first time boiling water or hot grease spills on the panel, guess what happens? I purchased a similar range from GE with a glass touch panel. Hopefully Jenn-Air has corrected this. The engineer or accountant who chose plastic must never have used a cooktop!
Not only the 110VAC fan, but also any 110VAC light bulbs in the range! Adding to your comment, there is some confusion in several other posts between a circuit breaker and a GFCI. A CB protects against overcurrent but not ground faults while a GFCI is exactly the opposite. A line protected only by a CB will still do a great job electrocuting someone unless there is a GFCI as well.
Total tangent...a new part of the Electrical Code requires garage door opener outlets to be GFCI protected. If the neutral goes open, the garage door opener, rail, and the entire door (if it's metal) will be energized. There's been a handful of electocutions when people touched a "hot" door.
I think in the discussion above there is one point that is being misinterpreted. I'm almost sure that the author's reference to the circuit breaker was the 2-pole breaker in his main distribution panel.
Furthermore, historically for electric ranges w/ knob-control, when the burners are on low heat settings they are powered at the 120v level.
Also, please be aware that up until a recent NEC (NATIONAL ELECTRIC CODE) code change, it was permissible in standard one & two family dwellings to use the either #8 or #6 2-wire /w GND for connection of the range. The exact wire size was determined by the total ampacity of the range. The code discusses this as 10KW above & below. This allowable connection also existed for electric clothes dryers. They were typically fed from a #10 2-wire w/GND cable (ROMEX, BX, etc.) The one exception to this code rule was for mobil homes. For both the cook range AND the clothes dryer, they required a different connection. In both cases, the cables had to be a "3-wire w/GND" cable. When the connections to the supplies were made with attachment cordsets & receptacles, there are NEMA designations for each configuration. The latest NEC rules however dictate that electric ranges AND clothes dryers be connected with the appropriate "4-prong" cordsets, IF NOT directly wired to the feed cable, since both appliances are considered to be permanently placed. The point is that the previous code revisions allowed the NEUTRAL AND the (green or YELLOW/GREEN) conductor to be the SAME physical piece of wire. Now, however, with the recent change, the circuiting must be done so that the NEUTRAL conductor and the GROUNDING counductor ARE two separate physical pieces of wire. One final note regarding conductors..... the NEC provides definitions for these conductors. The NEUTRAL conductor is the "IDENTIFIED" conductor in cordage, and it is the GROUNDED conductor in such electrical distribution systems. The GREEN, YELLOW/GREEN or BARE conductor is the GROUNDING conductor, normally carrying NO current, in position simply as a "safety" conductor.
Linear guides are one of the most important components required for the design of automated or computer-controlled equipment. Aluminum profile extrusions, used for these guides, can enable designed-in functional features.
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