Induction Cooktop Explosion
Hi, good folks,
I experienced what I can’t help but describe as a Hiroshima-like blast two mornings ago, and I am soliciting thoughts to discuss on the FHB podcast . . .
My two-burner plug-in induction stove top EXPLODED. I’m talking burning glass embedded in the walls and floor. It was horrifying. If I had been standing anywhere near it, I’d be in the hospital right now, likely blind for life. My cat was in the room–it’s a miracle he didn’t get hurt.
I asked Mike Maines what might have caused it and he said it could be from impact, thermal expansion, or a nick in the safety glass. I didn’t mention to him that I had been using a kettle that was not rated for induction use. Could this be a factor? It took forever to heat up but it never occurred to me that it could be a safety issue. Has anyone else had this happen? Any related thoughts to share?
Still thanking my lucky stars,
Kiley
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Replies
This thread needs photos!!!
If you really feel someone could have been injured consider making a report to the government department “Consumer Product Safety Commission”
https://www.cpsc.gov/
Wild guess is there was enough steel around the rim of the kettle to convince the sensors a compatible pot was on the burner. The rim became very hot over heated a small spot on the glass making it fracture
Walta
+1 on this is a CSPC worthy event. Take as many pictures as possible -- retain the old stove carcas. https://www.cpsc.gov/
Dang,
Glad you're OK! What an experience!
Kiley, you had said "explosion" but I thought you were being figurative, not that you had glass embedded in the walls and ceiling! I've broken safety glass on several occasions and it hasn't been very dramatic. I think Walta is probably right. Induction cooktops work by creating an electromagnetic charge within the cookware, so if there was some conductive metal in the kettle, it probably got very hot. Did the kettle survive? I'm guessing that it might have exploded first, shattering the cooktop in the process.
The kettle was intact, Mike. (Yeah, it was seriously scary. It's not out of the realm of possibilities that, had I been standing over it, I could have died.)
I do wish I took photos, Walta, but I was so shaken and not thinking along those lines. What a MESS!!!
Kiley,
Scary stuff. No insight into its case, just relieved you are alright. Stay well!
I was able to obtain a photo of Kiley's kitchen, attached. But seriously, I'd be curious to hear more forensic details. Was the kettle thrown quite a ways? (BTW, did it only contain water?) What was the splatter pattern of wall-embedded glass? It could have been a multiple-stage breakdown; perhaps the kettle failed first--in an explosion or in a gentler fashion--spilling cold liquid on the glass which then fractured. There's also the phenomenon of exploding water, and maybe the glass shattered only due to the kettle jumping around: https://indianapublicmedia.org/amomentofscience/exploding-water.php
This is a CSPC worthy event, and should be reported. Take as many pictures as possible. https://www.cpsc.gov/
Whatever the cause: be it a manufacturing defect or a user issue, it should be investigated.
It could be a glass issue more than an induction issue.
Let's say some induction component did blow (maybe a capacitor); shouldn't the glass still not break in as dramatic a manner?
Then again, you say the glass was especially hot? Like hotter than it would get during a heavy sear, etc.?
https://youtu.be/M4PWihN_0_8
^ stories of glass tops exploding in Australia
I've personally experienced a similar explosion, using a PYREX casserole dish with pancakes, on 2 burner counter-top electric element burner (old school) to keep them warm. It was during a staff breakfast. The Pyrex literally exploded, with glass fragments burning the Arborite table laminate and glass everywhere. I think the pancakes in the dish prevented serious injury to my staff in the room at the time. The two burner electric hot plate was set to "warm" only, but there was either an issue with it, or poor temperature management on the device. Evidently thermal shock cause the issue to the Pyrex dish in that case, and was quite dramatic. Lesson learned.
My guess is that the kettle overheated the glass surface, perhaps due to the composition of its base. You want to use only pots that are strongly magnetic at the base. There is a very noticeable difference even in "induction" rated cookware with respect to heat transfer/performance. In our induction cooktop "collection" the cast iron pans work the best.
If you think about it, a pot with water in it should not exceed be able to exceed much beyond 100C, unless it is empty. That said, a base that is has a very thin ferrous metal layer facing the induction surface may get quite hot, while not adequately transferring that heat via a non-ferrous layer above it to the water. Think thick copper core sandwich. That two burner induction unit may not have overheat protection to prevent this type of issue...
Kiley Have you ever been around tempered glass when it breaks?
It is always a dramatic event because of the nature of the material.
When they make tempered glass, the idea is to store a large amount of potential energy in the glass. The idea is when the glass gets broken the energy is released fracturing the glass into pieces so small, they are unlikely injure anyone. It would not be uncommon to find glass 10 or more feet away.
Embedded glass in the walls does not sound normal and I would like to see photos of the damage.
I think of tempered glass a like a compressed spring I have seen it explode for no apparent reason when no one was near. I have had it explode in my hands when I looked at it wrong.
Walta
Thank you for the information, Walta (and everyone who contributed to this thread). I do plan to talk about it on the FHB podcast we are recording this morning and will share your thoughts; and I look forward to hearing more on the matter from listeners. (Science is FASCINATING!) Although I didn’t take photos at the time, and the aftermath is not visible ("embedded" is not the right word; "temporarily stuck to" is more apt), here is a photo of the stove itself after the fact; it indicates the size of the shards that blew…
Maybe I'm missing something, but neither burner looks busted. An iduction unit has a large wound copper coil with ferrite cores in it which are very visible with the glass removed.
That looks more like a standard ceramic cooktop.
In either case it should not have exploded. The material used for these should be a ceramic, not glass, which has near zero coefficient of thermal expansion. This means you can heat it up to very high temperature and shock it with cold water and it won't crack.
Yeah that looks like one of these: https://www.cusimax.com/products/cusimax-1800w-stainless-steel-silver-double-hot-plate or these: https://www.cusimax.com/products/cusimax-1800w-silver-ceramic-cooktop-dual-infrared-burner, not induction. Cusimax has induction hotplates but they look like this: https://www.cusimax.com/products/cusimax-1800w-induction-cooktop-with-smart-sensor-touch-kids-safety-lock.
That's definitely not an induction cooker.
Tempered glass, when it breaks, makes lots of little pieces that don't have sharp shard-lide edges and points for the most part. This is what makes it "safety" glass -- it doesn't break into knife-like shards the way regular plate glass does. I have seen it break in my presence before, and usually it just shatters nearly instantly into a zillion small pieces that drop to the floor -- it's not really an "explosion".
I'm not so sure those cooktop surfaces are just tempered glass though, I think they are something more interesting that can handle impact and heat better. regular tempered glass is actually not all that hard to break if you scratch it, which is why I think it might not be the issue here.
Regarding the "induction rated" cookware -- that rating means there is some ferromagnetic material in the bottom of the pot/pan that the inductive cooktop can heat up. Induction cooking doesn't heat the way a usual burner does, it uses high(ish) frequency magnetic fields to cause ferrous materials to heat up due to eddy currents. The actual heat is generated WITHIN the ferrous material of the pot. If that material isn't present, the pot generally won't heat up. If there is a too-small amount of the material present, you might get localized heating, but I don't think you'd get an explosion BUT I haven't ever tried that.
I wouldn't be surprised if some component inside the cooktop exploded. I would suspect a capacitor, but probably it wasn't a single failure, which would typically just shut the thing down. You may have had multiple, simultaneous failures that caused the "big bang" you experienced. If you have some detailed pics of the interior of the induction cooktop I might be able to get a better idea.
Glad you're OK though!
BTW, "Pyrex" hasn't been the "pyrex" it used to be for some time now. Pyrex used to be made from borosilicate glass, which is the same stuff used to make laboratory glassware. Pyrex now is just a brand, and it's made with regular soda lime glass now. You CAN still get pyrex the way it used to be, but you have to order it from Arc Cuisine in France, which apparently licensed the design decades ago and still makes the old-style pyrex cookware using borosilicate glass.
Bill
Kiley, one thing's for sure, my staff and I will remember that morning very well as it was very dramatic, and scared the crap out of all us with regard to the violence of the event.
Bill, I have not come across a good test of comparative induction performance, but I've personally measured it on a few pans we've purchased for use on our induction cooktop. Given that induction does work by heating up the pan base, it follows that varying material, thickness and thermal conductivity in the base will have an effect. In our case, I noticed one smaller non-stick (new) pan heated water in the area of 50% slower than other similar sized pans in the collection.
My concern with an event like Kiley's is that a thin layer of ferrous metal directly adjacent to the glass followed by a thicker layer of non-ferrous metal might actually elevate the glass temps vs a thicker layer (like cast iron) where heating would be better distributed. You can predict induction performance by testing pan bases with a rare earth magnet. Strong attraction vs weak gives you an idea of the base alloy, which in turn will predict how well it heats up.
Another issue might be related to running the induction unit at full power for an extended period (due to a poorly performing induction surface) as normally you might run full power for just a minute or two to get to a boil, then back the controls off. The whirlpool counter top unit we have does have cooling fans that fire up after extended use.
My setup is a bit unique in that I'm using automation on the cooktop's 240V power supply (to control the exhaust fan system) which also monitors power use of the unit. It does vary power use at higher induction settings as you'd expect, but it also cycles power to the induction coils (as in on/off) at lower settings.
If this is typical, (https://www.allaboutcircuits.com/news/teardown-tuesday-induction-cooktop/) then there should be a temp sensor under the glass to cut power at a given temp, in this case, 363 F. If the kettle Kiley used has a raised area in the center (as some older pots/pans do) then then I could see a situation where the centre of the glass might be not only cooler than the outside diameter, but also cool in a spot where the temp cutoff sensor is located. You can guess what might happen then...
This is where the CSPC comes in. An example of a range explosion that resulted in regulatory change took place in Truckee, CA where a antifreeze sprinkler let loose due to a cooking fire. The resulting explosion opened regulatory eyes to several previously unknown dangers.