Spectacular solid state relay failure

I wired up a solid state relay to only turn on the hot water tank when electricity is cheapest. Using a 25 amp relay to switch about 22 amperes. I guess that was too close to it's rating. No issue for 4 months, then failed spectacularly.
My previous video of this set-up:
• Hot water heater time ...
"bigclivedotcom" has done a teardown and analysis of one of these:
• Teardown of an eBay 25...

[@jeremyturner2873]

It decided to become a plasma state relay.

[@AbdulKarim-fs5iw]

That cracked me up...

[@Petertronic]

A comment from the original video said: "The fakes do have a bad habit of catching fire."

[@First2ner]

at least you had a house to sell after this

[@davidchuang4927]

This is an application where a standard mechanical relay would be better. A SSW is more suited to situations where the load needs to be switched on/off rapidly or in short intervals, such as in the case of a PID controlled heater application. If the point was to maintain the tank temperature within a very narrow range at all times, then an SSR with a PID controller would be ideal. However, in this example, since the system is either on or off for long periods of time, a stout mechanical relay with any suitable coil voltage would have been more than adequate.

[@ThatEgghead]

David Chuang and some sort of safety device - fuse, PTC thermistor, etc.

[@TheMetalButcher]

Yeah they literally make water heater controllers for cheap.

[@user93237]

But why would a mechanical relay be better? You're only saying that SSW's strength lies in fast switching, which does not imply that it should not be used in slow switching applications.

[@Anonymouspock]

okorok Simple, very simple. It has a continuous coil current but no voltage drop problem. So they can switch large currents without heating up due to that current.

[@kamyarghofrani]

Mechanical relays have a much higher current rating/higher efficiency and are generally much less expensive.

[@ClairdACDC]

Actually Matthias the more I think about this the worse it gets. You are a very knowledgable guy and a youtube star but this is just plain dangerous. In your build video for this you mentioned the ÿoutube safety experts" and had a sarcastic comment. I am and electrician from Australia and cringed at your original video. No earth on the mounting plate, crap wiring, limited protection and the wrong type of device for switching and holding in the current of a water heater. People think that Electricity is easy but seriously you could have burned your fucking house down to save a few bucks. Stick to the woodwork ( which you are excellent at ) and we qualified electricians will do our stuff............... ( p.s you probably wont read this anyway )

[@knucklecorn]

I agree 100%.

[@vedranlatin1386]

Other then this one probably being a fake, what have you got against SSR switching a heater?

[@vlogerhood]

Well for one thing, is it rated for continuous duty at that amperage?

[@ClairdACDC]

The amount of misguided switching capacities with SSR's are endless. They say "50a" but after they blow up you realize that the 50 amps was an AC7 rating ( light domestic loads ) Contactors on the other hand are tried and proven to last up to 1,000,000 operations and if he had used a 3 pole contactor that costs about $15 and wired all 3 poles in series there would never have been a problem.

[@davidwootton683]

bigclivedotcom took one apart on his KZbin channel. Worth watching! He had the same type rated at 10 amps and no more.

[@douglanglois456]

Kudos to you for publicizing the failure, and not just brushing it under the carpet. But I guess the "safety know-it-alls" have a point sometimes, eh?

[@gardnmi]

Let's hope the folks that watched the first video and implemented your idea see this video too. Reading the comments in the original video someone mentioned that these knockoffs tend to catch fire....lol.

[@srmofoable]

I also warned of the dangers of those knock off Foteks. They're great for some experimenting but there is not a chance I would leave one hooked to mains unattended.

[@thebeststooge]

SrMofo Exactly. He was lucky this time but next time it may burn down his house. I do not trust their DC SSR for the same reason because, typical of the Chinese, they claim an Amp rating but you better halve, a third, or a fourth of their number to get a margin of safety. Spend the money for a real one (they are expensive but for a reason) as life is too precious to screw around with like this. edit: My other concern/rant was him using axle grease as a TIM. Seriously? That was adding on to a future failure and he, and I, had a few words about it. It worked didn't it? Was his main thing while mine was "It worked for now but it is not a TIM and not meant to be." He did two stupid things but luckily it did not cost a life/lives/property this time.

[@MazeFrame]

TO-220 is not a lot of surface to sink away the heat. After one of those blew in a setup, I bolted the next one to an old Intel heatsink (one of those with copper core) and that fixed it.

[@ZenMuff1n]

wow. you're brave. I usually don't go over 2/3 of what the spec sheet says something like this can take.

[@Yonatan24]

...But how are you (me, inexperienced) supposed to know when not go over a rule like that? I bought a cheap Chinese high-speed 10A PWM dimmer for my homemade LED lamp, but it heated too much at 6-8 amps. so I glued two heat sinks to the tiny heat sink they supplied. Works perfectly.

[@bborkzilla]

I wouldn't trust those generic Chinese parts for anything.

[@ZenMuff1n]

It's half for super cheap stuff and cooling is a requirement. I know what dimmers you e talking about, and I burnt 2 of them making a stable system with remote controls. Nothing cheap chineese likes heat it seams. The rest(like trusted brands) it's 2/3.

[@TobyCowles]

If it is no name then I don't go over 1/3, if it is a made by a good known brand then I probably wouldn't go over 3/4 for something as high power as this. But all this stuff is just rule of thumb, all of the manufacturers have different quality standards and you never can be too carefull.

[@jameskelly1680]

Even if this was not imported from China, he is running 22A on a 25A device. NEC standards in the US say that you should never go above 80% in continuous use. This is 88%.

[@JamesBiggar]

I've had trouble with this brand before too (yes folks, with a proper heat sink).

[@danmorphis7759]

James Biggar the ones you find on eBay/AliExpress are actually counterfeit. Real ones cost about $40/ea. The UL even has a warning on them.

[@ScottPankhurst]

Fotec are OK. it's the fake ones that are the problem.

[@richb313]

I have used these for many years in Industrial Applications with little problems. We mainly use them to energize motor Contactors and the like when using Programmable Logic Control Applications.

[@jmsaltzman]

If it says "Fotec" or "Foteh" it's probably not legit :)

[@Dirk3672_StupidYT]

FauxTech - legit, eh?

[@yorgle]

I've found that spraying some isopropyl/rubbing alcohol on charred boards like that and a light scrub with a toothbrush makes it much easier to see what's happened after events like this. :}

[@Havreflan]

The safety-know-it-alls saw this coming. You got lucky.

[@dieselscience]

Yet for some odd reason NONE of them will call it what it is - cheap Chinese crap.

[@sssiod]

I would have installed something like that in a Hoffman type enclosure. An enclosure is not really made to keep people out but rather contain the electronics. In a failure such as this there is not much risk burning things down around it from inside a metal box.

[@JeffDM]

You're supposed to use a heat sink at those current levels, a thin plate of metal doesn't count. The one usually sold for that looks like an inverted tree. Also, Fotek SSRs are known to be fraudulently relabelled at a higher amp number to fetch a higher price. UL has a web page to help you spot the authentic ones.

[@JohnBurgessMusic]

I would never use those cheap ebay electrical components in any high power or safety critical application. Doesn't even matter what the datasheet says for that TRIAC and it's current handling, there's no reasonable guarantee that it's a genuine part, or it could be a factory reject. A certified mains rated mechanical relay from a reputable supplier might cost a lot, but it's cheap when you consider that it will be switching high power loads, in your house, and largely unsupervised - probably while you're sleeping. Scary stuff if it goes wrong.

[@antalz]

Anything that I plug into the mains or runs unattended has to come from a reputable european shop for me. My projects involving mains power all run on Mean Well power supplies. That small risk of burning your entire house down isn't worth it.

[@eksine]

fotek is a chinese knockoff clone, you were foolish enough to not know that. for example their 25 amp relays are actually 12 amps meaning you should not run it for more than 10 amps. theres a teardown video you should watch it

[@SuperGrover]

I've never had luck with the solid state relays in those situations. Good old school oversized mechanical contactors for the win...

[@gordonlawton8815]

Best practice is to use an SSR for fast switching applications and always to put a mechanical contactor or relay in series. This serves to isolate the power if the SSR fails as they fail closed. You should not use an SSR by itself regardless of the quality. So the safety issue is the result of poor design not just poor quality.

[@lordofelectrons4513]

It appears the problem is the lack of adequate heat sinking of the relay. I do not see thermal compound on the relay plate. this is necessary to greatly improve the transfer of heat to the heat sink. Any small air gap say 0.001" is a problem. Also the metal plate you are using appears to be steel. Not the best material for conducting thermal energy Aluminum is much better by about 4 X. The idea is sound but execution was lacking, use a big aluminum heat sink with thermal compound between the relay and sink, make sure air can move freely around and past the heat sink enclose the relay in a metal box to protect against fire and having exposed voltages.

[@kittyfanatic1980]

You put WAYYYYYYYYY too small a heatsink for that SSR. For a 30a load (what most water heaters pull) you need active cooling or a radiator system.

[@stefantrethan]

I'm just glad that deathtrap is gone and nobody got hurt, you were lucky the fire didn't spread. If you look at the size of the heatsinks that come optional with these relays to achieve their full rating (well, not the chinese ones but proper ones) you know why this was bound to fail.

[@_cb336]

Yeah, right on, brother. Deathtrap were never the same after that first album.

[@pedrobravo6972]

Hi, this is not a product failure. It is a problem of your installation. The problem that happened to you was not to place a heat sink, as the specification says. If the circulating current is greater than 20 amps, you must include a fan.

[@randycarter2001]

I didn't get a close enough look at the Fotek relay you used. There are a lot of fake units on the market. There is a web page posted by an official agency devoted to identifying the fakes. The fakes are made with parts that are nowhere near the ratings on the case. www.ul.com/node/81246

[@x_ph1l]

I've disassembled bunch of those solid state relays from different ebay sellers and found that 100% of triacs are grossly underpowered (12 - 16A, while relay is rated for 25A) and some of the relays had clearance issues, meaning that if some surge condition would happen - the relay will disintegrate, just like yours did. My advice - don't use those cheap SSRs from ebay, buy them from Digikey, Mouser, etc. (yes, they will be much more expensive).

[@Unaboner]

I had the exact same experience. Took apart a cheap eBay 25A rated SSR and found a 12A triac

[@nicktohzyu]

why not just use a mechanical relay

[@matthiasrandomstuff2221]

couldn't fine one at the time. Didn't realize they had quite as much voltage drop (some DC ones I used in the past had much less drop)

[@g.z6161]

the datasheet says that you need a heat sink after 5A and a fan at

[@jmsaltzman]

There are many, many counterfeit Fotek SSR's for sale online :( To say the issue is Chinese SSR's is not accurate: Fotek is a Chinese company and makes great relays.

[@ianjefferson9518]

I belive Fotek is Taiwanese. Indeed these fake controllers work but only at about 1/2 or 1/4 their rated current. One issue I encountered with 40A fake foteks is that they fail in the on state so regardless of signal they pass current. Same application as Mathias's - immersion heater. I have used these quite successfully for up to 1500W ( 10-12A) heater circuits but at 4800W (20-22A) they fail on. I have a rainbird relay purchased from a slightly more reputable supplier and it works fine at these loads.

[@jmsaltzman]

Ah yes, Taiwanese, my mistake. Seems like de-rating the SSR's by more than half is a good idea! A colleague recently ordered a few for cheap, and they came with "Foteh" on the SSR's labels, in non-branded packaging :|

[@OldCurmudgeon3DP]

@@ianjefferson9518 I have Inkbird brand 40A on my project. 4500W @ 240V so about 1/2 of the claimed rating. Heatsink that came with it is the size of your fist. The enclosure has forced air circulation. I've checked after 10min operation and the hottest spot was about 100F. I used cpu thermal paste before bolting on the heatsink too. So far the only runaway was due to a failed MCU. Left the mechanical thermal safety cutout in the mains just in case; to prevent a ka-boom.

[@petermuller6923]

Wow, that cheep Chinese SSR lasted for 4 months at 88 % load running for longer periods of time dayly? Not bad. These Chinese ratings are very optimistic and i would not ever put more than 30-50 % load on these 4 $ SSRs. Sometimes, Chinese manufacturers label 12 A ones as 24 A SSRs. You should also never use a high quality SSR on nearly full load in continuous use. For 22 A, i would always use something in the 40 A range.

[@petermuller6923]

Wow, thank you for confirming my own experiences and what i have seen at BigClive's KZbin channel. I had not thought, that you even get a 4A Triac in a "60A" SSR. You absolutely never know, what's inside unless you take it apart and destroy it. That is unbelievable... A fireproof box is a must-have for these ones. A really good idea. Never switch loads with an SSR, when the load running forever may burn down your house or destroy something valueable. Almost everytime, an SSR fails, it will get continuously conductive and the load will stay on forever. Lights are not very critical, but heaters or motors in some applications.

[@patpalermo7629]

Bigclive did a teardown on one of these. turns out the triac was only rated for 12A. That's why I bought the 40A version - hopefully it will handle at least 15a

[@girder123]

Just buy a quality product from a reputable distributor, add some safety margin to your application and you'll be ok - no need to risk your life and property with cheap ebay crap

[@kadmow]

Was that a genuine rated 25A SSR, or a cheapy off ebay (underrated) ??

[@g.z6161]

that was a fake you can see it says made in Taiwan instead of Taiwan made....

[@zinckensteel]

I saw the aftermath of this exact same failure in a piece of lab equipment - in the same semi-clean room as a mass spectrometer used for C-14 analysis.. ..those were some very stressed out biologists.

[@yamazakirichard767]

Thanks for posting your failures for us to learn from. This is something I have wanted to try myself but won't.

[@donaldasayers]

Most "Fotek" SSRs are fake, particularly on Amazon or Ebay. The only way of buying a good one is direct from the manufacturers. One Tell is that the real ones say "Taiwan made", and not "Made in TaIwan".

[@mr_spud_nugget3723]

looks like a job for bigclivedotcom :P

[@galacticovergrow]

He would have to find one at the pound store first :P

[@nukularpictures]

I really dont understand why you didnt fit a thermal fuse and a normal fuse along with this ssr. I mean of course the choice of that really was poor but it would have been much safer if you would have something limiting the power if it fails. I would recommend of using a high quality ssr in series with a fuse and a thermal fuse. Also a propper heatsink would be required. If you would want to do it neatly you should also put it all in a nice fireproof enclosure and then it should work for ages without having that problem or risk ever again. For me saving those few dollars in the installation wouldnt be worth the risk of my house or family. And if lets say 100 dollar for a proper installation is too much then I'd say it is not worth it anyways. Not for the risk it creates.

[@briandyck4637]

Whenever I have to use a relay for something, I usually use a magnetic type relay with a rating at least double the rating of the load that it’s going to be switching.

[@Umski]

From experience, triacs dissipate a lot of heat - approx 1W per Amp - I have a BTA26 triac (self made SSR) which switches anything from 1W - 2900W (0-13A@240V) into a water heater but it is fully variable, not just on or off. I noticed that when it was constantly running at full power (solar PV diversion) it started to do weird stuff as ambient temperatures crept up - measured it with a IR temperature gun and it was hitting over 100C on the heatsink - far too close to the junction failure temperature. Re-calculating the size of heatsink, I went from 3.1W/C to a 2.7W/C (twice the height) and it's been fine since (I even considered forced cooling with a fan at one point!). For your example, I don't see the point of using 'complex' electronics for something which is either on or off for a long period of time (minutes/hours) - there are too many points of potential failure - personally I'd stick with a relay/contactor arrangement for purely on/off switching. Glad to see it was only the casing that melted itself however and not anything else nearby :o

[@dasstackenblochen9250]

Well it is a 3 $ SSR after all... also SSRs *need* surge protection and pre-fusing when connected to mains. That might have prevented this spectacular failure, or limited its impact. 20 A on a 25 A SSR is also really pushing it - no way you can get the required thermal resistances with just that small heat sink.

[@mauriziofigini]

bigclive?

[@marcoschwanenberger3127]

I don't think even Clive can analyse anyhting of this mess.

[@mauriziofigini]

exactly, he would try to blow up the other one straight away!

[@matambale]

In the video "Teardown of an eBay 25A Solid State Relay. (SSR)" (at five minutes into the video) Clive shows that the triac used is actually only rated for 12A.

[@TheGlen1985]

I was thinking the same thing

[@thechumpsbeendumped.7797]

So glad you and your family weren’t hurt. Best wishes from Britain.

[@tommays56]

We use SS relays all the time and one that size actually needs and epic fined heat sink with good air flow to run remotely close to its rating

[@Elaphae]

Very glad that you did not have a house fire. 🔥 Interesting tear down too. (Ever watch Diodes Gone Wild?)

[@alfredneumann4692]

Nearly 5 KW switch power...... i never would use a solid state relay for such a hammer. And this little thing made 50W heatpower? Never. Perhaps with a good heatsink and a fan.

[@mildyproductive9726]

I think probably more like 40W. But that is a proper roasting for any component in an enclosed box with inadequate heatsink. I think 2W will make a bare TO-220 boil water.

[@accountshanahan]

Wow your a brave man using that in your house! Lucky you didn't burn it down. For the loads involved with a water heater I would have that relay operating the coil on a contractor and let the contractor do the heavy switching on the heater circuit. (Don't know if a contractor is a thing in the US, in the UK its basically an industrial type relay with failure protection and a much bigger spark gap so they can be rated to very large loads). Love the channel and good luck with the house move

[@kwad3d10]

What would you suggest to switch on a 350w power supply? I could be left on for months at a time

[@STONEDay]

Here in Canada if a non-CSA approved electrical device like this burns your house down and the insurance company is able to prove that is the case then you're not likely getting any cheque from the insurance company!

[@eclsnowman]

That brand is completely garbage and dramatically underbuilt/underspec. Not the first fotek fire I have seen. Search KZbin... You will find teardowns that go in more depth with how bad it is.

[@superraptorproductions5452]

OMG, what were you thinking? you could burn down your entire neighborhood!! Let's all of us just stick to the safety of social media and our smartphones.

[@rivernet62]

So you still have a functional one? Try to replicate the failure! On camera!

[@TheRainHarvester]

Mark Jones yeah, make a video, Mathias!

[@MrFaaaaaaaaaaaaaaaaa]

Did you use wires in screw terminals? I have seen screw terminals burn up because they were used with wires instead of proper ferrules on the end of the wires

[@railgap]

Well this is embarrassing. You did not read the SSR's application notes!! _ALL_ SSRs require a whacking great heat sink - literally, the size of half of a shoebox - big - to live for very long. Hint: THE HOT SURFACE OF A WATER HEATER IS NOT A GOOD HEAT SINK! I laughed out loud and probably woke up my wife and my housemate. And yes, smart people rate stressed parts conservatively instead of right up against the stated limits. You asked a 25 amp relay to pass 22 amps with no heat sink at all, what did you expect would happen? You left yourself no wiggle room for something to go wrong. "I didn't know it needed a heat sink" -- well why didn't you know?? Do you always set about new and potentially dangerous tasks without educating yourself first? Do you? Really? READ. THE. DOCUMENTATION.

[@andrewbieger5004]

Maybe I am missing something about what you were trying to accomplish. Why go with this electronic switch when an old school mechanical clock type HWH timer works fine? My timer (all 220volt) has been running for 25 years, switching a 4500Watt element, with a one hour "heat" in early morning and a 2 hour "heat" starting at 6PM. The pins lock down on the clock wheel, and I have infinite adjustment for on and off cycles. The internal contacts on these mechanical units, just like those on a pump clock or pool pump relay are rated for plenty of amps, and you can't beat the cost, based upon its life cycle. I am glad the electronic unit didn't burn your place down. Old school works just fine, IMHO. Good luck with the move.

[@OregonDARRYL]

Rumor has it that the fakes should only be used at less than HALF the rated amps... and only under supervision. Don't turn your back on these things...

[@aksting]

These type of solid state relays require a good heatsink unless your using < 50% of power depending upon ambient temperature and % ON time. The steel sheet metal is a poor heat sink. You should have used a 50 amp SSR with an appropriate Aluminum heatsink with thermal compound/pad. Better yet, use a contactor.

[@AL6S00740]

Told you so on the last video, INDUCTIVE LOADS ARE NOT SUPPOSED TO BE CONTROLLED BY SOLID STATE RELAYS, you are very lucky that it didn't burn your house down, just wood and insulation..... Being reckless with systems that alnways online is stupid and dangerous. You set your wife and kids in unnecessary danger. Period think about that...

[@danflurry]

This is why we need to go back in time and STOP BEN FRANKLIN.

[@Rachotilko]

Much more likely explanation: a lightning surge. According to the datasheet, the SSR is rated to withstand 600VAC. However, in case of current/voltage surge, the voltage will inevitably rise much higher in case no protection was in place (GDT, MOV, TPSD).

[@BeachsideHank]

Anything electrical from China I use a 0.5 multiplier against their published ratings. ☺

[@movax20h]

That is why you avoid cheap SSR from ebay, China and Futek. The main problem with Fotek (Taiwan) is that there is actually a lot of fake / counterfeit ssrs around from China. Recommeneded: Crydom, Omron, Ametek, Opto22, Weidmuller, Sharp, Altech, Carlo Gavazzi. There might be more, like Panasonic, but who knows. And buy via trusted distriubutor, like digikey for example. Seriously, anything that can go into flames when you are not around should be of highest quality. But honestly I think you failed to properly secure cables, or the screw terminal connectors corroded or are of poor material, and they started heating up. Also, it is likely mechanical relay would be better here. Unless you need switching off and on every few seconds, go with relay.

[@nathantinlow4769]

Build a bandsaw out of wood: That's crazy talk, it won't be strong enough, it'll never work... Build a fan impeller for a dust collector out of wood: Foolishness, it'll just blow itself apart!!!... Use drawer slides for the pantorouter: why bother, it's too hard, you can buy roller bearings from china (won't work as well, but much easier...)... Use a SSR to turn off the water heater: Nonono, you can't use a device designed to switch AC loads to actually control AC loads, it'll blow up!!!... I guess if you have enough monkeys writing comments on youtube, you're bound to have success once in a while... Look people, the only mistake he made was trust the rating on this SSR which turns out to be bogus (bigclive has a video on a similar SSR from the same company). Lesson learnt (and thanks to his sharing this video, lesson learnt by a lot of people! I applaud him for having the courage to post this video)... If you are somebody that "does", then you will make mistake: learn from them and move on... If your whole purpose in life is to avoid making mistake, then make sure you stay in bed and keep hiding under your covers (and please refrain from commenting on youtube... it could be dangerous, somehow)... As for Matthias, THANK YOU for the awesome youtube channel!

[@FlyingShotsman]

Some have suggested that FOTEK are knock-off SSRs. They do bear a broad physical resemblance to other "block" type SSRs, but they're not knock-offs. FOTEK is a Taiwanese company that makes a wide range of industrial control products: www.fotek.com.tw/index4.asp It may not be a knock-off, but the specific SSR used in this instance is the subject of a UL notice about counterfeit UL recognition markings: www.ul.com/newsroom/publicnotices/ul-warns-of-solid-state-relay-with-counterfeit-ul-recognition-mark-release-13pn-52/ The danger of using dirt-cheap Chinese electronics, *particularly* in mains powered applications, is very real. The Chinese *routinely* advertise fake product specifications that grossly exaggerate their products' capabilities, use black market components and apply counterfeit safety markings. The super-low prices are so tempting but for something being installed in your home, it's just not worth the risk.

[@randycarter2001]

Where did you get the SSR? Many of the SSR's less than $5 are fakes. Google "fake SSR" for a wealth of information. There are several SSR autopsy videos on KZbin where the label says 25 AMP but the part inside is 12 AMP or a 40 AMP unit with 16 AMP part. Often the internal isolation barriers are inadequate as well. Only buy SSR's from reputable sources.

[@hellterminator]

These eBay fake Fotek SSRs use the BTA25 triac (well, some use the BTA15 and push it way past its rating, but that's another story). If you look up the datasheet, there's a diagram of power dissipation versus on-state current. At 20 amps the power dissipation of this relays is ~25W. Do you know how big a heat sink you need to passively cool 25 watts?! Not only you didn't use _any_ heat sink at all, you installed it on top of a water heater where the ambient temperature is even higher! If you did 10 minutes of research, you'd have seen this coming a mile away. You're very lucky your house didn't burn down.

[@AlienRelics]

1. 25A for 22A? Too close for my comfort. 2. A thin sheet of aluminum is not much of a heat sink. 3. Sitting on top of the hot water heater means ambient temp is going to be a bit higher. 4. Summer in a garage is likely to get hot. Looking at the datasheet for the Fotek SSR-25DA: cdn.sparkfun.com/datasheets/Components/General/SSR40DA.pdf Current starts derating at about 82C (see page 12). But look at the size and configuration of the heat sink required for a 25A SSR, it is 100mmx100mm with lots of fins (see page 13). That will be with lots of free air, preferably mounted so the fins are vertical or with some forced air flow. Even with a large heat sink like that, shrink it to 50mmx100mm and the datasheet lists a max of 10A. With that aluminum plate, I'd be surprised if it could handle more than 5A for a length of time. I think this could have failed purely due to the inadequate heat sink, made worse by elevated summer temperatures. Add the possibility of counterfeits in, it was doomed to failure. There is a reason SSRs come with four bolt holes and a wide, flat aluminum base. And a reason manufacturers use these large heat sinks on them, and don't forget a thin film of thermal paste: sc01.alicdn.com/kf/HTB12s_2KFXXXXbqXXXXq6xXFXXXM/aluminium-led-heat-sink-radiator-heatsink-heat.jpg

[@andrew9365]

Get ahold of uncle bumblefuck and have him do some destructive testing on these. For science of course. Very interesting failure though.

[@arthurmorgan8966]

3D printing community uses these relays for mains heated large printer beds, almost always attached to thermal fuses for thermal runaways.

[@amundsen575]

the fake SSR only has triac rated for 12A, which should be de-rated to 25 to 50% for actual use, about 5A . for a 22A load you need a Real 50-80A SSR with an adequate heat sink. a real 50A SSR purchased from a real supplier like digikey costs $50-100

[@paulkolodner2445]

It looks to me like the grease didn't make contact with the mounting plate, although it's hard to tell from the video. At any rate, that plate was not in very good thermal contact with anything else. You even mounted it in a convectively stable manner, heating a horizontal layer of air from above. You knew at the outset that the heat load was substantial - 50W - but you did an unprofessionally poor job of thermal engineering. You're lucky you didn't burn the house down.

[@JasperJanssen]

Paul Kolodner also, grease isn’t thermally conductive in any meaningful way. The whole setup was basically just stupid. And the dig at “KZbin safety people” is particularly ironic given the results. That it worked for a little while clearly doesn’t mean it’s safe.

[@paulkolodner2445]

Well, normal grease is not as conductive as, say, thermal grease, which is loaded with ceramic, metal, or graphite particles. But it's much more conductive than air, which is what would fill the tiny gaps between two plates that are clamped together without grease. So the use of plain old grease here was not a gross error. But a thin horizontal layer of air which is heated from above - exactly what was encountered in this setup - is convectively stable; ie, buoyancy does not cause the air to circulate. A motionless layer of air is literally the best insulating material you have in your house, aside from vacuum, should you have any of that lying around. By mounting the relay this way, Matthias produced the worst possible situation as far as cooling is concerned. The first lesson here is: if you are going to make a gizmo like this, mount it with the heated surface on top, or vertical, so that hot air can rise and provide cooling by what is referred to as natural convection. You might still need a fan and/or a heat sink with fins. The other lesson has been pointed out by other commenters: don't trust current ratings. In fact, I have seen this failure before, in my air-conditioning system: a circuit board with a mechanical relay got fried because the wiring traces couldn't handle the current.

[@uwepolifka4583]

22A for a chinese 25A SSR ist ways to much. 25A ist the theoretical max. possible Current. And it needs a BIG heatsink. When anything went´s a little bit wrong the SSR turns into a lighter. Here is a video from Bigclive about this SSR. He found some errors. One is that the input becomes to hot at max. input voltage. kzbin.info/www/bejne/eqmomaugq86Zr7s

[@chimaeria6887]

I'm pretty sure BigClive tested one of those knock-off Fotek SSR before and they actually are rated for about 12A, not the 25A they claim. If you had bought a real one, i'm pretty sure nothing would have happened.

[@Greebstreebling]

I had one destroy itself, mine was a DC version switching 12V, switched by a microcontroller. It melted badly, so I made my own using two MOSFETs as a low side switch.

[@SilvaD702]

Instead of using a knock-off ssr, you should have use a contactor for this purpose

[@mimic58]

I bought the 100Amp version of this SSR hoping it would be able to handle a 10amp load , I set it up on a test bed with supplied heat sink fitted properly with thermal paste, after just 13 minutes i decided there was no way id be trusting it - SSR's can be extremely useful with items that have load arc but do spend the money and buy proper ones - These chinese knocks offs are basically fire lighters.

[@theUBERKron]

You need to learn chinese. 25 amps will have transistor rated 15 amps. 25 amps is the smoke point. I buy/sell generators. 8000 chinese watts seems to equal 5000 actual. Its becoming a problem having to over/derate things based on their origin.

[@edwardbadlands8621]

Wow that is some fine UL approved Chinesium .... will the homeowners insurance policy cover the use of something bought off China Taobao? (that is to be taken sardonically and sarcastically)

[@skaterzero807]

Reposting my comment from the previous video on this: "FYI, the SSR may be a counterfeit and only rated to 12 amps, see article here: protosupplies.com/inferior-counterfeit-fotek-ssr-25-solid-state-relays-on-the-market/" It's a shame that these scammers are labeling fakes with way higher ratings than they actually can handle and are putting people and property at risk.

[@aaroncameron1494]

I am going to go ahead and get this out... "Yo this channel is lit "

[@galacticovergrow]

The cheap Chinese knockoff solid state relays are usually way over rated. I bought a couple from eBay and the triacs were only good for 15 amps when the solid state relay was rated for 40 amps The legit solid state relays I bought from Mouser were much better, I could not even disassemble it because it was potted in Epoxy

[@12345NoNamesLeft]

My brother did the same thing and had the same experience. He went to a way over rated traditional relay pair and it lasted longer but still failed. He then got a good deal on a 40 amp DP industrial control timer and it's still working rexel-cdn.com/Products/Intermatic/T101.pdf?i=4E6960AF-791A-49F5-971E-E630F0743F21 22/25 is 88% load - usually the 80% rule applies Heat sinking has to be better to reach the rated load on those. I most often see full size finned aluminum heat sinks on those.

[@davidwootton683]

bigclivedotcom took one apart on his KZbin channel, it is worth watching.

[@cooperbaker]

I had the same problem. Fake fotek relays. My relay failed in the on state with a 20A load. Toasty. I left a warning on amazon but the product listing was removed. Replacement NTE relays have not failed yet.

[@slamdvw]

Gotta love cheap chinesium... only thing I would have done different was to put it in a metal enclosure.

[@winandd8649]

I had a meltdown too on a cheap chinese fake "Fotek" SSR, and it not even touching it's limits (about 1 amps at 230V) Beware for those chines ones

[@beyonddeath123]

Had these fail too, only use name brand SSR's now and havent had an issue since. Crydom or Omron are ones I've had good success with, but 20-30$ cad for one.

[@richb313]

Actually more likely is that because we are in summer months the odds of a Brown Out increase due to increased loading on the grid because of Air Conditioners. The Triacs used in those SSR are quite robust and can easily absorb brief surges but if the voltage drops all bets are off. A safer way to have controlled it would have been to use the SSR to control a contactor with a 120 Volt coil.

[@thedavesofourlives1]

The internal components have a limit of 16A according to a teardown of a 40A Fotek relay by GreatScott: kzbin.info/www/bejne/aIbXfWWrdr52i6M

[@gondala]

well, I think in this example it is showed how important to make automation system. I mean, it should have used the current limiter to make sure the current will not over 20 Amp. It is also important to add temperature sensor near the SSR to detect if the temperature is higher than it should be. If those two things happen, then the system will turn off the heater automatically and an alarm is turned on (before the SSR is failed or burned).

[@dangerdavefreestyle]

Well the world would certainly be boring if everybody was the same, so to each his own, however I could never make sense of showering in the morning. Time flies and its hard enough getting breakfast going. Then you work all day and get sweaty and nasty, so do ppl go to bed like that? I like to hit the hay nice and clean, and its not like i'm getting sweaty overnight, so when I wakeup i'm still clean.

[@JustinAlexanderBell]

You're supposed to use these with a properly rated heatsink.

[@Cheese_1337]

He had screwed it to that thick sheet of iron tho.

[@kcutoob]

@@Cheese_1337 Nowhere near enough heat sink. For a 25A rating, 23A requires a very large heat sink with fins, and probably a fan. Look at a datasheet, and application notes, the heat sink requirement is not trivial, he needs to dissipate over 74 watts - that is a LOT of heat. A top quality brand would not have survived w/o a proper heat sink. Sorry, but Matthias did not design this correctly - stick to woodworking!

[@thehighriseconstructionob9679]

Those triac inside is downgraded amp other videos show break down of what's inside ,they lied amperage rating so need higher amperage rating sir . Other dc to DC relat has down graded transistor too and burned up its common to made in chaina MPPT, Relay, charge controller, SSR

[@meesternadim]

Shit, I have one of those in my 3D printer. Should I be worried?

[@kayzrx8]

Just get a mechanical timer for water heaters at your local hardware store. These SSR can only meet spec rating with a decent amount of thermal control with a heatsink and fans . you got lucky that's all that happened. At the very least you should have put the thing in an electrical enclosure. This is terrible design and Engineering and you will get someone killed .

[@dumle29]

Yeah that's about what I'd expect from a china clone SSR. You sadly do get what you pay for with this sorta stuff :/ If you want to set up something similar in your next place, then I'd recommend going with some quality SSR. Something like crydom, or omron. An example of a suitable combo would probably be an HS251 (heatsink) + D2450 (50A SSR). They sell this as a combo called HS251-D2450. I'd get it on arrow.com, mouser.com or digikey.com, but expect to pay around 80 USD for it :/ Because your load is very periodic, you may be able to get off with getting just the heatsink and a D2425 SSR (25A SSR), and that'd land you more around 45 USD

[@dumle29]

You can use octopart.com to check which place has the parts cheapest

[@jordanbrewer191]

MATTHIAS! HOW DARE YOU POST A VIDEO ON KZbin!? YOU COULD HAVE SERIOUSLY DAMAGED YOUR FEELINGS!!! I HOPE YOU LEARNED YOUR LESSON!!!.......>.>

[@tiger12506]

Everybody on here pretending they don't have burnt spaghetti under their stove top burners. Yeah maybe it could have been a bit better contained, but no sense in jumping straight to the licensed technician bandwagon... Keep on experimenting Matthias!

[@sejlefrew]

There's a rule electricians live by - Never Ever Ever Surpass 80% of the stated load rating on any switching equipment.

[@edthedaddy]

you should be using opto 22 SSR. guaranteed for life. next question. why use this? no demand charges for residences.

[@AtlasReburdened]

Electronic component ratings are the MAXIMUM rating before failure. You wouldn't drive an axle rated to shear at 2000Nm at 1800Nm cont. load that has a startup surge like a cold heating element does. My general rule for ratings with relays is if you want assurance that it will get the job done you de-rate a component by 25%, if you want it to last a few years you de-rate your component by 50%, if you want it to last for the foreseeable future you de-rate by 66%. Put another way; Fast job: ComponenRating = SurgeCurrent x 1.25 A few years: ComponenRating = SurgeCurrent x 2 Foreseeable future: ComponenRating = SurgeCurrent x ~3 And you should calculate SurgeCurrent by measuring the resistance of the element while cold and dividing your mains voltage by that number in Ohms instead of using a clamp meter to measure it in operation. Solid states don't need contact ware considerations so for your application I would slap a 60A version of that same SSRelay on and call it pretty good.

[@AtlasReburdened]

Oh, and mounted on a thin piece of galvanized steel isn't the best idea ever, but if you properly de-rate your components you could probably get away with it.

[@thehighriseconstructionob9679]

Is this from Missouri solar & wind ? My Chinese mppt regurator catch on fire too horrible.it almost burned up my house. I need to know where you bought it so I don't burn up house

[@russellhltn1396]

Let this be a lesson. Cheap Chinese stuff is fine for playing around on the bench. But to "for real" - you want name brand stuff. Not unless you're trying to collect on insurance.

[@Fuogor]

What's this? A bit of BigClive on Matthias Wandel channel? Just by the title I was expecting it to be a Clive video.