DIN rail mounting surge protector with uninspiring safety device.

[@Samoasoa]

The phase line is usually coupled with an external circuit breaker like a fuse or a MCB. If the surge voltage is big enough it will allows a large current to pass thus shorting to the earth line. In such case it will blow the fuse or trip the MCB. The solder melting away is like fail safe of last resort in case of external circuit breaker failed to work.

[@phils4634]

I took a failed one of these to bits some time ago (made by Weidmuller). The interior design was very similar indeed, with the exception of the "solder blob" which in their case seemed to be sintered fusible disk. Worked on exactly the same principle though - once the MOV had absorbed too much energy, the internal resistance dropped (pretty abruptly), and the high current caused the fusible link to, well, fuse.

[@jamesbrown4092]

"Its partner nail here... I recently jammed a bit of circuit board material up the end of it. That was just not nice." I LOVE your talent for understatement.

[@jamesforte-mason8849]

Hi Clive, a guy I know asked me to look at his little arc welder, 230v jobby, nothing fancy, just for a bit of DIY stuff. He had an issue with it keep cutting out so he took it into work one day and modified it by putting a low voltage PC cooling fan in the back to keep the transformer temp down a little bit better and apparently it worked. Only after several months (not using it much) the fan died, it was a 12v fan with a mini controller. He replaced it and carried on using it. I borrowed it the other day and he showed me it working before I took it away only to find out the fan had died again. I metered it out and actually it was the controller I think as its the first thing before the fan to go. I used it anyway and when I returned it he said to keep it as hes buying a better one. I took it apart to look at the cooling fan issue again and the controller has in fact gone, must be the transformer surge during striking the arc I reckon. So my fine fellow, can you advise please, is there such a device that is small enough to wire in line (or across the fan terminals) with the new cooling fan that I'm going to fit to absorb the surge? I'm going to fit a 230V fan this time, I dont think the cheap Chinese backstreet electronics has a place inside a welder. There is hardly any heat actually after about 20mins use, I was suprised how cool it was. Hopefully your wisdom will alleviate my issue, thanks 👍👍

[@bigclivedotcom]

You can get compact 12V power supplies. The 12V fans are more compact and quieter.

[@AutomotivEivind]

What a coincidence that this video was just released, the day after the surge protector in my house blew again. It's about five years since last time, and then it was five years since we had it installed. I just learned about these holder-and-insert-type surge protectors, and that is definately what will go in my consumer unit this time. I can confirm the slot/peg is for indication/warning when something is wrong. In my box there is even an audible alarm hooked up to it.

[@andycrane7126]

I have tonnes of these at work. I'm a engineer at a switchgear/circuit protection company. Ours are very similar and around 5-10 years old. The current market have a lever pull cartridge design. Let me know if you'd like some samples to "test". Keep up with he good work BC

[@petrosrz8990]

You mean the Phoenix contact ones we use everywhere at my company ?

[@FerralVideo]

That "little green pip" is a mating/keying system. These MOVs come in a variety of voltages, and the pip makes sure that you can only insert an MOV of the correct voltage rating. Ex, you wouldn't want to install a 175v clamping module into a system with 240v service.

[@pierreuntel1970]

No it's not, the keying is another thing but this one is an indicator, I have one that have a 3 prong terminal under it which can detect if the thing is tripped, there should also be a microswitch behing that pip on the supported base

[@Markus0021]

I also loved the comment "its got a metal tab.... well, it *HAD* a metal tab." Made me chuckle.

[@LaterMeansBrick]

I love how the varistor is encased in brittle resin that breaks of in big chunks. Makes things more exciting when it fails :)

[@animarkzero]

In my country these surge protectors are required in a new installation. For a three phase mains household distribution supply they cost about 100-150 Euros. The main reason to have them is indirect lightning strike that induces high voltages into your circuit.

[@Kletterhaus]

Animarkzero ‍ ‎‎ arent they mandatory everywhere? You normally have a surge protector where the Electricity comes into your house.

[@stareclipse2001]

Works as it should. In case of a surge spike the varistor becomes conductive and will trip the RCD. If the varistor got too hot, the indicator will show that you need to replace the protection. Even Legrand, GE, etc, use the same kind of element.

[@deltab9768]

I’m tempted to buy one of these things, and subject it to sustained over voltage (say, with a 3kVA 240->480V transformer.) I can’t quite tell whether it would eject flames, metal parts, or a mix of both.

[@ChristianRX7]

Looks similar to the OBO V20C surge protector. The contact on the inside normally opens the circuit if the leakage current is to high and so it is not designed for high currents. Normally the maximum fuse is a 125A type. The pin on the back side is for an auxiliary switch to signalise a damaged or missing unit.

[@Uncle-Duncan-Shack]

Hi Clive, Greetings from Uncle Duncan in South Africa. The Dehnguard which costs over a hundred pounds is the good one. We use them. The MOV is a lot bigger, like the size of the biggest cookie you could fit in there and it's not potted. Also we space them apart on the rail as we have learnt that the energy of course becomes warmth. They do knock out a micro switchy type device in the base of the ones we use and then the machinery we installed it into goes quiet, with a message of bad news on the pc screen. The waveform of the mains which in Zambia resembles AM modulation tends to cause quite a bit of this. Thanks for a great video, D

[@Pidroe]

It's not supposed to break the circuit, It's only supposed to trip the breaker by making direct contact with erath. Once it does that the surge protector is broken and can not be used anymore. It shows this in the window on top and via the a contact on the bottom (if the bottom part is equipped with that) So the solder part is only used to show that the surge protector is tripped and needs to be replaced. Flip up the breaker before it again and the circuit is live but unprotected

[@jackwhite3820]

But it's not making direct contact with earth and it's not guaranteed to trip the breaker.

[@picsi-software]

yes it is, the MOV is between Line and earth.. when it goes over voltage it will connect to earth which is supposed to trigger either the RLC or the breaker... generally if it is a serious surge it over heats, trips the flag and wrecks the socket

[@schwarzarne]

mguruguru it will either melt the solder or trip the rlc, it won't do both. because after one did go open circuit there is no more current to trip the other.

[@jackwhite3820]

Alright I looked more closely, it's actually a type D surge protector, so it's supposed to be installed after a RLC. Then yes, it would trip the RLC. But TOMZN also makes type C surge protectors and I bet they have the same shitty construction and then you don't have a RLC to save your ass, because MOV's are not guaranteed to fail dead short. They may fail open circuit or somewhere in between and if it's below the trip current of the breaker then this thing could start a small fire.

[@martinlang9615]

Pidroe I agree, by tripping the Main Switch circuit breaker, it has performed its function. Even if the Solder is still connected, it will not be a safety hazard (even if is live to the turned off main switch, as an electrician is trained to test and know what to do in this circumstance), that being to remove the surge arrestor replaceable module. If the solder were to still to connect between active and earth, it would be vapourised by the direct short to earth, hence leave a big enough safe gap.

[@Markus0021]

Proud to say I possess the special engineering skill of stabbing myself with a screwdriver while prying on things. I've utilized the skill multiple times in the past, in fact. ;-)

[@Ed19601]

Mark L you are not a real engineer until you have seen blood on yr tools.

[@DogsBAwesome]

I put a screwdriver right through my palm and it came out the back of the hand without any other damage apart from the hole. I was considerably lucky.

[@kay110]

Yep - Been there and done that myself. Actually not much bleeding either which was strange...

[@petermoore4056]

Is the problem with not breaking the connection because the unit is upside down and the metal plate would if installed upright drop under gravity because of the slot in the middle. Still, the flag system seems flawed anyway.

[@lorenhusky2717]

I tried to pry a beer cap off with a flat blade screw driver and it went horribly wrong and I stabbed myself in the forehead. Lucky I didn't lose an eye - seriously. I'll never do that again.

[@markn2904]

Have you considered the impact of gravity to the melting of the solder? Both times you melted the circuit it was flat on its side. If the component was in place the heat would be coming up the long arm of the switch and melting down that arm.

[@Zlodej5]

Not all DBs or din rails mount parts/switches standing (eg 3 phase style boards...), utilizing gravity as a part of safety system is a bad idea for many reasons... Unless orienttion is specified on spd I would actually pass it even if fitted upside down

[@jusb1066]

you stop seeing the green when the orange flames of the house fire cover it, thats your safety

[@matthewspencer5086]

The safety device may use model-maker's solder rather than electronics multicore. Because when you solder a new bit onto a model, the bits you did before can desolder themselves and fall off, modellers have at least a dozen (sometimes more) different solders with different melting points. and you start off in the middle of the model, using the highest melting point solder, and as you work outwards, you use lower and lower MP solders (and turn the soldering iron down as you go!) In the seventies, some model-shops, specialising in cast metal models, would have a shelf with about fifty different grades of solder on it. This is why plastic Airfix models won out in the end. Some hard-core people will still build model steam engines and the like from dozens of die-cast bits, tacked together with a pallete of different solders. It would be possible to select exactly the right melting point, if the maker was bothered...

[@ricknelson947]

Clive, thanks for discombobulating one of these for me. I checked the specs on this model. It is important to remember that for sensitive electronics to be protected from lightening surges. You need a response time of

[@throttlebottle5906]

the failure on protectors like that usually isn't full short, but rather modest current leakage, so the solder would heat slowly until it couldn't hold the spring tension anymore and pop out suddenly. they are probably meant to be right side up also

[@BojeBager]

In Denmark we have the lightning protection connected in a 3 + 1 connection. From each of the 3 phases we have a 275V varistor too neutral. Between neutral and earth we have a 255V spark gab. We are no longer using the connection with four varistors from each of the 3 phases and neutral to earth because when the varistor between neutral and earth have a leak current will the RCD perhaps not trig!

[@mnx4me]

Great Videos Clive. I have these fitted. I`m not expert!. But they have to be used in conjunction with the MCB/RCD combo, (or any fuse). That is what isolates the circuit not the Surge Protector. I think the part your were desoldering is just the flag to tell you the unit has failed. They fail eventually if you have multiple surges (they say) So as I understand it, the unit goes low resistance very quickly after the voltage exceeds a preset value. that low resistance draws enough current to trip the consumer unit fuse. Job done. The flag may still be green telling you the unit is still viable. Hopefully they work as designed!!...We live in the mountains and the mains gets hit often.. Thanks again.

[@NeilWhelchel]

I thought that I would point out that if the voltage is high enough to drive the MOV into conduction long enough to heat to melt the solder, it is likely high enough to arc even if the solder falls away from the gap. It needs to have some sort of flame suppression, (sand or similar like a fuse), and a much wider gap. I am guessing that the resulting arc would fill the box with metal vapor and plasma in a way that would get across to the other side and go into complete runaway. I would really like to see how spectacular the fireworks are when this happens!

[@goata007]

i think breaker would trip, extinguishing the arc

[@JasperJanssen]

In actual use these are behind a fairly hefty (dedicated) circuit breaker. They don’t have to break tHe circuit, unless it gets really hot without tripping the 40A or so breaker.

[@TizianoBacocco]

I've bought some of these and did the same test, they opened correctly with approx 2mm gap, what've noticed is that the solder they used kinda breaks at some temperature instead of melting and creating bridges like yours, and the clearance is a bit higher

[@Neffers_UK]

Photonic should "test" one of these...

[@mastergx1]

I know this video is about 5 years old now but just a quick heads up when it comes to potted resin - excess heat will usually cause it to break its bonds and start crumbling. In my old job we sometimes had to remove resin from test-failed parts and I discovered by accident that a fair amount of heat (about 300c) is enough, well within range of professional heat guns. The trick is to do it in stages, heat a bit up and break it off, rince and repeat until you liberate the parts from the resin. Side note: All SPDs that I've fitted so far require overcurrent protection. Most call for a 32a MCB or RCBO so If one did ever fail short circuit - ADS would occur due to the short. Upon seeing red in the window it would not take long to realise what has failed.

[@tazz1669]

love the auto repair function comment, how true, another great Clive video

[@ethanpoole3443]

tazz1669 It's amazing, though, how painful anything under a fingernail is, and especially when the nail gets lifted as well! Thankfully we do heal because I seem to inflict that injury upon myself much too regularly!

[@wildysnow547]

My hands are nearly worn out, love the end cut pliers not as many pointy bits to get in the way and the end cut pliers/pincers have better leverage. The end cut also double up as little knockometer at times as well, the right tool for the job so to speak.

[@jjab99]

I am not 100% sure, but if the current was so high that it caused the solder to melt in the first place, that same current would most likely vaporise any strings of solder left behind. But as I would not like to bet my life on it, I will agree that the design could be a little better. I don't think it would take too much of a change to make it a lot better. A shorter, stronger spring, less solder and trimming the excess plastic that was fouling as the spring pulled the contacts apart would do the job.

[@bigclivedotcom]

The failure mode of MOVs is to reduce in resistance so that the standard mains voltage is enough to pass current at a level high enough to cause heating, but not enough to trip an overcurrent device or melt the solder directly.

[@Subgunman]

That rear plunger is used for mounts that have a secondary micro switch so when they trip they open or close the switch and trip a remote alarm. I use Hager brand products where there is an optional switch equipped base for the alarm feature.

[@restcure]

Judging by the print direction, it looks as if the spring DOES have a gravity assist, maybe giving a li'l bit more gap, not being held upside down. As a bit of a change from other vids I've seen, where your hands just appear on screen pre-injured, I finally get to see the actual injuring process!

[@SigEpBlue]

Must be an auspicious time for finger injuries, Clive. I had to visit the ER yesterday to have the tip of my left index finger superglued back on, after running a serrated knife through it .

[@mistermatix8241]

big clive digging into that potted varistor, its like an electronics version of one of those "dig the plastic dinosaur fossil from the chalky block using weak plastic tools" toys you see in poundland!

[@electronicsoldandnew]

I would really like to see the video of you putting this thing back together again. Great videos. Thank you.

[@luked9301]

love your videos. I think the soldered tab may be designed to only allow the green plastic to move down and disconnect the circuit from the back tab.

[@brutlern]

Videos are always a lot more interesting when sir brute force joins in on the activities.

[@Christian_Banks]

Its so nice being able to watch you do this so I don't have to. Saves me from the pain and the cleanup of giving in to curiosity. xD

[@xxwookey]

I've just got a YUEXIN SPD which looks extremely similar, except that it's not yellow. The innards are very similar but not quite the same. Rather than one tab being soldered into another, in mine the tab is soldered to a bit of stiff wire coming from the varistor. Maybe slightly more travel, but a similar risk of still touching/having a solder bridge. They are supposed to be fitted with a 20 or 32A MCB so if the things fails short-circuit that should trip, or melt the rest of the solder before anything catches fire, but who knows. You can buy these SPDs online for a fiver now, which is crazy - I do wonder if there is anything inside those. This one was 12 quid. Brands you've actually heard of start about 20 quid. Fancy ones are 50-70, but those probably have the electronic detector in as well, not just a MOV. Thanks for taking one to bits so I didn't have to destroy mine

[@sciencetestsubject]

my fuse box has a similar looking device on across the input. however it has 2 different modules identified V and T. V type is across the line and neutral, and the T type is across the neutral and protective earth.

[@DoRC]

yeah im thinking it was designed originally with a shorter spring.

[@Spiralem]

i think by placing the window lower and having the metal strip shorter, it would move a greater distance when it fused

[@dagbruck]

"Uninspiring safety device" is a seductive teaser second to none.

[@EffendiChung]

This is the best thing about a senior engineer or mechanic traits. When they're wounded in a job, they'll just tend the wound a bit, and keep working. A bloody finger? Just wrap a tissue paper with electrical tape and continue.

[@rimmersbryggeri]

Senior I accidently mashed my finger on a feeding wheel on a big table saw once. (Someone had turned it on when it wasnt supposed to be engaged". I did just that put a plaster and some paper tissue and masking tape on it and kept on working.

[@tin2001]

Effendi Chung I do the sticky tape and paper towel/tissue/toilet paper thing all the time. Easier than finding a real Band-Aid™

[@EffendiChung]

B.L. Alley Our engineers does. But they will use anything they could find within an arms reach. Thats why I always made sure to keep some first aid kits ready. My mechanic even use fresh chassis grease to stop bleeding. 😣

[@petti78]

CA glue works like a charm. That's why the bottle always states "Glues skin and eyes immediately" or somesuch. It's an instruction, not a warning ;)

[@xAtNight]

mharris1270 while you are right about the glue and hospital stuff, I would NEVER recommend to put glue into your eyes. Never do it unless advised to by a professional doctor.

[@stefanejegod8644]

BigClive, the scientific way of taking things apart. Nice to know about that auto-repair function though!

[@casemodder89]

try out the red ones named Dehn guard. german top notch brand in surge and lightningstrike protection. should be serval steps up in quality and sophisticated.

[@casimirkonrad9590]

The green lever activates a signalling contact in the socket of the SPD. Well, YOUR socket does not have this contact, they produce two versions. The signalling contact is needed if you want e.g. an external warning light if the SPD is defective.

[@Technossomy]

You should of given one to john ward to try out as he's got a variac voltage regulator. Would of been nice to see how safe it really is

[@Aubreykun]

My comment probably won't be seen but: Clive have you considered getting a small clamp-on bench vise for brute force sheninigans? If anything just to keep the main bits from flying everywhere. Plus the opportunity for double the force on the snips. Might also be a good idea to get a small chisel and hammer to break into resin or other extremely stubborn bits.

[@DualityElite]

Buying stuff and destroying it. ...I like this guy

[@ownpj]

When can we buy official BigClive spudgers?

[@wheeltapper1]

I got one here www.ebay.co.uk/itm/iSesamo-genuine-spudger-repair-opening-pry-tool-for-Apple-iPod-iPhone-and-iPad-/281472320040

[@17hmr243]

put me down for few too till then fea-bay phone screen repair kit - is where u find them

[@kirkb4989]

It needs the BigClive face logo on it. Then think of all the spudging you could do with it. Or is that more spooging?!?? Hmmm...

[@SianaGearz]

kirkb4989 I'll take one with a genetic sample of the beard.

[@OAleathaO]

For those looking for these in the States, you can find them on Amazon and the USA eBay. Just do a search for iSesamo. The company that makes them, however, hasn't started offering a version with BigClive's logo on it unfortunately... ~sigh~

[@nickandpammorano9346]

keep in mind that a dead short would cause it to trip in the off position. if the device did not completely trip in the off position, the dead short will still be there. so the triping condition will cause the device to trip again very fast! The complete open circuit will be completed in less of a second.

[@resanila]

It seems that you're holding/tripping it upside down, it could be that part of it's mechanism is relying on gravity to pull the metal arm further away and down from the connection.

[@jafafa]

The metal piece seems to be loose on the green plastic, and the hole through the metal piece which the green tab slots into is longer... when you heated the solder, you were holding these upside down from the position they would be mounted in. Is it possible that if the solder melts with them held proper-side up, that the extra play that the hole in the metal slot allows would let that metal connector to be pulled down by gravity, making the gap wider and making a solder bridge less likely to form?

[@jaccohuisman]

I had almost bought a similar surge protector. for 3 phase current It was offered under the name of a local importer but turned out to be from a manufacturer on Alibaba). I don't want to take risks with safety equipment so I decided buy a real brand (OBO Bettermann V10). I have opened it up ;-) It is built considerably better than the one in this video. It has 3 square varistors and a fourth disc-shaped component which is probably the varistor between N and earth.

[@BonannoCM]

As someone with a horrible record of putting things I've taken apart back together, I've always enjoyed this channel. I am, however, beginning to suspect Clive's work is sponsored by a band-aid manufacturer. ;)

[@millomweb]

Stabbing oneself with a screwdriver - special engineering skill - reminds me of the time.... Working on car brakes - with small high power springs - I once slipped and managed to catch my watch strap on the _assembly_ with such force that it peeled the strap end from around the pin that holds it on to the watch. Simple matter of reassembly of the strap round the pin and tapping it back over with a hammer. Shame really it was quite a good watch. Haven't worn a watch since.

[@exaisle]

Hi Clive......you had the SPD orientated horizontally when you melted the solder to make it "trip". I'm wondering if the separation would have been more if it had been orientated vertically, as it would be when fitted in a consumer unit?

[@bigclivedotcom]

I may have another go.

[@exaisle]

@@bigclivedotcom I've been having suspected transient spikes with various devices and machines blowing up/breaking down over the past few years...waiting for the electricity supplier to get back to me on the result of a monitor that they put on my supply. In the meantime i've bought a couple of SPD's which I'll stick in (install one, keep the other two inserts for spares) and see if that solves the problem. Well worth it for about £8 each..

[@EpicLPer]

Bloody thumb? Pff, let's finish this video anyways! That's why I like Clive :'D

[@ArlenMoulton2]

agree

[@mistermatix8241]

EpicLPer Clive is a legend! takes a lickin', keeps on tickin'! prefer Clive to that aussie snob, Dave Jones from EEVBLOG

Professionalism there. ;)

[@rimmersbryggeri]

Me to they have totally different channels though. Dave is agood teacher but would be a little easier learning from if his voice wasnt like a housewife from Neighbours.

[@SteelSkin667]

I've had that exact injury a couple of times, it's really unpleasant. Once it happened I was peeling a clementine using my thumbnail. That's when you realise that clementine juice is more acidic than it seems.

[@edwinwaugh]

The markings on the thermal cut out ( L, N ) suggest that its used in a single circuit. BUT and its a big but, both live and neutral are meant to be linked making it a double pole isolator. If the solder was to heat and break the contact on the NEUTRAL side it will stop the appliance from working BUT its now in a dangerous state as there will be 240v present at the appliance relative to earth. PS Great show !

[@bigclivedotcom]

It's just hooked across the mains. It's not in line with a circuit.

[@roccovalotta9490]

Looking at it... I wonder if if needs to be in vertical orientation so that is it lets go it pulls the solder away from the contact?

[@robertbullock4266]

hey bubby a full sheet of course sand paper will work to with less injury, can see in t to caps and other stuff.

[@korishan]

For the solder joint, I'd say that when it actually begins to fail, the arc created as the join separates will probably finish off the remainder of the solder created a wider gap between the two contacts. That's my guess, anyways. I learned that about some glass fuses as this is the way they work.

[@ethanpoole3443]

Bobby Hicks Except that there is no arc so long as the conductive bridge remains (the arc only follows once the bridge between both sides goes open and you get back EMF from an inductive kick). That said, the lower contact should still remain a liquified puddle of solder so long as current flows through the MOV, so it may still separate eventually after things warm up a bit more.

[@SueBobChicVid]

Could the spring be attached to the stanchion to the right of the one it is attached to? It may interfere with the green armature, but it would provide a lot more tension and move the contact further when it opens.

[@rtesimpson]

Was thinking the same...

[@sjokomelk]

You are not happy with it not breaking the circuit properly, but there is no current going there. It's only shorting out to ground/earth when there is a voltage spike. So there is no need to have a huge gap for disconnecting the circuit. It is only there to tell the user that the MOV has been "used up" and needs replacing.

[@Monkeh616]

And when the MOV fails, the MOV gets very, very, very hot and tries to catch fire. This is why the proper ones have thermal fuses.

[@6F6G]

Reminds me of fusible-repairable resistors used in some old TV sets.

It will arc and splatter the fuse alloy. And it is meant to trip your fuse in a surge. So it is to be mounted as close to the inside part of the panel, after your main breakers and diferential protection. I have to get me some of those... :D

[@olakarasupport3905]

summary: This device will trip the ELCB and the power will be disconnected. Also MOV inside is protected against fire with the porcelain covering. But the indication mechanism may or may not work :)

[@clems6989]

I have actually done this same thing with a Schneider device. And the green thing is an indicator that it has activated and you must replace it.

[@dhruvchawla5476]

You should make merch with a photo of the table burn marks on it!

[@6F6G]

In normal operation the solder joint temperature rise would be very slow. Under these conditions just below the melting point the solder would soften and break before it became fully molten causing a clean break without leaving a solder bridge.

[@THEDRAGONBOOSTER8]

I would like to see a couple more of these tested again ,in different ways..Please..

[@SueBobChicVid]

I love this stuff! Watching him tear into things... priceless.

[@centerrightproudamerican5727]

I agree that the thermal break does not seem very robust. However, In a real event, a few factors could come into play: 1) By the time the solder bridge pops in a 'real' event, *everything* is pretty hot. The solder could remain liquid longer and the solder flow away. (In the soldering iron test, the heat is immediately removed) 2) If a solder bridge is formed the current will continue to flow, generating heat and causing the solder to flow away - OR - 3) The rapid heating of the soldering iron may not be representative of what happens. Could it be that the solder bridge breaks when the solder is soft but not fully liquified? To properly test the device would require actually over-voltaging it.

[@houseofsteinert]

Hey Clive, according to Wikipedia ( en.wikipedia.org/wiki/Surge_protector ) the green plastic shows failure (life to protective ground connection). The MOV closes connection to protective ground in case of overcurrent trough lightning strikes. That's why the connectors of your device are labeled Life, Neutral and protective ground.

[@BenjaminEsposti]

I wonder if it will catch on fire like those Supco surge protectors they put on air conditioning units. They're well known for catching on fire (hundreds have caught fire), and Supco knows about the problem, however they haven't recalled them.

[@sangeeth_619]

Can you make a tutorial about MOV and other safety components? That'd be awesome!

[@wildness01]

This isn't a circuit breaker. It directs a surge to ground and shorts l&n together the only thing the flag does is notify you that it has been activated. They are commonly used in solar combine boxes to suppress lightning strikes

[@ChaplainDaveSparks]

Just out of curiosity ... Might a Dremel tool work better for cutting away the potting material?

[@gproto1]

in this case you do not want to break the circuit, because if the circuit is broken you would be able to switch back on the circuit breaker and maybe not replace the faulty varistor! is safer for the circuit and people to keep it short circuited when it actuates, enforcing replacement for a new one. spetially on the ones that do not have an auxiliary contact for monitoring is state!

[@repairitdontreplaceit]

clive , can i suggest you try lots of current through it and mount it in the correct orientation with the side panel of so we can see what happens when it trips out

[@SKraus-pb1ii]

Not sure what the reason of breaking the circuit here should be. It is just the connection between L and PE or N and PE that would trip?

[@AlphasysNl]

Not really sure if your test results are accuracte with this one, Clive. Gravity might have helped the failure of these devices along in a normal operational setting, eliminating the solder bridge.

[@davidb5255]

Hi Clive I wonder if the solder joint would have failed better if you had played a heat gun on the joint and surrounding area, after all in the event of a failure the whole of the inside of the unit would have heard up given the enclosed space. This have maybe made the solder more liquid due to the generally high ambient temperature and so may have parted more cleanly. Just a thought. Great bit of destruction anyway. David

[@warialinth]

Yup you might got ones with wrong spring. Also when these go dead short, they go with quite bang and oftenly explosively unplug/disassemble themselves from the socket. ;)

[@thomas316]

Wouldn't be a propper Big Clive video without a hand injury prior to or during filming. So...will there be a destructive test? I'm quite interested in what would happen in a real world application.

[@peterdkay]

Soldering should only be on "back" side so when MOV overheats, solder lets go and is not drawn through hole. That way you would get a few mm of clearance to break the arc. Would love to see you put 400VAC on this to see it explode!

[@danielhoolihan]

love your work.. but umm.. @10m55s - upside down miss jane.. they don't fail upwards.. they fail falling down.. so hold it the correct way up and the hole in the metal arm will hang a few mm further down and/or will pivot??!? that may give you the "3 or 4 mm" mentioned @12m15s

[@Exagear]

send it 2 photonicinduction

[@jimsmindonline]

Definitely needs further testing, Photonicinducton would give it a fair go!

[@tysondundas1947]

Are they replying on the fact the contact arm should fall away as you where holding the SPD unpside down when desoldering ?

[@opshacom1]

Bigclive.Can you draw a wiring diagram and explain how it works?I got another concern with it about the protection.

[@c.james.cornwalll3060]

The 'PLIERS OF PAIN' strike again 🤕 And you get a bonus chunky piece of solder wick inside the breaker..throw the rest in the bin..

[@gproto1]

correct assumption bigclivedotcom! at least we use them that way!

[@jackwhite3820]

The more expensive ones I've seen don't have an indicator window on the neutral side, because it's actually misleading to have one there. On the neutral side the indicator would not change state when the MOV goes bad.

[@grapsorz]

that solder thing must have something to do with the smal tapp and the housing.. whats inside that? you forgot to look inside the mounting thinge.

[@wildysnow547]

Would be interesting to see what voltage/spike would let the pixies out.

[@timlong7289]

I did notice you were holding it upside down and there seemed to be a bit of 'wiggle room' in the linkage. Maybe it would benefit from Gravity Assist in a real failure mode - but yeah not very confidence inspiring at all.

[@BarsMonster]

Even if gap would be wider - it would be far from regular circuit breakers. There is no arc extinguishing chamber. I believe that would not be able to cut even 500A with WIDER gap. I assume this device is not expected to cut short-cicruit currents and regular circuit-breaker is expected to be connected in series.

[@bigclivedotcom]

It's only expected to break its own fault current which would only be the amount that was causing it to heat. Probably around 50mA.