I also loved the demonstration of the SPD's function upon it's exposure to increasingly higher voltage and it's dramatically decreasing Resistance. Thank you again

Absolutely Amazing! thank you John for sharing the knowledge. I appreciate your time making these great videos.

Thank you John for this tutorial. Keep up the good work!

Both parts are highly educative and practically useful! Thanks!

Great video and as usual excellent demonstration. Keep on 👍

Very informative and great explanation sir.....firstly telling theory and then proving that theory with practical...just awesome...I will give presentation in my class over this topic

Nice demonstration of the MOV operation!

JW, Thank you very much for this series of videos, I've never seen MOV's explained so thoroughly before.

As always, your videos are very informative, thank you John Ward for your great job.

Very informative, I understand that the multimeter has MOVs in as well.

John...... we just want to see you. Blow it up! Never did thankyou for getting me through two of my exams. Honestly couldn't have done it without your videos, thankyou so much

@gassanali8667

4 жыл бұрын

What are those videos?

Thanks for another great video JW

Thank you for a brilliant video, great teaching skills.

for information in dutch systems the SPD (OSB) needs to be in a location withing 40CM of the incoming (main) ground (PE). also a type 2 only need a fuse if it can pull more than 125A if it breaks, if do u use a 63A fuse. a type1 can take 250A and need a 125A fuse if the installation can handle more than 250A and last but not least a type 1+2 needs to follow the type 2 specs.

Great stuff as always!

Amazing demonstaration John. Now I can understand how that small stuff working........very easy to understand....

Very good thanks always wondered how they work.

Very useful intro and inside details. It helped a lot understanding how this device works.

This video was extremely helpful. Trying to protect some expensive equipment I have ere, I got the lucky the other day when lighting hit. No more risks (or much, much less risk) this time around Thanks!

Thanks for that. Not just theory but and in practice. Valuable info

Very nice video. Very very useful. First time I know how to check MOV at home. 👍

Thanks for the detailed information!

Thanks !!!! Your demonstration is great!!!! Congratulations for your great work :)

Great demo of the surge protector working. First time seen someone do that. 👍

Thank you John Brilliant from John.

Top stuff, JW, thank you.

Very good and vital lesson. Thank you

Thanks for the explanations. If I understand you correctly, the SPD is only side-wired to the main power flow of the individual conductors (which would explain why for each conductor there is just one connection coming in, but not coming out again, apart from short-circuiting to one of the other conductors, in case of a voltage surge). This also means that the main lines are not interrupted, so if e.g. a lightning strike feed its energy into a phase or neutral conductor of the main power line, what prevents the current from reaching connected devices? Is it only about the path of least resistance?

Great demo !

wow. best explanation video I ever watched. keep up the good work.

Wonderful explanation. Thank you.

Super work

As per your demonstration each surge protective module seems to have a clamping voltage limit of about 600 V DC. So when installed, as both devices are in series with the Live and Neutral lines, wound't it give a surge protection above 1200V (or 850 V AC) or so between the lines? isn't it to high?

excellent. well done! very helpful

Great explanation John. I was trying to understand the failure modes after we some kind of significant surge resulting in a neighborhood power outage for 24hours (I assume the power company swapped a transformer). I had a power strip surge protector with two MOV devices [L, N]. When the surge occurred, it tripped the breaker. Upon resetting the breaker, the surge protector burned, indicating a direct short. I didn't know the MOV would fail shorted but it did it's job. We had 3 circuits trip, all of which had MOV surge protectors. Two of which failed permanently (or rather, "succeeded" by dying :-). As a result, I'm looking at how best to protect the electric panel at the source. Is there any type of surge protector/breaker that can reset automatically after a single event upset?

Just Amazing sir...Salute to you

Great through analysis!!!

I have at home a TT installation, and 3 x 230 Vac plus neutral. A bit more troublesome to install SPDs. The video didn't explain the differences between (Type 1,) Type 2, Type 3 SPDs. Also, some SPDs only contain MOVs, but many also GDTs (and TVS diodes).

Highly informative lecture. Surge protector demystified

Beautifully investigated.

Wonderful, not seen any explanation like this.

Brilliant explanation and demo. Haven’t seen a Mega like that since about 1980 when I was an apprentice. The electricians would love to give the apprentice a shock with the handle spinning and max rpm. 😂.

@Rob-ln7dd

Жыл бұрын

Yep got zapped myself in 1980... I went to the factory for a 2 week induction after finishing O levels before starting first year training at the local tech college in September. As i was one of the youngest in my year I was only 15 years old for the first week...loved it... Apart from the megger zap. It was a boiler and radiator manufacturer in Yorkshire, the electrical workshop was a dark place (ironically) and Dick the oldest sparky held challenges to see who could hold the Megger for the longest time and get the highest reading.... He could of course... ElfNSafety didn't exist...hahaha

hi how r u I have a question if the SPD is shorted and damaged (shorted for ever ) then the previous C.B should be trip am right? what about coordination between devices

Very informative...Thanks

I don't like how much that tab pokes through the solder joint, will it actually separate or just left arcing is anyone's guess but I would like to see a shorter tab poke through.

excellent !

If they fail open circuit, that could happen during a thunder storm? First few strikes are handled, then the module opens up? Are there versions that fail short circuit instead? I would rather have to investigate why the fuses blow than replacing all electronics in the house.

Great explanation of SPD’s and their role 👍🏼

'Novel Idea' of installing a Single SPD across the 'Neutal' and 'Live/Phase' wires when one has no provision of an effective 'Ground/ Earth'. Excellent idea. I liked it.

Great stuff JW! What size over current protection would you recommend for a 63A residential house?

GREAT DEMO !

Thanks you Great video

could the plastic melt 1st and pull down leaving the solder to keep heating It will still show red but if no one looks each day who will know

This was really helpful mate. Thank you.

So for my solar system having an open circuit Voltage (Voc) of 38Volts. What should be the size or rating of DC SPD?

Well done

7:24 You have shown SPD connected between line and neutral whereas it should be really between line and earth or between neutral and earth right? Also there cant be a scenario of the surge passing from line to neutral as in 4:03 as the common point of the two modules are connected to earth which should bypass the surge from either line or neutral right, unless earth wire is broken of course?

Very informative

Thank good information

At 8:24 when voltage go up, the mov resistance fall, which basically mean L & N will have connection to each other.. wouldn't it blow? Because when L & N is connected it produce very high current

Anyone knows of this could help with induction cookers displaying error codes related with voltages?

It would be nice to see the MOV that's hiding in the resin. Being a cheap unit I wonder if it really is a good sized MOV or just a well hidden tiny one.

@troytaylor1913

2 жыл бұрын

I found that I can buy these Chinese MOV's about ten cents per part no matter what the value or size. If a factory buys reels in volume the price goes down even lower. Where I worked they bought components like these for 2 cents. It makes me wonder why a multimeter with a MOV costs three times as much as a multimeter without.

When those MOV's go they really go up in smoke if they are unfused. I use to work in a packing factory and about once every three months a MOV in one of the bagging machines would burn up and stink up the whole factory. My boss was dumb and couldn't understand why I wanted to replace components that would burn up on occasion. For me replacing them was very important because the circuit boards the MOV's protected in those machines cost thousands.

Bloody legend! 👍 Great breakdown

I had a surge protector installed in my consumer unit, but the inserts are 2 different types. The insert between line and earth has a model number with a V inside it, but the insert between neutral and earth has a T in its model number. It's also labelled N/PE on the case.

@muzikman2008

4 жыл бұрын

Ones a MOV Varistor, and the other is a gas discharge tube..I think..

nice demonstration, i always wanted an insulation tester but never managed to buy one yet

excellent demonstration!

I seen plenty of MOVs blow up and cause fire and serious damage to the wiring, at least these ones are encased in resin. Earth leakage also trips during lightening storms which protected me over the years, now they are making surge protection mandatory. Most sensitive appliances already have surge protection built in.

So to put that inbetween solar panels and inverter your supposed to run the L and N in and run another set in the same hole coming out to carry on , really makes no sense , id like to see you wire one into a system instead of drawing lines and disecting the device . or does this just run off the side of the breaker and is supposed to just capture said surge?

Im concearned that when mov wears out (with many less severe spikes), it wouldnt always show red as solder would have to melt first. Also when mov has worn out does it give us an open circuit?

@jwflame

2 жыл бұрын

When they fail, they become more conductive, until eventually enough current flows to heat up the solder link and cause it to melt. It's a chemical compound, there isn't any realistic way it could fail open circuit.

John, write this down in your diary. 1st March 9pm on River Gibbs FM (easily heard via internet). You get a mention after first track and appear in the intro! - Hello, I'm JW....

@EFIELDIQ

4 жыл бұрын

Hi Jackbox how are you

According to manufacturer Dehn, the only SPD suited for use in a TT earthing system has a MOV from L to N and then from N to Pe; no direct path from L to Pe. What could be the reason for this?

@sdgelectronics

4 жыл бұрын

To avoid the risk of a failing MOV causing the CPC to rise up to dangerous potentials.

Why Chinese SPDs are mostly 385V but those sold in Europe usually 275V. Is there actually difference?

thanks for the explanation, i thought when there's a higher voltage it will discharge it via the earth part

Was it BigClive or David Savery that did a video on this about a year ago? He simulated a thermal event using a soldering iron to allow the spring mechanism to operate. The solder melted and pulled the conducting link downwards, but the excessive length of the link meant that a gap didn't successfully form. It looks to me that this is likely to happen on these Xufeng devices. Any chance we could see this demonstrated on the one that didn't get mangled?

@jwflame

4 жыл бұрын

Yes. Have got 4 of these orange cartridges, so 3 intact ones to do something with.

@muzikman2008

4 жыл бұрын

Yeah was Big Clive, another money making scam this crap....

@aptsys

4 жыл бұрын

It was SDG Electronics that used the soldering iron to simulate an overheat event.

A wylex SPD in a domestic consumer unit is rated at 125amps so the SPD is protected by fire by the 100 amp cutout fuse.The cable to the unit could be 2.5mm so I would connect via a 16amp breaker not 32amp as suggested by this gentleman .I am always open to further insight into these resently new devices.

@angelanuccio2167

8 ай бұрын

I loved your input , could you tell me how i can run L and N into one hole and then L and N carry on , am i supposed to run 2 wires into each hole like hes been drawing ?

@bernardcharlesworth9860

8 ай бұрын

@@angelanuccio2167 no it's just a three wire device .line from breaker.neutral from buss bar and earth to earth bar. On overvoltage it dumps power to earth.

Hi John, what would be your thoughts on SPD’s if I was the ONLY one to fit an SPD in my street. My thoughts is that a LOCAL Surge would head to my Consumer board first up and cause major damage . Brian W

@jwflame

4 жыл бұрын

If you are the only one, then you have protection and everyone else does not. It won't damage anything, surges do not seek out SPDs. In an extreme case your SPD might be damaged, but everyone else would have other equipment damaged which will cost far more than replacing an SPD.

Will you be covering the surge protection that is apparently present in many extension leads? It is my understanding that, as long as RCDs and these MOV devices are present in the consumer unit, such "surge protection" as in extension leads is useless.

@jwflame

4 жыл бұрын

Depends on the distance from the consumer unit to the outlets - it may still be required for distances over 10 metres away from the consumer unit device.

@Mark1024MAK

4 жыл бұрын

Jivan Pal - the manufacturers will have you believe that there is no such thing as too much surge protection... But then again, the consumer unit versions are considerably more expensive than having a reasonable number of surge protected extension leads... The choice is yours. RCDs don’t really affect things, other than they are useful in switching off the supply if a surge protected extension lead suffers a failure of the protection system and leakage current flows to earth from either the line or neutral circuits.

Are AC and DC compatible? Same MOV components? Thanks

That was both interesting and educational. After the cartridge shorts during a power surge... Does it continue to rush the power to earth (Literally running up the meter)? Or does it cut off the power as well? When a high flow of voltage comes through and causes the compound to be conductive, does it revert to it's original state later on?

@jwflame

Жыл бұрын

It's effectively a short circuit for the duration of the surge, and returns to a very high resistance afterwards. However that duration is typically measured in microseconds so the energy dissipated is far too small to make any difference to meter readings.

@rossi6329

Жыл бұрын

@@jwflame Aren't these one time/ replaceable cartridges? Or as you said it returns to being non conductive after it Earth's a surge. So continues to do is job again even when the indicator is red?

How do we get a N/E transient if N and E are bonded at the service entrance panel? How would an over current device between L and N protect against a N/E “short?” Many more questions on the N/E issue. This whole area is confusing because of the N/E bond.

@jwflame

4 жыл бұрын

TT and TN-S supplies don't have that link at the panel.

The unit tested. A normal consumer unit has usually 16mm or 25mm meter supply tails into the box. What size cable should be used on the surge protection device on a normal domestic CU?

@jwflame

4 жыл бұрын

6mm² minimum in most cases.

@johnburns4017

4 жыл бұрын

@@jwflame Thanks. I suppose the 6mm off the incomer switch with the earth and neutral off the bus bars. Would be nice if the unit could be off the L bus bar.

do you put the surge protection before or after the breaker?

@bernardcharlesworth9860

2 жыл бұрын

After as the SPD is looking at transients.In such a short time the current is relatively low and the breaker does not trip but will if there's a wiring fault between the breaker and spd

What happened to your Megger? The crank unit is amusing, but I wouldn't trust it as much. It would be quite interesting to use a temperature controlled soldering iron to melt that tab and see what the actual temperature required is.

@jwflame

4 жыл бұрын

Nothing happened to it, just wasn't used in this particular video.

Excellent presentation as always. Does it mean then that if the MOV goes open circuit and the solder link remains intact there is no way of knowing if the device has failed? Interesting to note that it has a linear response to increasing voltage. Thank you John.

@jwflame

3 жыл бұрын

If it did go open circuit, then there would be no obvious way to know. However MOVs don't work like that - it's a solid compressed block of material, as they degrade, they become more conductive, until they conduct all the time, which is when the solder melts due to excess current causing it to heat up.

@dave-d

3 жыл бұрын

@@jwflame Thank you John.

@robertnyamavuvu5875

2 жыл бұрын

@@jwflame hi does it mean this spd can operate without breaking turning red on the display and remain in use

am i right in thinking that this device should defintely not have an rcbo protecting it just a regular mcb for over current?

@benbaselet2026

4 жыл бұрын

I can't think of any good reason why RC protection would not be in order, in addition to the self evident over current protection?

@MultiPureEnergy

4 жыл бұрын

Pentti Kantanen these devices leak small amounts of current to ground, more so as they age, which could cause nuisance trips of an rcbo. That is why good ones have thermal protection for the MOV, to detect when it’s getting too toasty from the leaking current.

@Mark1024MAK

4 жыл бұрын

Jacob Wells - when new and undamaged, they should not leak any significant current. Once damaged, all bets are off.

Perhaps device failure would first cause the plastic to soften before the solder would melt? There seems to be no internal fuse, so could this start a fire if it fails and overheats just to the point that the plastic melts but not the solder? Perhaps it'll have thermal runaway and melt the solder anyway, so this wouldn't be a concern? This unit is tiny compared to the Eaton CHSPT2ULTRA I put in my house (which suggests being connected to a dedicated 50A two-pole circuit breaker). For our American split-phase system, it has both L-N and L-GND protection, and burns green LEDs while the device is still in service. They also have a model which only has L-E/N, but it's more expensive for whatever reason.

@leexgx

4 жыл бұрын

First ones used to be on a MCB but that's not required any more (just runs right off the consumer 100a isolator) as any type of amps and heat passing it melt off the solder and they cut off (for genuine spds that is as they normally only have a very small blodge of solder but they do get quite hot and they use low melting point solder ) the Neutral likely will never fail As its typically a gas discharge device but the live will always fail eventually, you can actually hear it sometimes if you put 1000v on constant test as it heats up the varistor

@jwflame

4 жыл бұрын

The types that don't require an external MCB have a fuse inside them. If that fuse fails, the SPD is useless, and no one will ever know because the fuse failing doesn't trip the mechanical indicator.

@leexgx

4 жыл бұрын

@@jwflame the fuse (normally solder as a fuse) is what is holding the indicator tab green, once it fails it gets hot and solder melts and disconnects it witch moves the tab to red, be it China ones or UK genuine branded ones

@jwflame

4 жыл бұрын

@@leexgx That solder link is a thermal overload, designed to break in the event of excessive temperature. They all have those. Types with a fuse inside have a fuse designed to fail at a specified current, they also have a fuse symbol on the side of the device, one example: www.dehn.co.uk/en-gb/1628/31262/Familie-html/31262/DEHNguardmodularwithintegratedBackupFuse.html

@leexgx

4 жыл бұрын

@@jwflame the 18th edition ones seem to have that fuse built into the spd (but very Likey still Just solder but very small amount or a fuse wire holding the tab green) I agree once it does blow it probably never get changed for long time as you could see that the MCB had tripped before (assuming the solder didn't melt first)

what about the chinese cheap dc spd?

strange coffee maker you have there john, it outputs 600 volts to grind the beans?

How safe is it to omit the MOV direct from line to neutral? Doesn’t this risk putting significant potentential on the earth in a TT installation?

@jwflame

4 жыл бұрын

Without it, protection will be significantly reduced. Risk of potential on the earth is no more than any other fault would cause.

@cjk32cam

4 жыл бұрын

Ah, so would this be connected ‘downstream’ of the main RCD? If so, I can see that it’s clearly the same as an earth fault on another final circuit. Moreover, I guess most transients are short enough (I think you said microseconds) that you’ll not dump enough energy into earth to trip an RCD.

When a catridge is placed is there continuity between Phase and Neutral and phase to earth and neutral to earth??

@jwflame

Жыл бұрын

No, in normal use there is no continuity or resistance. They only conduct when higher than normal voltages are applied, typically over 275V.

That soldered tab looks very long, would it move far enough out of the way to break the circuit?!

@leexgx

4 жыл бұрын

Low temperature solder and another youtuber has shown they do make a clear gap

@jwflame

4 жыл бұрын

Will find out in a future episode.

Great video as usual, very educational. I would like to know just how much of a real issue this is for the general public, what frequency of surges actually happen in rural and urban areas for example. Or is this an opportunity for the manufacturers to cash in... call me a cynic :-) Also, given the large amount of heat produced (enough to melt solder), what about units next to these (MCB/RCBO, etc.? Should a space be left between the Surge Protector and MCB/RCBOs?

@Mark1024MAK

4 жыл бұрын

Where I live, in my home, I’ve not known any electrical or electronic device that has failed because of a surge. However, the problem is that you are not likely to know if/when a surge has occurred. And when an electrical or electronic device does fail, you then don’t know why. All I know, is that when any of my electrical or electronic devices have gone faulty, nothing else has failed at the same time. Hence, if there has been a surge, it must have been rather selective!!! Where I work however, some outside effect (lightening is suspected, although not a direct strike, or possibility electromagnetic induction from something else) has caused surge arrestor protection modules to go low impedance, which did protect the communication equipment (linked by miles of long distance external telephone type cables) , but caused a loss of communication until we replaced or disconnected the failed surge protection units. The older design of communication surge protection units that we used to use, were constructed using two RF chokes (in series to the equipment), two 100mA fast acting fuses (also in series), back/back 12V Zener diodes across the lines, and a ‘three terminal’ gas discharge device (middle terminal to earth, other two terminals to line A and line B). In these, we mostly just had to replace the fuses after lightening storms.

Fluke max voltage is 600, right?

Your globe lamp stayed on in this video ;)

Hi John, thanks for all the videos. I've learnt a lot from you! Do you have surge protection fitted in your own house?

@jwflame

4 жыл бұрын

No, because it's an older installation and the property is rented so it's not likely the landlord would pay to install such things.

@literoadie3502

4 жыл бұрын

John Ward Thanks for the reply. I bet as an electrician, you would love to improve the installation in your own house? But the landlord won’t pay.

谢谢

Help! I get it that the SPD provides an alternative path for all the surge energy, but how does it prevent the overvoltage appearing at terminals within the installation? Isn't a resistance in the line conductor required to limit the voltage transferred to the installation? Great videos by the way, all interesting stuff … thankyou.

@jwflame

4 жыл бұрын

When conducting, the SPD is basically a short circuit across the conductors. Can be considered as an extreme case of voltage drop due to excessive current.

@markjohnson8390

4 жыл бұрын

@@jwflame Thanks for the swift reply. Sorry to be a bit slow here but … the overvoltage (emf) is presented at the terminals of the SPD and also across the terminals of equipment within the installation that are connected in parallel with the SPD. Therefore, how is the equipment protected? Isn't the voltage drop across all parallel loads the same?

@jwflame

4 жыл бұрын

The simple way to think about it is that voltage is current x resistance. If the SPD has an extremely low resistance (near zero), the voltage across it must also be very small, even with very large current. As an example, if the surge current was 25kA, and the SPD had a resistance of 0.01 ohms for the duration of it, the voltage across the device would only be 250 volts. In reality it's far more complex than that, but that is the general principle.

@nathan87

Жыл бұрын

@@jwflame Unfortunately I don't think this explains it though, because fixing only one of V, I, R in Ohm's law doesn't fix the other two. For example, for a 0.01 ohm SPD, why not take the surge current to be 25MA so that the voltage is 250kV? I must speak with some caution here as Electrical Engineering isn't my strongest subject, but it seems to me that the key here is to remember the source impedance, which forms a voltage divider with the load. Normally the source impedance is much higher than the load, so the voltage drop over the source is small. But in a surge, the varistor impedance drops, causing the load impedance to drop much lower than the source impedance. Now, most of the voltage drop occurs over the source reducing the voltage at the load.

@felipekersting7065

6 ай бұрын

@@nathan87 When you said: "Normally the source impedance is much higher than the load" you actually meant: "Normally the source impedance is much LOWER than the load", right? Anyway, yes, I see this exactly the same way as you. When I analyze this circuit, the only way I can see it working is when considering the impedance of the source/line, which will "absorb" the voltage drop in the surge scenario. If the source/line impedance is ignored, then there is no way this circuit will work, given that, even if the "resistance" of the varistor drops to 0.0000001 ohms, the voltage applied to the installation will still be equal to the source. I think there is a general misunderstanding on how this circuit works tbh, I am really trying to find sources explaining precisely how it works, but none of them cover this. Overall it seems weird to me that the protection relies on the parasite impedance of the source... but I can't see any other option for this to work...

So you dont need to connect it earth to work?

The basic principle of operation seems the same as a Zenor Diode protection circuit.