British plugs with built-in surge arrestors. (With schematic.)
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- čas přidán 9. 11. 2019
- I got these just to find out how they had implemented the surge protection in such a small space. It's an odd but also clever design that is based on existing electrical parts.
I'd guess that these would be useful in a situation where there was a risk people might unplug a typical surge protection adapter. If it's on a flex then it's less likely to get removed. But it's also less likely to get changed if it fails over time.
These units came from CPC (part of element 14) in the UK. I'd guess similar devices exist for other styles of plugs too.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
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This also keeps the channel independent of CZcams's advertising algorithms allowing it to be a bit more dangerous and naughty. - Věda a technologie
These are by PMS, Hong Kong company called PMS Ming Kee. They've been making plugs in the UK since at least the mid 80s but the company is 40 years old. You used to find them in market stalls but they've proven to be good quality and widely available under own brands such as CPC, Morrisons etc and found on many small appliances. The design hasn't changed since the 80s and they're generally one of the better plugs on the market (although they’re using cheaper plastics as time goes on).
Before PMS started doing this surge version in the 2000s, WG/Volex (in the 80s/90s) made a UK made surge protected plug like this.
D is disk type (size in mm) K is Tolerance +-10%
Thanks!
Ditto! Thank you very much!
D for Dont need no fuse ;-)
I love how simple it is, and the way it uses off-the-shelf standardised parts, like the spring loaded pins
Thanks for the video Clive :)
These seem like they are pretty good as surge protectors go, apart from their lifetime being fairly short if your lines are noisy. Most cheap surge strips I see in the States only bridge LN (no LG or GN), and many lack any kind of indicator of whether they are still actually providing protection. That this one also seems well-built and cleverly engineered is a bonus.
I remember back in the early days of PCs, someone wrote a column about adding MOVs to power strips to add surge protection. Within a month, most U.S. Radio Shack stores were completely out of MOVs. Soldering in 3 MOVs was simple, easy and effective, but I don't recall anything about adding thermal fuses. Unlike now, surge protected power strips would cost upwards of $50-$75, and were difficult to find because they were 'commercial' products.
Always love when Big Clive is surprised by a tear-down. "That's quite cleaver." Such a simple video but yet still entertaining. I'm getting more and more jealous from not having regular 240 volt here in the US.
Thanks Clive, great clear explanation as usual. Nice that you will look at some of the more overlooked items that we have around the house.
I like the image the camera you used on this video has given. It's a crisp clear focus, but a slightly warmer picture, yet the white is still a nice, clear white.
Sound is good too.
I do like surge protectors that don’t shut off when they stop protecting. I have never met a non electrical person that pays any attention to the light going out. But the beauty of this design was that they didn’t have to interfere with the existing plug design. I wonder if they could add a buzzer when it stops protecting. This would also help when the plug is out of site behind a piece of furniture.
I'd concur with that. I wonder how many surge protectors in use are actually providing protection any more. I seen a fair few that aren't. People just tend to assume the wouldn't work at all if that was the case.
I have found the surge protectors that offer an attached device warranty are the ones that will shut off when they stop protecting. I’m constantly checking family and friends computers to verify they’re plugged in to a proper surge protector. Since I’m going to be the one that has to replace their power supply. They are always so confused that I tell them their surge protector did not protect them when they were plugged into one that didn’t shut off.
That's a great improvement over the standard plugs! I'd love to see this in US plugs too.
I've had one of those on my computer power lead for many years, just realised I've never checked it see if the MOVs are still OK. It doesn't have the neon so no obvious outward indicator it's still working.
edit: had a quick look, it's a similar design but the components are potted.
There are actually MOV's with series thermal fuses integrated into a single package. Littlefuse makes them, makes layout and design or adding protection to an existing circuit very simple.
and this is why I read the comments, knowledge is power.
You've just given me another project to add to the list! I am busier now that I am retired than ever when I worked for a living!! Top work Big Clive!! hahaha!
i have used one for 20yrs now & never had a problem.. very interested in your video..
Very crisp sound with good bass. Keep this setup.
Clever analysis dear Clive
Re: Audio / Video equipment. Sometimes older is better. and this video is an example that shows that to be true.
Onwards towards 1 million subscribers!
Pretty neat design, especially the way it utilises a standard plug... :)
Very rich sound and good video - stick with it sir
I absolutely love the mic in this camera! So soft and bass heavy 😍
It's just the built-in mic on the iPad.
Rudofaux nope
Awesome video Big Clive, I wish we had these in New Zealand
I like the technical term you use 🤔. It may go boing 😉...
- but that's ok ;-)
Big Clive must be a Scot. The English would say "fatang". :-)
Hi Clive, great video.
The reason for the thermal fuses in contact with the MOV, would possibly be because when MOVs fail, they do as a short and usually split open.
So at sometime they probably get hot, the fuse is to prevent the smoke an flame from occuring.
Yes that is correct.
Once I saw a surge protector after lightning strike catch fire a little while afterwards.
Not at my place somewhere else.
Use the fire extinguisher on that one.
Also nice user image I see your fan of Lego.
On what Minifigures did that come from I'm sure it's an hodgepodge of them.
Are you with adult fan of white girl like me?
Nice, a new video on one of my favorite topics..
Go on swap the tops so you have two tone plugs :-D
That could look quite nice.
British plugs are just soooo huge. Glad Canada uses the small 120V plugs! :-)
Yes, so easy to grab the live conductors as well. No wonder the standard method to remove is to pull out by the cord, because the plug is small, there is no sleeved end and of course the sockets have no switches to disconnect them either.
@@SeanBZA - Yet as a Canadian I never hear about anyone touching the live connector. They aren't hard to pull out but true that some people are lazy and grab the cord. They take the abuse. 120V is great for the vast majority of items and we have 208 and 240V for the big stuff. We do have switched sockets but they are usually just for a lamp outlet on the other side of the room. Don't need it otherwise.
Haven't seen one of those plugs since 2001 👍
"odd but clever" describes CPC pretty well
one reason for incorrectly wired sockets is the fact that different makers put the connections were they like so if someone goes to b+q or some such and gets nice new shiny sockets , switches off the power and removes old socket and fits new socket they will just fit the wires same as old socket which may have L + N opposite way round , when they plug something in to test it works , job done :-)
Interesting video Big Clive
For some reason the picture is sharp on the right side but unfocused elsewhere. It's quite apparent with the notebook in view.
This is a common anomaly on phone cameras
picture quality is fine, but zoomed in a bit blurry. softer than it should be
They look like a good idea, if they go the top half can be replaced without disturbing the wiring. I've got the power strip embedded type here, no issues so far. As for your domestic sockets - a case of Part P kitchen fitters ? Not that I have anything against kitchen fitters, just believe their bloody hands should be cut off if they play with electrics ! Discovered in my kitchen 2 sockets in 2.5mm T&E and 1 in 1.5mm T&E all in a 15 amp choc strip. Earthing cable to the earth rod had been cut to get a unit flush to the wall. Thank god I still had a metal gas pipe. New earth rod and wiring done straight away.
There used to be fridge power loss alarm plugs that used a similar construction.
Hi Clive,
Mov's break down over time and end up leaking a current to the neutral. I've always sold an low currant circuit breaker to be installed in series, mainly as a cost saving so the surge protector doesn't waste power. Maybe that is why the thermal fuses are there.
I was expecting ".. it might go boingg --- but that's ok"
Got a 33D00061 unit, which is rated for 480VAC. 470VAC will not clamp most small pulses, but will do big ones. you only need 2 thermal fuses, as they only need to disconnect 2 out of the 3 wires at most for the unit to not work.
I have made many DIY versions, using a single MOV, 275V, inside a standard 16A plugtop, as they do work well to clamp spikes. The MOV units tend to fail short circuit and trip the breaker, but here the breaker is 20A, not a 32A one used in the UK, where you instead use fuses in the plug instead. Not sure which system is safer overall, both have pros and cons.
I like these, use one on battery charger/transformer in caravan, very useful when using a generator.
I must be missing something. The standard plug base connects the cable of your device directly to the outlet through the fuse. How does the additional PCB bit do any protecting if it can't actually break any connection?
It doesn't break the connection, it just sits in parallel with the load and shunts any excess supply voltage to earth.
Dave Pusey, Ah ok. Thanks for explaining.
@@davepusey Thanks. I feel like, unusually for Clive, the video was rather lacking in explanation for how it actually works.
@@davepusey Since there is a thermal fuse in series with the MOV, it would probably blow the thermal fuse and protect the MOV during a surge. The connected device will still be connected to the outlet without any protection.
If you have some spare tops, you can replace them when they get damaged.
Also; I thought they often used LEDs because if you get a spike big enough to destroy the LED, then there is a good chance that the protection has failed?
You may have a point there but it's probably because the car me and stuff but I don't know anyone that guy comments on that?
Need to check if there is a shucko F type with MOV, but mostly the F type is big a bulky plug-in socket. Not to say that the british plug is bulky by any means, since it carries a fuse holder just in case.... as for the MOV reference search the part number and check the datasheet, first pages, eg little fuse.
Mic is very crystal clear with voice.
big clive!!!! i found you bc i am trying to reprogram some lights i have n had a question..
i have two strings of lights, led it think, with little control boxes with buttons to change the settings, they can plug together, but don't change to the same setting when one is changed. is there was way to change that in the boxes or would i have to wire them together? thanks!!! these videos are rad
I love your videos, question for others, getting sound on adverts but not bigclives videos on pc, but okay on tablet, any ideas tia
@Matt Quinn thanks so much matt, don't know how that happened, much appreciated, took a bit of fiddling but sorted, not the same watching it with subtitles, lol
If I understand this correctly, it will also protect other devices plugged into the same extension lead or those very close on the same ring main?
Yes.. no.. maybe? Probably erring more towards yes, but it's a fairly basic level of protection to begin with.
The connection is pogo pins or spring loaded pins, they are becoming more popular with electronic manufacturers as the board connection is just pads ecthed into the circuit design and no cost in parts so the programming connector or test connector is pushed against a set position and makes the connection.
The color temperature of that camera looks very nice. It's an inviting warm with nice balance however the focus on the other hand seems a hair dodgy. It's sharp as can be in the upper right but the left 1/3 of the image seems quite soft, especially toward the bottom.
FFS-It's a neon indicator !- Sheech !!
@@davidworsley7969 Too much coffee, lad. I was referring to the picture quality. Did you get enough sleep?
@@Peter_S_ You were ?....Well.....Who'd have thought ? ZZZzzzzzzzzzzzzzzzzzzz.
@@davidworsley7969 When is the last time you saw a neon indicator that had a sharp image in the upper right but the left 1/3 of the image seems quite soft? Doesn't add up.
@@Peter_S_ You woke me up to ask me that ? Where is your humanity ?
What lamp holder is that with the spring loaded pins? I don't quite get it
Any you push & twist the bulb to fit it. Normally referred to as 'bayonet'
upload.wikimedia.org/wikipedia/commons/f/ff/Bayonet_lightbulb_and_socket.jpg
Best of best. Thanks. Thank you so much.
Clive i was thinking that why they are not using 10d371k mov.voltage will not go above 370v.
Because with 10% tolerance a non-trivial number will conduct every cycle, and even those which don't will have short lives.
Plus, the greater energy dissipated will cause more heating of the MOV and shorten their lives even further.
This explains why surge protectors can be a fire risk after initially protecting a surge event
Sound good. Image seems to have a gradient from left to right. Right side being more in focus. Colour a tad too rich. Great VDO as always.
I'm quite happy with the colour.
The US has different grade plugs, Hospital, Industrial, etc. does the UK have similar grades?
No sound for me when 5.1 audio selected in Win10. Needed to switch to 2CH stereo to get sound in this video. All other videos work fine with 5.1 selected
New sound for sure. Like it, voice better matches your insignia.
If either of the fuses blow? Shurley if just the Nuteral fuse blew the neon would stay lit, would't it?
Possible, but also unlikely. For that to occur, the Neutral to Earth MOV would have to be shorted.
Is there any way of demonstrating or showing them actually working? Maybe one for John Ward?
Clive has the insulation tester which goes to 1kV or more if i'm right.
it should clamp down to around 270V then.
@@PsiQ Being 470V MOVs, I'd go with closer to, uh, 470V.
@@Monkeh616 um, aah, was thinking of the ones i've seen lately which were rated at 275V/1mA i think
Was it 230V +/- 10% for allowed tolerance ?
(Wouldnt work for 230 x 1.4 peak hmmm )
@@PsiQ Something rated at 275V was probably rated for AC - which makes it a 390V part.
Are we getting these and the surge protected sockets for when every person is driving an electric car and gets home at 6pm and plugs in the car and makes a cuppa tea and we get a huge surge?? :-)
I once heard about how bad knock off apple chargers are and I did buy one off of ebay, so I tore both the original and knock off apart. Man, the differences in them! I do not know a lot about circuits, but the difference was night and day.
Those brass springy bits are popularly known as "pogo pins".
but brass springy bits sounds way better
It's not what they call them in the railway industry. There, they call them.....
....BUFFERS !
@@millomweb Thanks, I LOL'd :-)
@@theskett It's true ! I should have gone to bed an hour ago :)
How common are power surges? Is it usually caused by a home appliance or does the surge originate from the supplied mains? Thanks!
Often appliances with high inductive loads like motors can cause spikes.
There's nothing like standing on the pins of the delightful British plug in the dark.
It makes you and everyone else in the house feel alive as you shriek scornful abuse at the idiot who's left a stray plug or two like a Vietcong spike pit. I had to scumbag brothers who'd make such traps for each other and I was often the victim of their wars!
Hi, do these surge protectors stop surges in both directions? I ask as my freezer is on same double socket as my PC and every now and then when the freezer motor kicks in, I get a blank screen and I want to fix that!!!!
It's probably the slight voltage dip cause by the fridge compressor kicking on. Not something a simple filter will help with.
@@bigclivedotcom thanks... I know I can't expect you to... but can you suggest any potential solutions? Its annoying RN but if I want to game its gonna be a "game changer" in all the wrong ways!!
you could just take an existing plug and swap the back rather then rewiring the entire plug pretty cool
Does anyone know whey it uses a neon indicator as opposed to an LED? I'd suppose the LED is cheaper and lasts just as long? CMIW.
Neon indicator doesnt require stepping down the voltage, just throw a small resistor in. makes it cheaper for simple things that aren't using a transformer or voltage dropper of some kind to begin with.
@@SenorBolsa Thank you for the explanation 🙂👍
Can we buy OnLine please?
PTFE tape wrapped around an eraser is a really good source of pure white for white balance correction without having to pay out the nose for a WB block.
Is WB such a big issue ?
I loved the way filming grass from under a blue tarpaulin turns the grass yellow.
Nice one
But how clever/large is the available contact surface area between the rounded pin tips and the bottom part? These could get really hot when maxed.
They don't carry any relevant amount of current in normal operation..
@@Monkeh616 "in normal operation" which is what, charging yer phone or heating up yer caravan?
@@Io1564 Doesn't matter. The load current of the device does not go through those contacts.
Interesting, so not an in-line protective device, but more like a voltage-detecting shunt?
Yes. Just shunts transient spikes.
@@bigclivedotcom Would they protect against a nearby lightening strike? Is so I will buy a few for my computers etc.
Excellent video, thanks Clive.
@@gromett Are you asking if the computers will be fine after the house has been vaporised by a lightning strike ?
I suspect the first thing you should do is assess the likelihood of a strike.
This could be an interesting consideration for when I next trim the trees.
@@millomweb
he did say nearby strike :-)
but it would be impressive if the house was blown to bits and the computer was standing there good as new :-)
@@gromett Power line surge suppressors alone won't save you, you need proper grounding so surges don't travel through alternate paths such as AC->PC->HDMI->TV->STB->coax. For higher value equipment, I'd rather have a better-rounded surge suppressor with in-line chokes (ex.: Tripp-Lite isobar) to soften transients and give its multiple 20Dxxx MOVs a better fighting chance against whatever is left.
My concern with this design is, is the live going into the surge protector is after the fuse, not before. So if it starts dumping power, is that going to trip the fuse in the plug, preventing the surge protector from doing what it should do? Shouldn't it actually be without a fuse, and without the possibility of wiring to an appliance?
It occurs to me that if you just plugged one of these into the sockets at each end of a ring main, then it should provide reasonable protection for everything else plugged into that ring. There's no need to actually wire them into any appliances unless you're short of sockets.
Remind me where the end of a ring circuit is again?
@@Monkeh616 end of the house and start of the house, I guess having one plugged into each room would work as well, the more you have more likely they adsorbed the spike over each spd
but generally they more effective if they are before the device that is been supplied like an extension cable with all your electronics plugged into that (or in the consumer unit as is starting to happen )
Belkin with there surge master line socket and 4-8 way extension leads having doing it for a very long time
@@Monkeh616 The two ends of a ring main are the first socket and the last socket going clockwise or anticlockwise in the southern hemisphere.
@@petehiggins33 First socket from where? It's a ring. And yes, I appreciate you mean the first one along the run from the CU. These really only provide very, very basic protection, though.
@@Monkeh616 Clearly it would be better to fit a proper surge protection device like this tinyurl.com/r8a2vpf in the consumer unit but they are expensive and should only be fitted by an 'electrician'. But if you were thinking of using these relative cheapies to protect a couple of appliances then my suggestion would give the same level of protection to all the sockets on the ring for the same cost. You need to use two because the transient will travel in both directions around the ring and the suppressors will only protect sockets downstream of the wiring.
Hi.Where can I get that online?
It came from a UK supplier called CPC.
Not totally keen on the spring connectors, a high resistance connection between the screw head and the plunger or between the two sliding parts means the surge protection wouldn't be effective but could still pass sufficient current to light the neon.
nice use of your giant plug
Could you use it on the front end of an extention cord?
Of course, but you may as well get one with more substantial surge protection built into it..
I'd rather use it at the female end, to get the length of the cable to take the power of the transients when the mov's clamp down.
@@LeifNelandDk You can certainly do that, but there's not enough impedance in the extension cable (otherwise it'd get hot...) to make any significant difference.
Do varistors clip voltage??
Yes. They conduct above a voltage threshold and are intended to clamp short duration voltage spikes.
Efficiently made and seems to be of good quality. I have not seen a similar product in the US. Here I have only seen large MOVs on poser distribution strips and backup power supplies. Usually the whole unit is thrown out when someone notices the neon has gone out. That's a lie. Nobody ever checks the neon.
I do check and replace MOVs. I have heard MOVs wear down over time, with every tiny overvoltage hit eroding the internal bits a little. Don't know if that's true.
They do fail progressively over time with each transient absorbed, just as you mentioned.
@@bigclivedotcom Can they cause ghost RCD trips when they age then?
@@uK8cvPAq They can, although usually they're terrifyingly hot before that occurs, which is where the thermal fuses come in.
In which scenarios should one use one of these?
Anywhere you want a little extra protection from mains borne spikes and transients. Like a computer.
Clive didn’t checkout the “D”! Well, there’s a first time for everything, rofl
Sprung contacts make for ease of manufacture, but what about risk of substantial volt drop across contacts during a high-current burst?
The spring contacts are maybe 100 milliohms. The MOVs kick in at 470V. You're not going to get 4700A in any domestic environment, so the spring contact resistance doesn't matter at all.
Spring contacts are, say 100 milliohms but are inductive and so their impedance to fast transients will be way more than 0.1Ohm but yea, all good either way
I can't trust MOV. Is it really effective?🤔
A guy tested MOVs, spark gaps, clamp diodes, everything failed except the MOVs. The MOV clamps the spike immediately with absolutely no overshoot. I am not an expert but I heard here and there that MOVs stop working after they receive certain amount of spikes through them. They conduct and overheat and start a fire, that's why they go with thermal fuses. Maybe a ferrite filter is a better option? Maybe a small cap with discharge resistor after the MOV is a good idea, it would take the energy of the spike but would not let it overheat if it fails. Oh wait, that's too expensive ... you know how it goes, plastic metalized wires are our future! :)
I can't figure out how you connect the "flex" from your device into this plug. Am I missing something? Doesn't the power need to go through the protection before it goes to the device?
The protection is in parallel it clamps voltage spikes.
I want to know how a complex surge protector with filtration works as opposed to this simple one. Like a Thore surge protector...
Interesting, I don't quite follow how it protects against surges if it's just touching the screws on the wire connectors. Doesn't that mean any surge can just go down the wires unimpeded? It's not between the mains and the appliance as far as I can see so I just don't get how it works.
These are metal oxide varistors , if you connected one in series with your equipment then it would get 0 power unless there was a spike then it would get the spike lol, and go back to being off. Basically giving you only spikes.
Think of a how a diode is like a one way check valve, these are like a 2 way 'check valve' but with a very stiff spring (though they are not built with diode it's just an analogy)
Put some aircon in a shop where the incoming live and neutral were reversed! Customer wasn't bothered, suspect they'd bypassed the meter...
So was the meter running backwards ? ;)
I'll do you one better. My boss sent me to one of his rental properties to take a look at why the circuit breaker for the barn out behind the house kept blowing. He had just had some work done there by a "professional electrician." Now, for purposes of understanding the problem, I'll explain a bit about American electrical systems. Most devices use 120 volts, and larger devices such as air conditioners, ovens, etc. use 240 volts. The transformer that supplies the property has a 240 volt secondary that is center tapped, with the center tap being referenced to ground (Earth) and serving as the neutral on 120v circuits. The two live wires go in to the circuit breaker panel (consumer unit) and the bus bars alternate so that every other slot uses one live wire and the others use the other one. For a 240v circuit, you have a double pole circuit breaker with one pole on each of the live wires, so that they have a potential of 240v between each other. When you run electricity to an outbuilding, you'll run 4 wires: live 1, live 2, neutral, and ground (Earth) Those will go to a sub-panel with circuit breakers for the outbuilding, and a large, double pole main breaker supplying that will be in the main breaker box in the house. Back to the story. The "professional electrician" that had done the work previously had installed a new subpanel in the barn. In the process, he had connected one live to one live busbar, as you're supposed to, the other live to the neutral bar, and the neutral to the other live bar. Being a subpanel, the neutral and ground aren't bonded together- that's only done at the service entrance, otherwise you can wind up with the ground carrying current. So the installation didn't just short out as soon as power was connected. The result was that half of the outlets and lighting was wired with reverse polarity, and the other half had 240v instead of 120v. Naturally, the things that were plugged in to those outlets didn't like it. So someone else was sent out to see what was going on. Upon discovering that half the outlets had 240 volts, did he go and look at the panel to try and figure out why? No. He just disconnected those outlets and connected them to the circuits that had 120v, and called it a day. So now, you have reverse polarity at all of the outlets. Long story short, there was a security light that comes on when it gets dark that had been connected to one of the 220v circuits, and was damaged by that, such that it had a short circuit in it when turned on. So every night, it would blow the main breaker- because the circuit breakers in the subpanel were connected to neutral, where they were essentially useless. Fortunately, nothing disastrous happened, but it did take me the better part of two days to 1) figure out what the hell was going on, and 2) get it properly sorted, since I had to rewire half the outlets to connect them to the proper circuits.
I might be asking a silly question I'm tired after being dragged around in the sunshine by the wife all day, (I'm on holidays in Spain currently) but if its a standard plug base and the circuit board just sits on the three pins monitoring, how does it surge protect? Surely if the surge protection fails the device connected will keep working provided the 13a fuse is intact.......
Clive again apologies if I'm missing something or asking a dumb question.
Regards
Brendan
The MOVs are in parallel with the appliance to be protected, so should shunt out any high-voltage transients. At some point, the MOVs may reach end-of-life, become conductive, trip out the fuses; at that point, the neon will no longer light and (if you check the neon) you'll know to replace the plug-top [so as to get some new MOVs].
It's not exactly fail-safe (!! :-) but it's probably better than nothin' :-)
Nearly all "surge protectors" have this problem, they are parallel connected and do not disconnect the appliance when they fail. So they may absorb some surges, but if a really bad one comes along it will blow out the surge protector and continue it's merry way on to the appliance.
So instead of having to rewire your plugs, you could just replace the back of the plug. Nice.
Franko Walker yea it is useful
Pictures in this video seems a lot less sharp than usual, have you thought about trying 4k?
4K would be difficult to upload on the outdated Internet services here. I think the camera I was using here was over compressing the images.
Presumably those springy pins are rated over 13amps, since they may have been designed for a lamp fitting I am not so sure..
How about an older model GoPro to film? The more recent models allow live previews, streaming, and controlling the camera from a phone.
Too wide a view. I tried one a while ago.
@@bigclivedotcom too wide isn't a big issue, but I just remembered you post videos with minimal video editing.
I bet you could ask us to sample what phones we have. I'm sure some us would be happy to help. Tells us what height from bench, recording area, video camera features needed.
I don't understand how the MOV marked with a star (between N and E) is any less protected than the MOV between L and E?
possibly due to the location of the 2 thermal fuses, one mov doesnt get one.
@@waldsteiger but it's symmetric?
If you have reversed polarity and that MOV fails, there is no thermal fuse to act on it - the one carrying the current is located under the wrong MOV. The fuse will likely still end up opening eventually, but it's not an ideal arrangement. This is however a relatively small risk - we have polarised plugs and generally polarity is correct in our installations.
@@Monkeh616 there's a thermal fuse on both the live and neutral terminals. Whether reversed polarity or not, no current can flow without going through a thermal fuse?
@@yadt the movs are not protected. its when the mov is already dead or dying (they get hot), then the thermal fuse cuts out to protect the load.
I'm still getting to grips with surge protectors but I do wonder, if they all have a limited lifespan, why are they even built in to some extension leads when I'm assuming they're not easy to replace that way? It would make more sense to me to take a normal extension lead and change the plug on it to one of these plugs with a built-in surge protector, and then when that protector fails, you can simply buy a new head, or is there a reason that's a bad idea?
You could do that. A surge protector should last a long time if it isn't on a very spiky supply.
Looks like someone was thinking when designing the plugs.
Yep and say so.
How do they protect you device when all the protection is sat on top of the plug and the wires go straight from the plug wire and straight to you device if the protection blows the plug will still work .. i don't get how it protects say my computer against a power surge any power spike is going straight from the power out let onto any device plunged into it
When a power surge occurs those MOV´s short out the plugs. So the electricity flows through them, and not into your device.
When a power surge occurs those MOV´s short out the plugs so the electricity runs through them, not into your device.
@@SharkoonBln thanks so it blows the fuse then in the plug
@@Rob1972Gem Those MOV absorb the spike. They get hot while doing this, so they will be fine absorbing spikes, but no long occurence of overvoltage.
@@Rob1972Gem No, it shouldn't.
These are for transient overvoltage protection - very short durations, nothing like enough to blow a fuse.
SUR(GE)! YOU’RE UNDER ARREST!
Currently. I'll break free, someday!
You can't resist me forever.
Watt’s the charge? 😁
Is there any case where polarized plugs actually are a benefit rather than creating a new safety hazard by relying on the polarization?
They are always safer as the live is the wire that's fused and switched inside the appliance. Unpolarized plug, appliance switch off, appliance 50% chance of being live inside.
@@MarkTillotson Which is irrelevant as there's such a thing as isolation. Functional switching is not the same thing, and if the two are a confusing concept you shouldn't be inside the appliance..
So if I understand right, this is more for indication than for protection, as the connection is never broken to the device, but the neon indicator goes out when there has been a surge? It wouldn't actually protect your equipment from said surge but only provide evidence that there has been one?
It will shunt spikes and transients. It wouldn't deal too well with a direct lightning strike.
@@bigclivedotcom Very little does, really.. Lightning has a tendency to win.
@@bigclivedotcom I feel like I'm missing some basic knowledge here because I can't see how a circuit can protect a device while the circuit to the device remains in place, if you know what I mean. Don't get me wrong, I'm not saying it doesn't work, I just can't see how it does work.
@@Akira42 The MOVs become temporarily low-resistance when the voltage rises high enough to trigger them, causing a temporary short circuit. Because the electrical wiring has non-zero impedance, the short circuit causes voltage drop in the wiring, dragging down the voltage and protecting the appliance. Normally this will only be for a very short period of time (milliseconds).
Considering each MOV individually, the wiring and the MOV together form a potential divider across the origin of the voltage spikes. When the MOV is not conducting, its resistance is much, much higher than that of the wiring, so most of the potential difference (voltage) is across the MOV and thus also across whichever parts of the appliance the MOV is in parallel with. When the voltage rises and the MOV begins to conduct, the MOV's share of the total circuit resistance falls, and thus its share of the potential difference also falls.
(Someone correct me if I'm wrong.)
@@patrickwigmore3462 Thanks for explaining, I think I get it now. The devices don't get 'in the way' of the surge, they draw it away from the equipment instead and dissipate it, I guess is how I would put it?
Why do british plugs have a fuse ? Most other countries (that I know of) do not have fuse in the plugs.
As far as I know it's a post war thing when there was a copper shortage so new homes had a ring circuit configuration requiring all plugs to have their own fuses for protection
British socket circuits are in a Ring Topology to increase capacity and save copper. This increased capacity is far more than is safe for any flexible cord. The overcurrent devices having the increased capacity will not reliably trip quickly enough if there is a fault involving a cord increasing the risk of fire. By adding a fuse in the plug the British were able to safely use smaller cords on their appliances without the risk of fire in the event of a fault. A fuse is also required whenever there is a spur off of a ring in fixed wiring.
Because of relatively high current (30/32A) ring final circuits. A small flexible cable (up to about 1.5mm²) could fail catastrophically under such currents, so they're fused at the plugs. Most other countries will use 16A, sometimes 20A, circuits, which even a 1mm² or smaller cable is likely to be able to sustain for some time.
It's a regulation. UK standard. Very thoughtful of them!
@@jrmcferren No, a fuse isn't required for a spur. 433.1.204.
In one of his video, Photonicinduction stated that English electrical equipment are among the best in the world, maybe he was right..
The Welsh, Scottish, and Northern Irish stuff is equally as good.
@@speedbird073 The Manx stuff is OK, too.
If the US upgraded to an accident reporting protocol that produced and published statistics comparable with British statistics, we could easily tell just how much better.
Note that the current US administration is actually working to reduce the gathering and timely publishing of accident statistics.
@@speedbird073 Cornish and Isle of Dogs too
@@speedbird073 I'm in North wales, electricity hasn't reached us yet. Got a few barrels of whale oil to use first.
is this video supposed to be muted or why is there no sound?
Check your surround sound settings. Dolby will be sending all the audio to a missing middle speaker.