Do you know what kind of tests and QA manufacturers do for their MCBs, and RCBOs? My guess, is that this issue should have been detected by measuring voltage drop at 40A.
I had two (Home and Work) Rolec car chargers when we first got EV (5 years ago). Both burnt out, one distorted the outer case too and was no longer waterproof. Breakers changed under warranty but at considerable inconvenience/cost to the installer (and me somewhat until it was fixed).
The general concensus is to replace them with a Garo RCBO - RCBOGRB40 I did this with mine when mine blew & it's been fine ever since. Although it did take 4 years for my Rolec one to burn out.
How much do these breakers cost? Can’t one install some better grade units from an industrial catalog? I’d expect a decent DIN rail branch circuit rated breaker (no RCD) like that to go for at least £100, although the best quality ones would be closer to £200 (I’m translating US prices and adding VAT). An RCD+breaker combo I would trust would be more like starting at £200. I’ve never had those fail, and have well over a thousand of them in the field.
Thanks Again BigClive. I believe you made this failure mode completely understandable to me. Pretty melty. Maybe not change contact itself but the flipping plastic capturing it. Another great Patron Video for us. Thank you Jordan also.
The main issue with EV charging is it's drawing a heavy load for an extended period of time. I doubt most (any?) EV onboard chargers have poor power factor as that would cause problems on the network so I'd be highly surprised if the applicable standards don't specify a pretty good PF. One OBC I took apart definitely had power factor correction.
Yeah, any respectable design will have a small inductor between the PFC stage and the network to prevent the "spikyness" described in the video, and that results in a pretty darn good sine wave.
Some newer car chargers supply the main battery with pulsed DC to eliminate the need to do full PFC in the car charger - the Li-Ion battery doesn't mind if the charging current has a sine profile.
It seems odd that it would have an issue with a heavy load for extended periods given the loads of old GEC units was greater than current car points and I've never had issues with them. More often it appears to be the on board dc conversion throwing issues back upstream. From personal experience I've had more customers with Telsa's have issues with the Relec points than Nissan Leaf and Renault Zoe owners. Not had any issues with the Zappi units yet though.
@@hugoboyce9648 Actually you would want to add a low-value capcitor after the bridge rectifier and before the APFC boost stage. From the IR1155s APFC control ic app note: _The purpose of the high-frequency capacitor is to supply the high-frequency component of the inductor current (the ripple component) via the shortest possible loop. This has the advantage of acting like an EMI filter, since it minimizes the high-frequency current requirement from the AC line. Typically a high-frequency, film type capacitor with low ESL and high-voltage rating (630V) is used._ _High-frequency input capacitor design is essentially a trade-off between:_ _· sizing it big enough to minimize the noise injected back into the AC line_ _· sizing it small enough to avoid line current zero-crossing distortion (flattening)_
Never knew about the "magnet thing". Really interesting (as usual), those breakers are pretty packed with components, and "a bit charred inside" may be an understatement!
In an old data center (circa 1995), we had panels where overloading one circuit would trip the neighboring breakers as well. Such is the price of "fancy" magnetic breakers. I don't see many of those anymore.
Yeah, like the 'magnet thing' design. So the current in the coil doesn't have to develop enough magnetic field to actually pull in a solenoid armature or anything. Just enough to oppose / weaken the field of the permanent magnet.
Clive, as others have commented I think you have a few things wrong in this video. Power factor corrrection circuits do not draw large current spikes unless they are faulty. Their whole purpose in life is to draw a roughly sinusoidal current in phase with the mains voltage. The do this by using a high frequency switch mode boost converter to supply the main converter with a voltage high than the peak mains voltage and modulating the power they deliver to be proportiional to the mains voltage. The high frequency component of the input current is filtered out leaving a 50Hz sinusoidal current. Also the circuit at 15:50 couldn't possibly generate a dc voltage to drive the solenoid.
@@mica4153 yep. It is a grey resistor surrounded by grey plastic, but still... he even kept saying it should be connected to the red wire, but didnt trace where it went, lol.
What I find incredibly interesting here is, all the incredibly thin wires, tiny sensing circuitry, low melting point plastics in the trip mechanism (all of these designed to be the weak point failure points) didn't fail. Nope, it was the beefy bigger current flow contacts that failed (from arc-ing because of uneven contact surfaces) and the heat resistant outer shell plastic that melted, causing more contact failure from plastic residue spitting on to the contacts, and eventually causing enough heat buildup to trip the bimetal strip microswitch. I wonder what would have happened if the melted plastic had glued the main switch contacts together more firmly instead?
I did my EV course recently. On it was a bloke who worked for rolec in the past. According to him: 'They buy a container load of the cheapest Chinese breakers/RCDs they can and print a Rolec logo on them."
Hehe, I also subscribe to Artisan Electrics. I'm a trained electrician from Germany and find it very interesting how things are done in other countries.
Finally the follow up or any follow up. Watching drain addict I'm always disappointed when there's something that needs to be followed up and it just ends
@6:19 "It's almost like it... before popping in." That's exactly what it does. It snaps closed fast at the last bit to minimize arcing. You should see high current, high voltage breakers doing it - it's... deafening!
15:11 - Reminds me of a gadget I got for Christmas as a child: Crdl (quote from the box: "It Rhymes with Fiddle.") It was a black plastic base with internal magnet, and a small pile of diamond-shaped metal bits you could, theoretically, make sculptures with.
Clive, I am not sure you apply power factor issues appropriately here. Even with the blocky simple circuit the power factor will be pretty much perfect . The current is in phase with the voltage, all be it with a different waveform. The problem with switched mode power supplies is that they reduce the size of the capacitor (to save space). This mean that to deliver constant power, they draw more current at low voltages (P=IV) and *only* smooth out between pulses, not half cycles of the supply. A power factor corrected charger (as you mentioned) will correct for this.
Of note: there are two types of power factor: the usual kind, where current is out of sync with the voltage, and harmonic power factor, where they may be in sync, but the current has higher frequency components in it. The power factor from the capacitive droppers is the second kind- that "pulsy" current wave can be represented as a sum of sine waves at multiples of 50Hz, but only the 50hz provides useful power, the rest just add extra current into the system causing various issues depending on the remainder upon division by 150
The contact tips used to be high quality silver and had a wiping action when they opened and closed to ensure a clean surface and in the case of DC rated contactors and breaker used a permanent magnet to help draw away and extinguish the arc over the arc shields and reduce spatter and grud forming on the contact surface. The newer devices seem to be moving down the path of cheap and nasty with material that tend to end up giving way to high resistance connections and failure, engineered obsolescent to promote further sales of more land fill. While recycling is the mantra way too much just become wasted resources ending up in landfill.
I was thinking of getting a Rolec charger installed on my Garage since my new electric car is due in a few months. Everyone on the EV forums basically said "no" and then I was linked this video (plus many, many pictures of exploded Rolecs). I don't exactly feel secure connecting a giant lithium bomb to one of these now...
High frequencies, perhaps start getting skin effects where the core of the conductor carries less of the current than the surface. Not so much a problem with small wires at kilohertz but as things go faster ... Also the magnetic fields from the current pulses may be creating forces which make the contacts resonate and start bouncing...
We have so many bad breakers in Canada from Bulldog/ITE, Federal Pioneer, and Sylvania. So many prone to blistering and failing closed and just no longer closing. Some burning the buss bars in the panels
Are the breakers being used as a disconnect instead of a switch designed for disconnecting under load? One of our buildings had the lights only connected to a breaker instead of light switches and the breakers would fail often until proper switches were installed.
I was thinking along similar lines: has the EV-user/owner been using the RCBO to interupt charging and therefore the contacts are breaking 7kW once or twice (maybe more) every day - NOT what they are designed for...
so if i glue a magnet to the door that presumably covers this, the breaker will trip every time someone closes the door? and even changing the breaker won't help?
Id be interested to know what Electric car this was charging in theory no EV should draw more than 32 amps AC as the cars on broad charger doesn't allow them to some EVs are only 16amps. However the Renault zoe is able on the Q motor to take much higher loads on a 3 phase supply it will happily go to 43kw. I've seen a zoe on a single phase draw over 7.6kw on some chargers for breif moments. Am currently reviewing EVERY EV charger in the UK Rolec still haven't sent me there unit for testing....
You mentioned that a bit of plastic which had melted had made resetting difficult, I wonder if a combination of poor connectivity of high current creating heat deforms the plastic making the connection worse compounding the problem until failure..
How about a line or load reactor typically used in line with 3 phase variable frequency drives. Would one help to smooth out the current at the breaker?
A few years ago I built a small device that I would use to annoy my parents (I am only 18) by remotely tripping the master circuit breaker. It consisted of a battery, electromagnet, MOSFET, and ESP8266. The ESP8266 (WiFi enabled microcontroller) would drive the MOSFET via a BJT. The MOSFET controlled power to the electromagnet, which when powered would cause the breaker to trip. I hid the device behind the panel where it could not be seen and would activate it remotely.
Had a look at the AE video. One of the things he did was fit a piece of plastic pipe to a close by water tap so the tap was isolated from the house earthing system. As a sparky, he forgot to connect the tap to a supply of plastic water too. Had he done an insulation test on the tap, he'd have realised the other error.
In the USA we have to use arc fault breaker’s in bedroom circuits. Are they similar to anything you guys use? My understanding is that they are different from GFCI breakers.
Yeah because of that research I now look at magnets like they are electricity since you are such an educated electrician I figured just telling you this would be enough to give you the Revelation you need
on many EV cars you can set the current draw, but like with most things people tend not to RTFM, as it is the vehicle that does the conversion to DC and charging of the battery, the box on the wall tends to just turn the power on and off from a signal from the vehicle. from the looks of it, the load limit on the vehicle is set just to a whisker of the overload limit.
Clive I like your videos and I was a research scientist working on a brand new electric motor I can tell you exactly how it functions and let me tell you there is no need for rectifier
I bet you'd love to teardown one of the new AFDD's, some of which have fully fledged microprocessors in them that would shame the first IBM compatible PC that I had!
the input of a high power device like a car charger should not look as spiky as you depict it, without those crazy 60 amp spikes. It should basically just be a fair bit of ripple, while the current curve largely follows what you'd expect of a purely resistive load.
Thanks for the explanation about the spikey current load - this explains why my microwave (which has a switch-mode PSU) makes a strange noise when my EV is charging. Ps. Apparently the Renault Zoe uses the motor coil as the inductor in the charging circuit to save weight. 🤓
I am having a tethered 7.2KW Rolec installed but I will be dialling down my EV's internal charge rate controller to receive a maximum of 12 amps. The charge rate I choose will broadly match production from my solar PV system on the day. Would such a light load over a maximum 6 hours (two or three times a week) extend the life of the circuit-breaker, in your experience?
This is a really compact device actually. Nice engineering. It is a single pole breaker tho, so be aware of that. I think the issue was poor manufacturing of the brass part. They are probably cast, and then roughly machined. If there was a burr on the edge, and not smooth, the burr would prevent making the full contact of the two parts. Good QA with passing 40A and checking the voltage drop, to measure resistance, would detect this. But I guess, they are skimping on that.
In my opinion, this fuse was burnt due to long time over current Condition. Most people don't expect what ther actual current draw really is. If this would only have used with a car charger - in Germany the Current Limit for that is about 10 to 16A @ 230V. I think this kind of load should not result in a picture like we see here. Most of the time, the fuse for the garage is also used for the cellar. So if there is a washing machine (10A), electric heater(16A), some hobby or garden related objects (8A) and finally the car at 16A we get a total current of 50A. In this unlucky situation, the OverCurrentProtection might not trip, even after hours. But the electrical overload will lead to early failures like this. Of course it makes sense to buy a reliable Circuit Breaker, but if you use it wrong, only luck can tell how long this works properly.
Sorry Clive I believe your understanding of the current drawn on a PF corrected supply is not correct, the current spikes on the old style supply are huge to charge the capacitor when the mains is above the capacitor voltage. The whole point of the PFC types is to spread the current pulses across the whole period. I would personally guess that that breaker was running at or near it's rating.
PFC uses a boost regulator which draws current continuously, not in pulses. When the transistor is on current flows from the mains into the inductor and ramps up a little. When it switches off it flows from the mains to the HV rail via the diode and falls a little. So it has some triangular ripple but is not discrete pulses. It should be a lot kinder to breaker contacts than a non-PFC supply.
Hello, Clive, here in Romania there is a trend for installing fuse separators(fuse holders for 38x10mm fuses, or 14x51mm) as a general "breaker"... Schneider does not require " backup fuse" as other mcb or rcbo does...
That pause and rapid closing before making connection when you try to close the breaker is intentional, it reduces arc when closing breaker on a short circuit. It is called fast close I think.
Hi sir I watched Jordan’s video and noted he intended to send you the device for your perusal . So I’m fascinated by your results . We as electricians fit these units day in day out . Taking little though as to how complex they are , and as you say in reality relatively cheap. Which begs the question, should they be more robust and more expensive? . And from your perspective would manufactures be better designing a device purely for this purpose, and not relying on the existing technology that is used in other parts of the industry. Thanks from an old retired electrician 😃👍
There’s a good case for making circuit breakers that fail out if the contacts overheat, and cannot be reset. Low melting point alloy perhaps? If the contact came away the actuator could swing past its usual position and disengage from the reset lever.
I'm well aware of this, I'm trying to find out why dimmer switches are derated for LED bulbs and I wondered if there was any common reason. I didn't suggest that LED bulbs have PFC circuits.
@@chrishartley1210 Sorry. LED fixtures do have switched mode power supplies which do, as Clive stated draw what power they do use as spikes. Dimmer switches are even more susceptible to damage from spikes since the dimming component is a semiconductor.
I wonder about my fridge if thats what caused my circuit breaker problems I discovered a few months ago. Its a fancy "inverter" unit against my wishes, so Im sure its doing PFC. In my case the contact inside the circuit breaker didnt burn as much as the contact where the breaker mates to the ?backplane? of the panel itself. Gouged it out pretty good. What dosent help is they installed too small of a panel so the panel is filled to the brim with tandem or quad breakers. I think the Oven, A/C Compressor and Electric heat are the only ones that escaped with standard size breakers. So theres two circuits worth of load on one contact.
100% agree, third harmonic. Some EVs with high power chargers, but only running at 7.4kW or less are particularly bad in this respect. Some Renault Zoe’s with 43kW chargers exhibit this issue. Same reason you need very high current diodes in a linear DC power supply.
@@Sixta16 no, I’m not is the charger but has a high third harmonic load that causes the problem. It only affects the high power Zoe chargers where the slicing angle is very small.
@@bigclivedotcom I suppose any contacting materials will always have some resistance be it high or low, a more arc resistant material may be what's required over a larger surface area? Or would that have the opposite effect? 🤔 When you look at a relay contact it is a specific metal attached to a copper strip, usually riveted on, and it is usually domed to reduce the arc? I'm assuming? When new they are almost polished in finish to what I would think creates a narrower, colder arc? Fascinating subject in its own right. It looked like this RCD didn't have any of those characteristics.
Why do I imagine a factory full of workers desperately trying to hold together a two sided spring loaded contraption spontaneously combusting at random inopportune moments??
AC will come out of the sense coil for the RCD, so the two diodes and two capacitors are going to be turning it into DC. Probably with one of those centre-tap full wave rectifiers. The tripping mechanism with the finely balanced magnetic field requires DC of the right polarity to trigger, and feeding it the wrong polarity would cause it to remain latched. Those are polarised capacitors after all. So I’m sceptical whether your reverse engineering is correct.
These videos keep reminding me I desperately need to do a tear down on one of the shitty MK RCBO's that go short circuit, I really need to know why they do it. I am going to have to set myself a time limit, that if I don't do a video I am going to have to send it to Clive
@@bigclivedotcom All 3 I have had go short circuit do so on the output side (so they trip themselves) then when you try to reset them, you are resetting into a hard short and you take out the house fuse. No faults were present on the downstream side each time this has happened. I'm surpised that I've never heard anyone else talk about this fault with MK RCBO's as it can't be just me
Well, I bet, Clive, you meanwhile saw the test resistor by yourself, but if not, look at the bottom of the device, right in the corner with the sense transformer. Just under the screw terminal is a quite big resistor standing "vertically" :-)
They are crap, £400 straight from the factory, I received a Type2 Rolec charger and it had loose copper strands in the bottom rattling around and loose ferrels from the terminals.. Use cheap Chinese parts with their Logos on..
I understand the pulsed current draw causing a problem. Many years ago in the UK there was a Philips TV called the G8. It had a half-wave thyristor power supply. Quoted 300 Watts so you would think just over 1 amp. Wrong. It was short duration spikes of 12.5A! I encountered several melted plugs, and 5 amp fuses didn't last long! 😃
Then there was itssuccessor, the G11 which would pick up Radio Norway International(6MHz in the Short Waveband via the not so well screened 6 MHz sound IF)
@@rowanNClangley oh yes the G11. Full-wave thyristor power supply. Lovely until the reservoir capacitor's rivets started arcing and falsely triggering the thyristors. HT up to over 300 volts, sending the EHT into orbit and cracking the neck of the CRT! Saw it many times
@@rowanNClangley one of those G11's blew up that way in a shop I was working in once. I was standing next to it. Tremendous bang Corona discharge from my hair and fingertips. Heaven only knows what the EHT went up to. At that point a lady came into the shop. "Ooh it smells like the beach in here it's lovely. What was that terrible bang just now?"! All I could wearily reply was (still shaking), don't ask! 😂😂
I think the cause of the failure is simply that charging an EV draws large current for an extended period of time. Other loads of similar current e.g. heating are intermittent so things have time to cool down.
Almost any EV will have Power Factor Correction for the simple reason that bad power factor causes current to effectively double for the same amount of power. It costs more to build in a heavier connector and internal wiring than just using a PFC module.
Watched the Video with Jordan removing this a few weeks back. Alway steered clear of Rolec because of reliability issues. Hence why I have a Zappi with the PEN fault detection.
Thanks Clive! One of your Patreon supporters sent me the link! Great video! Absolutely fascinating.
Good timing, I was just about to send you the link.
Rolec breakers are notorious, but it's usually the top-left Neutral that burns - plenty of reports on car forums about this
Do you know what kind of tests and QA manufacturers do for their MCBs, and RCBOs? My guess, is that this issue should have been detected by measuring voltage drop at 40A.
I had two (Home and Work) Rolec car chargers when we first got EV (5 years ago). Both burnt out, one distorted the outer case too and was no longer waterproof. Breakers changed under warranty but at considerable inconvenience/cost to the installer (and me somewhat until it was fixed).
The general concensus is to replace them with a Garo RCBO - RCBOGRB40
I did this with mine when mine blew & it's been fine ever since.
Although it did take 4 years for my Rolec one to burn out.
@@andywonline Not often I see Garo mentioned outside Scandinavia, but they dominate the market here for a reason :)
How much do these breakers cost? Can’t one install some better grade units from an industrial catalog? I’d expect a decent DIN rail branch circuit rated breaker (no RCD) like that to go for at least £100, although the best quality ones would be closer to £200 (I’m translating US prices and adding VAT). An RCD+breaker combo I would trust would be more like starting at £200. I’ve never had those fail, and have well over a thousand of them in the field.
@9:22 you can see the bypass resistor (right from the screwdriver). And a thin red wire then will do to the test button at the other side.
Yeah. I saw it there when he was looking for it.
Thanks Again BigClive. I believe you made this failure mode completely understandable to me. Pretty melty. Maybe not change contact itself but the flipping plastic capturing it. Another great Patron Video for us. Thank you Jordan also.
The main issue with EV charging is it's drawing a heavy load for an extended period of time.
I doubt most (any?) EV onboard chargers have poor power factor as that would cause problems on the network so I'd be highly surprised if the applicable standards don't specify a pretty good PF. One OBC I took apart definitely had power factor correction.
yeah, the main problem with EV chargers is EMC, not overcurrent spikes.
Yeah, any respectable design will have a small inductor between the PFC stage and the network to prevent the "spikyness" described in the video, and that results in a pretty darn good sine wave.
Some newer car chargers supply the main battery with pulsed DC to eliminate the need to do full PFC in the car charger - the Li-Ion battery doesn't mind if the charging current has a sine profile.
It seems odd that it would have an issue with a heavy load for extended periods given the loads of old GEC units was greater than current car points and I've never had issues with them.
More often it appears to be the on board dc conversion throwing issues back upstream. From personal experience I've had more customers with Telsa's have issues with the Relec points than Nissan Leaf and Renault Zoe owners. Not had any issues with the Zappi units yet though.
@@hugoboyce9648 Actually you would want to add a low-value capcitor after the bridge rectifier and before the APFC boost stage.
From the IR1155s APFC control ic app note:
_The purpose of the high-frequency capacitor is to supply the high-frequency component of the inductor current (the ripple component) via the shortest possible loop. This has the advantage of acting like an EMI filter, since it minimizes the high-frequency current requirement from the AC line. Typically a high-frequency, film type capacitor with low ESL and high-voltage rating (630V) is used._
_High-frequency input capacitor design is essentially a trade-off between:_
_· sizing it big enough to minimize the noise injected back into the AC line_
_· sizing it small enough to avoid line current zero-crossing distortion (flattening)_
12:50 You've instead drawn the very nice lady from Total Recall.
I was thinking Eccentrica Gallumbits myself...
The resistor is right in the corner of the unit in a tiny compartment on its own. Grey in colour, you can just see the end of it.
17:11 Clive's right thumb is covering the resistor.
Never knew about the "magnet thing". Really interesting (as usual), those breakers are pretty packed with components, and "a bit charred inside" may be an understatement!
Just needs a good cleaning and it'll buff out. 😁
Just a bit charred is his way of saying incinderated.
In an old data center (circa 1995), we had panels where overloading one circuit would trip the neighboring breakers as well. Such is the price of "fancy" magnetic breakers. I don't see many of those anymore.
Yeah, like the 'magnet thing' design. So the current in the coil doesn't have to develop enough magnetic field to actually pull in a solenoid armature or anything. Just enough to oppose / weaken the field of the permanent magnet.
Clive, as others have commented I think you have a few things wrong in this video. Power factor corrrection circuits do not draw large current spikes unless they are faulty. Their whole purpose in life is to draw a roughly sinusoidal current in phase with the mains voltage. The do this by using a high frequency switch mode boost converter to supply the main converter with a voltage high than the peak mains voltage and modulating the power they deliver to be proportiional to the mains voltage. The high frequency component of the input current is filtered out leaving a 50Hz sinusoidal current. Also the circuit at 15:50 couldn't possibly generate a dc voltage to drive the solenoid.
Thank you Clive, and Jordan.
"You can always skip ahead..."
You got a better chance of seeing God.
WHAT CAN I SAY...
It's just riveting content...
Well, that explains the odd visitor at 1am!
While one _could_ it's more interesting to watch Clive use nippers as pliers. (That rarely works for me.)
Excellent forensic work! I believe that many engineers underestimate the effect of the high frequency pulsing current on the contacts.
6:14 There's a clever mechanism that makes the contact snap in place to avoid arcing when the breaker is reset slowly.
Any such arcking will be low current.
@@millomweb Still.
@@millomweb not if the fault is still present
@@AngDavies The fault appears to be the contactor.
@@millomweb the contactor was engineered to deal with many faults, not just this one
17:00 18:14 resistor at the corner says hi
I kept wanting to point "its there- no.. you're touching it right now! aah"
@@mica4153 yep. It is a grey resistor surrounded by grey plastic, but still... he even kept saying it should be connected to the red wire, but didnt trace where it went, lol.
What I find incredibly interesting here is, all the incredibly thin wires, tiny sensing circuitry, low melting point plastics in the trip mechanism (all of these designed to be the weak point failure points) didn't fail. Nope, it was the beefy bigger current flow contacts that failed (from arc-ing because of uneven contact surfaces) and the heat resistant outer shell plastic that melted, causing more contact failure from plastic residue spitting on to the contacts, and eventually causing enough heat buildup to trip the bimetal strip microswitch. I wonder what would have happened if the melted plastic had glued the main switch contacts together more firmly instead?
Was waiting patiently for this one after I saw the other video.
Thank you, Clive! You videos are always both entertaining and educational! Greetings from Sweden!
3:47 How could I get bored by such riveting content?
I did my EV course recently. On it was a bloke who worked for rolec in the past. According to him: 'They buy a container load of the cheapest Chinese breakers/RCDs they can and print a Rolec logo on them."
Hehe, I also subscribe to Artisan Electrics. I'm a trained electrician from Germany and find it very interesting how things are done in other countries.
Thanks Clive, very interesting video. RUclips is such a great resource, I always learn something from the videos.
Finally the follow up or any follow up. Watching drain addict I'm always disappointed when there's something that needs to be followed up and it just ends
@6:19 "It's almost like it... before popping in." That's exactly what it does. It snaps closed fast at the last bit to minimize arcing. You should see high current, high voltage breakers doing it - it's... deafening!
He probably did, in his first job as a young apprentice electrician servicing steelworks.
15:11 - Reminds me of a gadget I got for Christmas as a child: Crdl (quote from the box: "It Rhymes with Fiddle.") It was a black plastic base with internal magnet, and a small pile of diamond-shaped metal bits you could, theoretically, make sculptures with.
I wonder if the plastic can fail in such a way that it locks the contacts closed? I wonder what the stats on this is.
I ALWAYS learn something new with Clive! Thanks for all the cool videos , Clive!! 👍👍😄😄
PS: That is one hell of a complicated breaker!
Clive, I am not sure you apply power factor issues appropriately here. Even with the blocky simple circuit the power factor will be pretty much perfect . The current is in phase with the voltage, all be it with a different waveform.
The problem with switched mode power supplies is that they reduce the size of the capacitor (to save space). This mean that to deliver constant power, they draw more current at low voltages (P=IV) and *only* smooth out between pulses, not half cycles of the supply.
A power factor corrected charger (as you mentioned) will correct for this.
Great content Clive. Very interesting.
I can't imagine how much time you spend making this content! It's great
Of note: there are two types of power factor: the usual kind, where current is out of sync with the voltage, and harmonic power factor, where they may be in sync, but the current has higher frequency components in it.
The power factor from the capacitive droppers is the second kind- that "pulsy" current wave can be represented as a sum of sine waves at multiples of 50Hz, but only the 50hz provides useful power, the rest just add extra current into the system causing various issues depending on the remainder upon division by 150
The contact tips used to be high quality silver and had a wiping action when they opened and closed to ensure a clean surface and in the case of DC rated contactors and breaker used a permanent magnet to help draw away and extinguish the arc over the arc shields and reduce spatter and grud forming on the contact surface. The newer devices seem to be moving down the path of cheap and nasty with material that tend to end up giving way to high resistance connections and failure, engineered obsolescent to promote further sales of more land fill. While recycling is the mantra way too much just become wasted resources ending up in landfill.
@12:53 Apparently you haven't seen "Total Recall". ;-)
LOL
I bet he *has* read Hitchhiker's Guide, though...
@@RedwoodRhiadra Heh
LOL! That was exactly what I thought as he was drawing and commenting.
I was thinking of getting a Rolec charger installed on my Garage since my new electric car is due in a few months. Everyone on the EV forums basically said "no" and then I was linked this video (plus many, many pictures of exploded Rolecs). I don't exactly feel secure connecting a giant lithium bomb to one of these now...
High frequencies, perhaps start getting skin effects where the core of the conductor carries less of the current than the surface. Not so much a problem with small wires at kilohertz but as things go faster ... Also the magnetic fields from the current pulses may be creating forces which make the contacts resonate and start bouncing...
We have so many bad breakers in Canada from Bulldog/ITE, Federal Pioneer, and Sylvania. So many prone to blistering and failing closed and just no longer closing. Some burning the buss bars in the panels
Are the breakers being used as a disconnect instead of a switch designed for disconnecting under load? One of our buildings had the lights only connected to a breaker instead of light switches and the breakers would fail often until proper switches were installed.
I was thinking along similar lines: has the EV-user/owner been using the RCBO to interupt charging and therefore the contacts are breaking 7kW once or twice (maybe more) every day - NOT what they are designed for...
thanks to clive, jordan and mike - my tiny brain has been fed a bit. I wonder if Rolec have an opinion or pay clive a consult fee.
so if i glue a magnet to the door that presumably covers this, the breaker will trip every time someone closes the door? and even changing the breaker won't help?
Id be interested to know what Electric car this was charging in theory no EV should draw more than 32 amps AC as the cars on broad charger doesn't allow them to some EVs are only 16amps. However the Renault zoe is able on the Q motor to take much higher loads on a 3 phase supply it will happily go to 43kw. I've seen a zoe on a single phase draw over 7.6kw on some chargers for breif moments. Am currently reviewing EVERY EV charger in the UK Rolec still haven't sent me there unit for testing....
You mentioned that a bit of plastic which had melted had made resetting difficult, I wonder if a combination of poor connectivity of high current creating heat deforms the plastic making the connection worse compounding the problem until failure..
9:00 That little coil with magnetic core is very similar to one I discovered in a professional magic coin trick.
How about a line or load reactor typically used in line with 3 phase variable frequency drives. Would one help to smooth out the current at the breaker?
A few years ago I built a small device that I would use to annoy my parents (I am only 18) by remotely tripping the master circuit breaker. It consisted of a battery, electromagnet, MOSFET, and ESP8266. The ESP8266 (WiFi enabled microcontroller) would drive the MOSFET via a BJT. The MOSFET controlled power to the electromagnet, which when powered would cause the breaker to trip. I hid the device behind the panel where it could not be seen and would activate it remotely.
Had a look at the AE video. One of the things he did was fit a piece of plastic pipe to a close by water tap so the tap was isolated from the house earthing system. As a sparky, he forgot to connect the tap to a supply of plastic water too. Had he done an insulation test on the tap, he'd have realised the other error.
In the USA we have to use arc fault breaker’s in bedroom circuits. Are they similar to anything you guys use? My understanding is that they are different from GFCI breakers.
Would a C or D grade breaker work better with EV chargers? I assume they may have bigger contacts due to the higher loads they can withstand
"They're a bit sloppy so they can just......mate" - Big Clive 2020
Yeah because of that research I now look at magnets like they are electricity since you are such an educated electrician I figured just telling you this would be enough to give you the Revelation you need
Where did you get that big rod magnet? I've been wanting to demonstrate what happens when you drop one of those through a copper pipe.
eBay. They have a wide selection.
on many EV cars you can set the current draw, but like with most things people tend not to RTFM, as it is the vehicle that does the conversion to DC and charging of the battery, the box on the wall tends to just turn the power on and off from a signal from the vehicle. from the looks of it, the load limit on the vehicle is set just to a whisker of the overload limit.
Clive I like your videos and I was a research scientist working on a brand new electric motor I can tell you exactly how it functions and let me tell you there is no need for rectifier
I bet you'd love to teardown one of the new AFDD's, some of which have fully fledged microprocessors in them that would shame the first IBM compatible PC that I had!
the input of a high power device like a car charger should not look as spiky as you depict it, without those crazy 60 amp spikes.
It should basically just be a fair bit of ripple, while the current curve largely follows what you'd expect of a purely resistive load.
My two favourite channels do a colab! This is like Christmas!
What's wrong with Schneider, ABB, Eaton, Hager, etc? Who is Rolec?
What's the best contactor? I'm thinking a blade style one.
good show. what would that thing look like in the fifties?
Thanks for the explanation about the spikey current load - this explains why my microwave (which has a switch-mode PSU) makes a strange noise when my EV is charging.
Ps. Apparently the Renault Zoe uses the motor coil as the inductor in the charging circuit to save weight. 🤓
I am having a tethered 7.2KW Rolec installed but I will be dialling down my EV's internal charge rate controller to receive a maximum of 12 amps. The charge rate I choose will broadly match production from my solar PV system on the day. Would such a light load over a maximum 6 hours (two or three times a week) extend the life of the circuit-breaker, in your experience?
A lower current does take a lot of strain off components like this.
This is a really compact device actually. Nice engineering. It is a single pole breaker tho, so be aware of that.
I think the issue was poor manufacturing of the brass part. They are probably cast, and then roughly machined. If there was a burr on the edge, and not smooth, the burr would prevent making the full contact of the two parts. Good QA with passing 40A and checking the voltage drop, to measure resistance, would detect this. But I guess, they are skimping on that.
Intersting, we have two Rolec wall chargers, one has failed within 3 years, I replaced the breaker with a different make.
I enjoy your videos so much!
In my opinion, this fuse was burnt due to long time over current Condition.
Most people don't expect what ther actual current draw really is. If this would only have used with a car charger - in Germany the Current Limit for that is about 10 to 16A @ 230V. I think this kind of load should not result in a picture like we see here.
Most of the time, the fuse for the garage is also used for the cellar.
So if there is a washing machine (10A), electric heater(16A), some hobby or garden related objects (8A) and finally the car at 16A we get a total current of 50A.
In this unlucky situation, the OverCurrentProtection might not trip, even after hours. But the electrical overload will lead to early failures like this.
Of course it makes sense to buy a reliable Circuit Breaker, but if you use it wrong, only luck can tell how long this works properly.
Sorry Clive I believe your understanding of the current drawn on a PF corrected supply is not correct, the current spikes on the old style supply are huge to charge the capacitor when the mains is above the capacitor voltage. The whole point of the PFC types is to spread the current pulses across the whole period.
I would personally guess that that breaker was running at or near it's rating.
PFC uses a boost regulator which draws current continuously, not in pulses. When the transistor is on current flows from the mains into the inductor and ramps up a little. When it switches off it flows from the mains to the HV rail via the diode and falls a little. So it has some triangular ripple but is not discrete pulses. It should be a lot kinder to breaker contacts than a non-PFC supply.
PFC does not have to use a boost configuration. Plenty other PFC-aware topologies do exist and are being used.
Thanks Clive, now I am worried about installing a car charger!
They're generally safe.
Hello, Clive, here in Romania there is a trend for installing fuse separators(fuse holders for 38x10mm fuses, or 14x51mm) as a general "breaker"...
Schneider does not require " backup fuse" as other mcb or rcbo does...
That pause and rapid closing before making connection when you try to close the breaker is intentional, it reduces arc when closing breaker on a short circuit. It is called fast close I think.
Hi sir I watched Jordan’s video and noted he intended to send you the device for your perusal . So I’m fascinated by your results . We as electricians fit these units day in day out . Taking little though as to how complex they are , and as you say in reality relatively cheap. Which begs the question, should they be more robust and more expensive? . And from your perspective would manufactures be better designing a device purely for this purpose, and not relying on the existing technology that is used in other parts of the industry. Thanks from an old retired electrician 😃👍
I wish they would make them better quality even at greater expense.
So the bi-metallic strip detects overloads and the magnetic coil detects dead-shorts...
There’s a good case for making circuit breakers that fail out if the contacts overheat, and cannot be reset. Low melting point alloy perhaps? If the contact came away the actuator could swing past its usual position and disengage from the reset lever.
Yay, was waiting for this one 😁👍 charred safety devices always stir my curiosity..
Is there any relationship between your idea about overload caused by PFC and the derating of dimmer switches when using LED bulbs?
LED lamps rarely contain PFC.
@@johndododoe1411 True, I think there is confusion between PFC and switched mode power supplies, which LED bulbs certainly have.
I'm well aware of this, I'm trying to find out why dimmer switches are derated for LED bulbs and I wondered if there was any common reason. I didn't suggest that LED bulbs have PFC circuits.
@@chrishartley1210 Sorry.
LED fixtures do have switched mode power supplies which do, as Clive stated draw what power they do use as spikes. Dimmer switches are even more susceptible to damage from spikes since the dimming component is a semiconductor.
The inrush current to capacitors and terrible power factor of capacitive dropper based lamps is probably the main issue.
is that a resistor near the transformer in a little hole
Yes it was.
I wonder about my fridge if thats what caused my circuit breaker problems I discovered a few months ago. Its a fancy "inverter" unit against my wishes, so Im sure its doing PFC. In my case the contact inside the circuit breaker didnt burn as much as the contact where the breaker mates to the ?backplane? of the panel itself. Gouged it out pretty good. What dosent help is they installed too small of a panel so the panel is filled to the brim with tandem or quad breakers. I think the Oven, A/C Compressor and Electric heat are the only ones that escaped with standard size breakers. So theres two circuits worth of load on one contact.
They are just the tiniest rube goldberg machines
These are not exactly cheap and often the service entrance is out in the elements causing them to fail due to internal rusting.
100% agree, third harmonic. Some EVs with high power chargers, but only running at 7.4kW or less are particularly bad in this respect. Some Renault Zoe’s with 43kW chargers exhibit this issue.
Same reason you need very high current diodes in a linear DC power supply.
This is a single phase charger. You are mix and matching stuff together.
@@Sixta16 no, I’m not is the charger but has a high third harmonic load that causes the problem. It only affects the high power Zoe chargers where the slicing angle is very small.
Is your thought that pulsing is causing contact arcing?
My thought is that any contact resistance results in much greater risk of arcing.
@@bigclivedotcom I suppose any contacting materials will always have some resistance be it high or low, a more arc resistant material may be what's required over a larger surface area? Or would that have the opposite effect? 🤔 When you look at a relay contact it is a specific metal attached to a copper strip, usually riveted on, and it is usually domed to reduce the arc? I'm assuming? When new they are almost polished in finish to what I would think creates a narrower, colder arc? Fascinating subject in its own right. It looked like this RCD didn't have any of those characteristics.
"You can always skip ahead if you don't want to see me remove the rivets" -- nah, the action is riveting, clive!
Why do I imagine a factory full of workers desperately trying to hold together a two sided spring loaded contraption spontaneously combusting at random inopportune moments??
The same happened to my Rolec. They should recall these!
AC will come out of the sense coil for the RCD, so the two diodes and two capacitors are going to be turning it into DC. Probably with one of those centre-tap full wave rectifiers. The tripping mechanism with the finely balanced magnetic field requires DC of the right polarity to trigger, and feeding it the wrong polarity would cause it to remain latched. Those are polarised capacitors after all.
So I’m sceptical whether your reverse engineering is correct.
The diodes only cap the voltage. The coil will have AC coupled to it, but can potentially release on the desired half wave.
These videos keep reminding me I desperately need to do a tear down on one of the shitty MK RCBO's that go short circuit, I really need to know why they do it.
I am going to have to set myself a time limit, that if I don't do a video I am going to have to send it to Clive
The RCD circuitry often latches, if it can't trip the breaker it may be causing catastrophic circuitry failure.
@@bigclivedotcom All 3 I have had go short circuit do so on the output side (so they trip themselves) then when you try to reset them, you are resetting into a hard short and you take out the house fuse. No faults were present on the downstream side each time this has happened. I'm surpised that I've never heard anyone else talk about this fault with MK RCBO's as it can't be just me
did RUclips let the work experience kid near the function key that shut down the network?
(I think my dad did that to VicRoads)
Will a Joule Thief work for 3 batteries LEDs?
I can't skip forward: It's Riveting!
Well, I bet, Clive, you meanwhile saw the test resistor by yourself, but if not, look at the bottom of the device, right in the corner with the sense transformer. Just under the screw terminal is a quite big resistor standing "vertically" :-)
I fully expected, "I'm not an expert at opening circuit breakers, but I play one on RUclips".
😂🤣😂
These Rcbo,s are band here.
They have to be type F or type B for CCS.
They are crap, £400 straight from the factory, I received a Type2 Rolec charger and it had loose copper strands in the bottom rattling around and loose ferrels from the terminals.. Use cheap Chinese parts with their Logos on..
I understand the pulsed current draw causing a problem. Many years ago in the UK there was a Philips TV called the G8. It had a half-wave thyristor power supply. Quoted 300 Watts so you would think just over 1 amp. Wrong. It was short duration spikes of 12.5A! I encountered several melted plugs, and 5 amp fuses didn't last long! 😃
Then there was itssuccessor, the G11 which would pick up Radio Norway International(6MHz in the Short Waveband via the not so well screened 6 MHz sound IF)
@@rowanNClangley oh yes the G11. Full-wave thyristor power supply. Lovely until the reservoir capacitor's rivets started arcing and falsely triggering the thyristors. HT up to over 300 volts, sending the EHT into orbit and cracking the neck of the CRT! Saw it many times
@@rowanNClangley one of those G11's blew up that way in a shop I was working in once. I was standing next to it. Tremendous bang Corona discharge from my hair and fingertips. Heaven only knows what the EHT went up to. At that point a lady came into the shop. "Ooh it smells like the beach in here it's lovely. What was that terrible bang just now?"! All I could wearily reply was (still shaking), don't ask! 😂😂
This video was riveting.
Such tiny little wee parts that protect us from the dangers of electricity.
I missed what the capacitors are for? Ah got it now, thanks Clive
I think the cause of the failure is simply that charging an EV draws large current for an extended period of time. Other loads of similar current e.g. heating are intermittent so things have time to cool down.
I've got some ancient zinsco breakers that you can compare to these modern failed breakers.
that was toasty `interesting to see the insides. 👍👍
Almost any EV will have Power Factor Correction for the simple reason that bad power factor causes current to effectively double for the same amount of power. It costs more to build in a heavier connector and internal wiring than just using a PFC module.
Not that I doubt your circuit diagram in the slightest, but are you sure it’s not a voltage doubler?
The diodes are in inverse parallel. Just a bidirectional voltage clamp.
Watched the Video with Jordan removing this a few weeks back.
Alway steered clear of Rolec because of reliability issues.
Hence why I have a Zappi with the PEN fault detection.
12:52 For some reason I'm reminded of that mutant chick in the original Total Recall.