Why Circuit Breakers DON'T Protect People (electric shocks)

[@EngineeringMindset]

*This free video took weeks to make!* if it helped you and you'd like to thank or support Paul's efforts, link below: PayPal: www.paypal.me/TheEngineerinMindset Patreon: www.patreon.com/theengineeringmindset Channel membership: kzbin.info/door/k0fGHsCEzGig-rSzkfCjMwjoin

[@windowsgaming-dn9qx]

how many times did you zap yourself

[@Win11FTW]

Yeah it true

[@BeaulieuTodd]

The video literally stated just that, right from very start.

[@philpeko1796]

Congratulations for achieving such a useful, educating, yet understandable channel, and thank you for your work. Loing time s subscriber, I wanted to thank you using some of your Amazon affiliates Tools links, but almost half of them are broken, or products are unavailable. May I know when you could update them, and keep us posted? Peace & Prosper! ❤ & 🖖

[@michaelm6597]

I knew immediately where you were going with the name of the video and was well done. This gave extremely good insight to how breakers work and I personally loved the bits showing how they trigger with the side removed (especially as I would never remove the side of one myself)

[@xTerminatorAndy]

This is a gold standard for showing how breakers work. Very pleased with that

[@thomasvlaskampiii6850]

The fact that you replied to my comment from 3 years ago and gave a link to this video was a nice gesture. I appreciate it

[@EngineeringMindset]

It took a while to make, but I hope you enjoy the video

[@2Pzp]

@@EngineeringMindset Not every hero wears a cape

[@Ryuken2721]

great stuff takes time.

[@tanithrosenbaum]

@@2Pzp Engineering heroes wear shirts, ties, jeans and tennis shoes :)

[@tuckkeongho]

This is about the best video explaining how a MCB works. Well done.

[@AtAGlimpse_UB]

Dude, the transitions are so freaking mind boggling! Great Job Paul!

[@EngineeringMindset]

Thank you, glad you liked the hard work

[@Tishers]

As an electrical engineer I have repeatedly attempted to explain circuit breaker operation and curves to technicians and electricians. No matter how extensive (or simplistic) I make my explanation it ends up with them offering up a sceptical look and them just accepting the answer without really gaining an understanding. This is an excellent video; I shall share this as the teaching video for breakers. Thanks so much for putting the effort in to creating it.

[@johnchestnut5340]

You interact with the wrong technicians. I started in engineering and moved to technology. I ran out of money before finishing. I assure you that this is covered in technology classes. Electricians are at least introduced to this information. Perhaps the teachers are more knowledgeable than competent?

[@bladeoflucatiel]

its not rocket science, you should start by showing them actual manufacturers datasheets (hager, abb, siemens) instead of generic theoretical curves and going item by item and what they mean. Buy a couple of diferent types of breakers and pass they around during class. You should also mention its more about the country regulations than actual specs requirements, for instance in the UK they use type B breaker with 6000amps breaking capacity, while in europe its C type 3000amps.

[@GregoVal]

I don't know where these electricians came from. But any certified electrical technician should know something as basic as how electrical protections work.

[@laus9953]

​​@@bladeoflucatielno, he shouldn't - his presentation is fine the way it is ! your country specs statement is wrong.

[@Andrew-pw6zu]

Don't blame the student. Blame the teacher

[@JoaoVictor-hz4rm]

I'm loving this more live-action kind of videos

[@EngineeringMindset]

Glad to hear, will be doing more of them where possible

[@JoaoVictor-hz4rm]

​@EngineeringMindset glad to hear, today's videos are becoming more and more made without love or even with AI in some extent, you're putting more and more of your personality in your content

[@thawzinkhant1759]

I concur

[@krashd]

It still astounds that just 30 years ago my house had no circuit breakers, we still had the good old fashioned "fuse box", there was no consumer units or MCBs or anything shiny and white with inspection labels on it as we didn't get any of that until around 1994 - no, instead we still had an ugly brown box twice the size of a CU that looked like it was made of bakolite, and shoved in to the front was a dozen big ceramic fuses the size and shape of bourbon biscuits. I remember any time something blew my dad would remove the appropriate fuse cartridge, pull out a snapped/melted chunk of wire and then, spool a fresh piece of wire to it before plugging it back in. I'm glad that now the house is mine I don't have to rely on anything so archaic to keep fires at bay.

[@gamecubeplayer]

why didn't the uk use screw in fuses like europe & america?

[@ArmChairPlum]

Fuses do what they are supposed to as well, just an inconvenience to have to replace - especially it's the fuse wire kind. Tolerances would also be an issue. At least with these being resetable makes it a lot more friendly. Great for if someone tried to use the electric jug while someone had a sandwich in the microwave.

[@jhanthony2]

Those circuit-breaker graphs are great! I learned a lot from this.

[@altuber99_athlete]

They are called trip curves.

[@nuigiengtien]

@@altuber99_athlete Verry good

[@gg-gn3re]

@13:00 good to add that the arc chamber is "up" aka away from gravity. The arc travels up as heat rises due to gravity. If you install breakers upside down you can actually get good arcs to melt internals instead. It's a fun exercise lol awesome video as always

[@FilinMXr]

I was just wondering why arc moves upward, thank you

[@thebamplayer]

Also the resulting magnetic field moves the arc away.

[@ImieNazwiskoOK]

Seems like circuit breakers for the ISS might be bit more tricky(aside from a lot of them having to work on DC voltage)

[@gg-gn3re]

@@ImieNazwiskoOK Yea even DC breakers on earth are designed differently/specific to DC. Getting the arc killed on DC is much more difficult as well I wonder how the space station ones look but the magnetic field up there probably takes priority thus it may not need much of a design difference. Down on earth it's so weak that the heat matters more and heat rises due to gravity

[@Delibro]

@@ImieNazwiskoOK Thinking outside the box, no matter how relevant. I like this :D

[@zeux5583]

The charts are extremely well explained. Im doing an apprenticeship to becoming an electrician right now and none of the teachers at trade school managed to explain them as clearly as you have done.

[@bjornroesbeke]

Pointing out what the "3000/4500/6000/10000" is for would fit this video well. All too often i hear people (even colleagues) say "it can handle 10000 volts" and they refuse to accept that it means Icu or maximum breakable short circuit current.

[@EngineeringMindset]

Good point, If the video is popular I can follow up with some additional info.

[@arjun-vh7np]

You are the only electrical engineer i have noticed explaining the breaker selection chart clearly and neatly....do more videos brother keep it up....

[@rahul2000]

bro have one of the best engineering channels i have learnt a lot from you despite being a mechanical engineer myself about electrical as i also had a specializing in automation

[@HimalayanYeti]

This is amazing!! The depth and simplicity of the explanation is just brilliant!!

[@tedchirvasiu]

.org

[@allangibson8494]

MCB’s can be safely mixed because they are designed to a common mechanical and electrical standard. Different manufacturers only becomes an issue if a distribution comb is used but that can even be an issue even with in a specific brand. The leading letter refers to the trip curve which goes beyond B, C and D - “A” being fastest and “F” being slowest (and usually used for variable speed motor circuits (and occasionally switch mode power supplies with high inrush currents). C curve breakers are the most common in domestic use. Direct On Line started motors typically draw seven times the running current during start. Hard Start Switch Mode Power Supplies draw their full output load current during starting - so a 5V 1000A supply will draw 1000A for the first fraction of a cycle until the output reaches 5V - so from a 240V supply 240kW (and having tripped a gas fired power station offline by turning on a computer system, this could happen (steady state the system drew 1kW - the power supplies were oversized and redundant (2off)).

[@themohaa2]

The only problem with this is that you will void any potential warranty the manufacturers give you, as it wasn’t used as they intended. Also, you cannot use that manufacturers electrical data/certification as this was only done based on their own parts. So if there was a house fire and they find out you have mixed breakers, etc, there’s no come back. Also on odd occasions the breakers just won’t physically fit in each other’s boards when the front plate is attached.

[@allangibson8494]

@@themohaa2 Mixed breakers are legal if installed correctly. If they don’t fit the manufacturer is selling non standards compliant equipment. Thats what standards are for - to ensure interoperability and interchangeability. BTW - my home switch board has five different manufacturers breakers installed, no problems because they are signed off by an electrical inspector. I have however had issues with incompetent electricians not tightening screws repeatedly.

[@laus9953]

"C" - type MCBs are most UNcommon in domestic installations.

[@allangibson8494]

@@laus9953 Which will come as a surprise to every electrician I have worked with - every house I have lived in was fitted with “C” curve breakers (including the ones on the solar panels). I’ve used “D” curve breakers on switch-mode power supplies in special cases and “A” curve on thyristor controlled heaters (to protect the thyristors). RCD breakers are a design requirement where I work too on all power circuits.

[@inkprod]

@@allangibson8494 Different countries have different 'standards' in that regard. Where I live practically all residential breakers are B-type (B16). I've only ever used C-types in commercial buildings when the circuit was explicitly used for computer equipment. If I recall the local norms correctly a D16 would not even be allowed in the average residential building due to not having guaranteed selectivity with the C25 protected incoming supply. Mixing vendors is at least totally fine here. Although the majority of newly installed breaker panels use vendor-specific busboards instead of bus-bars. So you generally only see brand difference in RCBO's that are installed later for things like solar.

[@zentrobi1548]

As en electrician, i just wanna confirm that this is proberbly the best explained video of a Circuit Breaker that i have ever seen. will definately be showing this next time an apprentice asks or anyone else for that matter.

[@TheEulerID]

The title is a bit misleading. True, MCBs do not protect people from fatal electric shocks. However, they do protect people from electrical fires due to overloads and, statistically speaking, electrical fires have been a much killer of people than electric shocks (particularly in the USA I should add, partly because of the way they build houses). To say that it is just there to protect property is simply not the case. Also, some MCBs are twin pole, although that's more an industrial and European domestic thing (at least in some countries). However, excellent job at explaining how MCBs work, and especially the dual-mode switching and why it's done that way. I note, there is still no mention of RCBOs. Those dual RCD consumer units are, thankfully, rapidly being confined to history and many electricians will no longer quote for split RCD CUs, and I'm a bit surprised that the regulations still allow them. Of course, then we come onto a far more contentious point, which as AFDDs.

[@EngineeringMindset]

Glad you enjoyed the video, note that RCD, RCBO etc will be covered in detail in dedicated videos. You have some good points but I will also add, and I'm sure you're already aware, but the MCB will only prevent (hopefully) a fire occurring from an overloaded cable, for example fixed wiring in the wall. But, most fires in homes start from faulty appliances. For example, if the decorative casing on a toaster catches fire, the MCB won't trip, it will happily keep providing power and heat to the fire until the entire house is ablaze. It will only trip when it detects a short or overload from something melting and creating a low resistance path. However, if someone drives a nail through the line and neutral when hanging a picture frame, it will detect this and cut the power, otherwise the nail would start glowing red and cause a fire. So it will only prevent certain fires. It won't prevent electric shocks, which I think most people believe is the case.

[@muulsh5341]

I was wondering what is the difference between single and twin pole ? In my breaker panel (in France) everything is a c type twin pole and I heard from a video by a french electrician that single pole was used before but it's no longer the case and less safe

[@S-mz2my]

single pole is for the live wire of a unique circuit -double or twin pole is FOR THE same circuit protection of the neutral wire @@muulsh5341

[@yourfaceisonfire]

I’m an electrotechnology lecturer, we teach our students the same thing by starting with the “breakers protect cable, RCDs protect people” in service of making the distinction between their designed purpose.

[@shaynegadsden]

Yeah that is a bad take it clearly points out how breakers works and fires are a secondary issue, that while performing their main function may reduce the chances of a fire they offer no protection against them

[@somedude4805]

They’re not meant to protect people, they’re meant to protect circuits. That’s why they’re called “circuit breakers” and not “people protectors”.

[@leeroyjenkins0]

They're meant to bag air, not to protect people. That's why they're called "air bags" not "people protectors" Filling the bag with air is a means to protect people. So could be breaking the circuit. Logic doesn't seem to hold up.

[@icyboyy6177]

@@leeroyjenkins0we should call every thing that protects people: “people protector”. Helmet? People protector. Epinephrine pen? People protector!

[@m4pplethorpegrey]

@@leeroyjenkins0no. they are not designed to protect people. circuit breakers, more properly known as overcurrent protection devices (OCPD) stop the flow of electricity in the event of an overcurrent to stop the wires from heating up. its to protect the insulation of the wires, not people.

[@JPK1337]

he's right tho.. circuit breakers are supposed to save the circuits inside the walls from getting destroyed. they are not for safety. that's what an rcd is for. ​@@leeroyjenkins0

[@idonjohnson6999]

So you could say they break people.

[@theavchap]

The clearest and simplest demonstration and explanation of how this works. Excellent work!

[@paulswearingen4395]

Great explanation and demonstration of the operation of a thermal magnetic breaker. However, I think it’s worth mentioning that circuit breakers do protect persons from electric shock - with proper grounding and bonding practices. The most likely scenario for a person to come into contact with an energized conductor is if said conductor has inadvertently touched a conductive casing that is not meant to be energized. When a person touches that casing their body is the current path for the fault (for any electrical system that uses earth as neutral). As you pointed out, fault current through a human body may be too low to trip the breaker and you end up being an unwilling conductor for much too long. To solve this issue, electrical systems are required to be properly grounded and bonded. This means that when metal casings (or other non current carrying conductors) are bonded to a conductive grounding system and become energized, the fault will now travel with low resistance through the grounding system, produce high current, and trip the associated breaker; thus preventing an electric shock. I really appreciate your content and just want to add some clarity to your title.

[@MaxPowerElectric]

A good point that I was going to mention as well. Grounding/bonding is obviously very widely misunderstood topic. As an apprentice electrician I even hear many of my instructors repeat the claim that "OCPDs prevent fires, GFCIs prevent shocks" which is true of course, but it fails to capture the purpose of bonding all metal parts in or near electrical systems together--the short circuit protection offered by fuses and breakers also serves the dual purpose of quickly removing hazardous voltages between exposed conductive surfaces during fault conditions, limiting the duration of a possible shock and the potential for serious injury--again illustrated by the time-current curves for these devices

[@gastonvale8172]

0:28 A good clarification is that the resistance reading of 300KOhms is due to the skin, which has a very high resistance. However, the internal resistance of the body is considerably less than 1000 ohms. Therefore, having wet hands or piercing an electrified wire under the skin can give you an electric shock that would not have occurred under other conditions. The capacitance created by the skin and the sole of the shoes can cause a shock under certain conditions too, such as touching an electrical element charged with high static voltage.

[@charlotteice5704]

I already knew this as it's a part of my job, you did an amazing job explaining! One thing I want to emphasize, especially for anyone using this video to study for an exam: the curves show at which current the breaker *can* trip, so it's not that a B breaker *will* trip from 3x rated current onwards, it *can* trip at 3-5x rated current and it *will* trip from 5x rated current to the maximum current it can break. So if you have an exam for this coming up and the question is "with V=230V and R=1O, will a B16A breaker definitely trip?", don't look at if the current exceeds 3x the rated current, look at if it exceeds 5x the rated current. In this case, it would take just 80A for the breaker to definitively trip, so we're golden with a short circuit current of 230A. But if you have a C32A breaker for lighting circuits (quite common in my field, event technology), it takes 320A for the breaker to definitively trip so a resistance of 1O is too high. If you thought of this calculation as "it takes 5x rated current for the breaker to trip so my short circuit current needs to exceed 160A", you would miss that problem which can become a costly and potentially deadly mistake. " *can* trip" vs " *will* trip" is a vital distinction here.

[@Frohicky1]

Slight pedantry warning. At 1:58, I think most cables are rated to a max temp, not a current. The temp depends on current, bundling, conduits, etc.

[@gamecubeplayer]

for example a 1.5mm² cable can easily handle 10a inside a wall but 16a outside a wall

[@Sirius-0007]

The level of content is just impressive. The pace in the video absolutely matches my learning pace, not too slow or fast, just perfect. I wish there were more creators in every field like you. Thanks for the amazing content man.

[@walterbrown8694]

Circuit breakers and fuses are not designed nor intended to protect people. Their purpose is to protect the electrical power system - generators/distribution/transformers and other electrical equipment from damage that could be caused by overcurrent or a "short circuit" fault.

[@JackCobalt]

I'm glad you said qualified and competent at 4:20, because I've seen a lot of people who are competent who think they're qualified, and people who are qualified but aren't quite competent 😂😂

[@LigmaBaldrich]

me who thinks i know what im doing (EE undergrad, NOT a qualified electrician)

[@Vodhr]

Back when I worked as one. I've seen some who were neither qualified, nor competent...

[@ArmChairPlum]

It doesn't help that in some countries, you are allowed to do basic electrical work yourself. Eg swapping a light fixture or plug socket. It potentially opens you up to putting it back incorrectly or making the decision to leave power on at the breaker and use the light switch to isolate the light.

[@MaskedDeath_]

@@ArmChairPlum In my country, you can get a cert to work with relatively high voltages without much hassle. It's pretty much a joke, as long as you know a fork doesn't belong in an outlet you'll get the certification.

[@__u__9464]

This was easily the best video I've ever seen on this topic in my whole life. Top tier quality right here

[@EvlNinjadude]

The only thing this is missing is to tie it more firmly to the things that DO protect people - the gfci (which was mentioned, but no video directly linked at the timestamp) and the funny green-yellow wire that's meant to take dangerous voltages and turn them into a current high enough to trip a breaker. Aside from that I have zero complaints. A meticulous and technical but extremely approachable dissection of a device everyone has probably glanced at once in their lives! It's a great video!

[@luispereira3]

Love the new format and the face behind the hard work! Thank you Paul for sharing the knowledge with the world, I've learnt so much from your videos!

[@Felipe_Nogueira]

The best class about circuit breakers I'd seen!! Congratulations for the content!

[@melliflousbufo]

Utterly brilliant description - thanks so much for taking the time to put this together!

[@Jimbobbinson]

Its wild how much engineering and thoughts have gone into these circut breakers. Well explained, easy to digest.

That's why we use 30 mA differential breakers in Europe.

[@zeux5583]

Also called RCDs, or Residual Current Protective Devices

[@mariustv927]

I'm an electrician and pretty much knew this stuff already. But you explained it so incredibly well and entertaining that I just had to watch the whole thing. Thank you!

[@skysurferuk]

A clear, concise explanation of these magical devices. Awesome, & many thanks for your work. 👍

[@datadrivendave]

My dad asked me just last week how breakers work. I knew there was a bimetallic strip, and was fairly sure there was also a solenoid. But this added some bits to my knowledge that were missing. Great video!

[@wernerviehhauser94]

Of course they don't. In German, circuit breakers are called "Leitungsschutzschalter", meaning "wire protection switch". And I love your "qualified AND competent". Already met too many qualified but incompetent....

[@Taokyle]

average german word length: (thx for the info tho lol)

[@rolandrohde]

​@@Taokyle Which is why we usually refer to them as "LS" instead...😉 There is also "FI" (which is the RCD essentially) and FILS which is a combination of both that is sometimes used.

[@Ghou1Lord]

This must be the best video available explaining breakers.

[@unyu-cyberstorm64]

101 reason why you need a GFCI

[@razsegev6415]

Rcd and GFCI is the same, only the scale and tripping current are different

[@unyu-cyberstorm64]

@@razsegev6415ah yes

[@unyu-cyberstorm64]

@@razsegev6415can they be used together?

[@razsegev6415]

@@unyu-cyberstorm64 probably. I made the first comment because Rcd was mentioned in the video.

[@unyu-cyberstorm64]

@@razsegev6415 They're the same thing. The point is tho, Circuit Breakers and Fuses protect property, GFCI/RCD/RCCB protect _people_ for added protection you could also install an AFCI or Arc Fault Circuit interrupter. They protect from Arc Faults.

[@Stelios.Posantzis]

This is a great explanation of the inner workings of a circuit breaker. Excellent work! There are, however, still questions left unanswered, mainly: a) at 11:40: Why does the piston always move downwards even if the current may be passing through the coil in either direction? There is no diode element in the circuit breaker. b) at 12:54: Why does the electric arc move from the narrower gap section to the wider gap section? Surely, the arc is easier to maintain when the gap between two electrodes is shorter. c) at 12:49: Why is the double copper electrode needed? Is the metal vaporized by the arc temperature or is the double thickness needed to better dissipate the heat generated by the arc?

[@Kavyatej]

the explanation to all of them are short, you can look them up!, but if he included it in the vid, it would have gotten a bit too "beginnery" or long

[@ajitjalady]

An RCCB will protect people. MCB is meant to protect short circuits.

[@ambassadorkees]

As an ABB Technical specialist, I give you props for a good explanation. Only 14:08 "Will trip within this zone" can be understood wrong, it is "Somewhere within or beyond this zone". You do explain it later correctly, but I usually point out the operation tolerance differently. You did include our green and blue competitors, why not the red brand?

[@smarteth4342]

I really love your videos. you made me more attached to the electrical concepts. thank you so much with much respect.😍😍

[@EngineeringMindset]

Glad you like them!

[@garza1367]

This page is remarkable, I watch all the videos. The illustrations coupled with explanation is amazing. I’m a master electrician (yes I know it’s just a title and just means I’m a good test taker) and I continue to learn.

[@nuigiengtien]

Study, learn more, learn forever

[@HabboBoembery]

Nice video bro, appreciate the content

[@EngineeringMindset]

Thank you

[@pcfreak1992]

This video has one of the best animations I have ever seen in an engineering video, good job! 👏

[@aaaaaaaaaaaaaaaaa1569]

Because electricity kills you faster than the breaker can trip. Saved you 18 minutes

[@manuelp7472]

You really think that's a smart remark, don't you?

[@Rondo2ooo]

This is the best video about the topic I ever watched.

[@Seijakukun]

so glad I spent (less than) 20 minutes watching this video. everything electricity related is not so widely know where I live, so I appreciate every piece of knowledge I can grasp!!

[@kerrywsmyth]

At work they call these “time delay” but now that you show exactly how they work with the graph, everything makes sense now.

[@Kapil__Lanjewar]

The fact that I commented on this video after 4 months it dropped and you liked it is astonishing! Thank you!

[@andreadigiacomo9102]

As electrical engineer, WOW this is a beautiful video!!!

[@tookitogo]

0:15 The other day at work, I found some extremely small-value glass fuses in a drawer, all the way down to 5mA. At first, and second, and third glance (with the naked eye) I thought they were already blown, perhaps by someone using a continuity tester on them. What’s crazy about them is that the fusible wire inside is so thin that it’s hard to see it even under a microscope with 40x magnification!

[@timothysands5537]

Phenomenal video. I thought I understood breakers, but I never once looked at the trip charts nor had I noticed the Arc chamber. Thank you for this!

[@Sornemus]

I once found an easy-to-grasp explanation of all three essential parts of home electric panels: Circuit breaker - protects wires. Residual-current device (aka ground fault interruptor) - protects people. Voltage protection relay - protects devices and appliances.

[@bkovba]

I think it'd be nice to hear a little more about why exactly the piston moves down irrespective of the direction of the magnetic field. My take is that it gets attracted by a metal part right beneath it and not 'pulled down' by a magnetic field. But please let me know if I'm wrong, greatly appreciated

[@mysterion4301]

As a young apprentice back in 1974 I was taught that the amperage you have to worry about killing you is "any amperage that is enough to stop your heart." In the US people tend to think that's either 15 amps or 20 amps because those are the most common sizes for breakers in their home's panel.

[@PlayboyHZ]

100mA is potentially enough to stop your heart. It also depends on the voltage

[@pcbona]

5:25 "This rail is not electrified" - Thank you for this information. No one ever mentions that because it is so basic knowledge to an electrician, but stepping into the shoes of a person that comes from a different area of expertise, it is not so obvious as the rail is also hidden/protected by plastic covers and cannot be "accidentially" touched.

[@TheChrush3r]

a wonderful refresher on what i learnt in trade school, just in english instead had to do some translating here and there but thanks to physics being rather... universal, its a genuinely thorough and well done video, so applause from actual electricians here

[@randomone649]

5:49 , also as an electrician, a thing I learned in school, make the connecting head like a hook shape, and try to insert the hook behind the screw, this gives it more grip and contact, making it more sturdy and harder to accidentally pool it out

[@johnchestnut5340]

Wrong connection type. That's a blade connection...not a screw connection. Forgive me if my terminology is not accurate. But they are different connection technologies.

[@gang208]

There is a type of circuit breaker that do protect people from accidental electric shock. In N. America, it is called GFCI circuit breaker. They are rated for 15, 20, or 30A as the regular breakers but they also sense the current imbalance between the hot and neutral wires. When someone touches the hot wire, it creates a current path to the ground, and this causes an imbalance which triggers the breaker. Several milliamps of current imbalance is sufficient to break the circuit.

[@michaeld9178]

As an instructor to apprentice electricians, this video is going to be on their course going forward. Brilliant job. PS video title is correct, first thing we tell apprentices is, an MCB won’t save your life.

[@mirza5373]

So much engineering compacted into this tiny device! Thanks for the explanation

[@IrisNebula7023]

Awesome video, very well explained concepts. I had to learn everything in this about a year ago, but it took a friend hinting me to the right direction and a whole afternoon of studying, this would had a been great help 😊

[@simey6327]

Around 1.30min: I believe the inner (red / blue in video) covering is the electrical insulation but the outer grey is the sheath and is there for mechanical protection. Not taking anything away from the video which was fantastic.

[@pjford1118]

In Canada the RCDs are called GFCIs ( ground fault circuit interrupter), we also have AFCI (Arc Flash Circuit Interrupters). The AFCIs are supposed to detect even the tiniest arcs, this causes more that a few issues, any brushed motor seems to trip them, and it I hit the high frequency arc stabilizer on my arc welders all my neighbors end up in the dark, The normal breakers cost ~20$CAD, the GFCIs are ~80$CAD, AFCIs are ~160$CAD.

[@EngineeringMindset]

We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: kzbin.info/www/bejne/h5qTqqGJhtxgrcU

[@mernokimuvek]

The inrush current with capacitors and inductors is not because they store energy. A dicharged capacitor appears as a short circuit when it starts charging. Iron core inductors are nonlinear and remaining magnetization can saturate the core.

[@dimitrisblane6368]

Good explanation for the caps causing inrush current. Can you explain the inductor part?

[@atquoc2721]

Sidenote for the installation of those CB (just a way to ensure safety): always connect the hot wire to the top terminal, output line always go out at the bottom terminal of the CB. If you need to go through the second CB, run the output wire back to the top terminal of the second CB. Why you need to do this? If you are not the only one who do the maintenance of equipments, there is highly chances that someone will get electric shock because they don't check the wires's condition again after switch off the CB. By doing one way terminal, the hot wire will always on top, mean if you switch off any CB, the cable go out at the bottom of that CB surely have no electricity.

[@jamesbensley7914]

Explained so well, Will save this for future teaching of remedials.

[@gedavids84]

American viewer here, I found your RCD configuration very interesting. That is not how we do things here in North America, every circuit that needs RCD and/or arc fault protection has it built into that one circuit's breaker. It's a very expensive way to do things, and has deterred me from retrofitting such devices to my older home.

[@Steinegal]

Same here in Norway, we also break both the live and Neutral in each circuit, but most households actually don’t have a neutral, but two live wires

[@ensart91]

This must be the best video that shows how MCB works. Thanks!

[@MaxPowerElectric]

So is the piston inside the solenoid just a ferromagnetic bar? If so, how does it always move in the same direction during a short circuit, if the polarity of the solenoid's electromagnetic field is constantly changing with the AC flowing through it? Is it because the time it takes for the B field to increase is so small that it's completely within the + or - half cycle (aka

[@erintyres3609]

Thank you for the video. I took apart a circuit breaker, and the mechanical parts are something like a mouse trap. A small push the bimetallic strip makes it decisively snap open. Now that I have seen your video, I also understand the solenoid and the arc chamber.

[@SpencerHHO]

Australian regulations have solved for this confusion by mandating RCDs for pretty much EVERYTHING. Even in industrial buildings and 3 phase circuits RCDs are mandatory almost across the board. We had issues at my old factory where some of the old big welders would trip the RCDs. They were changed for RCDs that would tollerate a slightly higher leakage current for slightly longer and it was fine. Not complaining though, RCDs have saved me from a darwin award atleast twice in my life.

[@RatWork866]

This is an amazing video, excellent illustrations, animations and especially: Great pace! It's exactly the right tempo to understand and stay interested!

[@jimwinchester339]

Wow - I had no idea so much engineering went into a basic circuit breaker. Thank you.

[@AlmightyPyro]

this is the best video i’ve seen about this topic.

[@PotentialGrim]

I learned this in college but seeing it illustrated instead of drawn on a blackboard really helps.

[@Amathyy]

I think their reliability is really an interesting thing. So many different stages are connected just through contact but it still works so reliable.

[@milosstojanovic4623]

Very nice to know how inside of breakers look and how they work. In our old houses we still use ceramic with copper wire breakers, they are extremely simple and they do not need replacement, just replacing copper wire inside of them :D

[@Aliefr3550]

This info is like gold for the mind, thank you for not putting it all behind a pay wall.

[@IctWilsons]

Slight quibble - the wire gauge is rated for a certain load because of its insulation, not because of anything inherent in the wire gauge (to a point, of course). For example, to save weight, aircraft wiring uses smaller gauges for given loads than building wiring, but with higher heat-resistant insulation.

[@emmaehrm7662]

I recently joined a manufacturing company and have learned a great deal about MCBs. I must say, you've done a wonderful job. Your passion and commitment to delivering high-quality content are unparalleled, especially when it's hard to find such valuable resources. You keep my burning desire to learn alive. Thank you.

[@marekgdpr680]

I recommend trying to pull wire you just connected in a circuit breaker to avoid false connections. As an electrician I already found 4 cases of false connections when I had to reconnect the wire.

[@georgemetaxas9227]

Very comprehensive video. A small remark: The arc generated at the MCB contacts is propelled into the extinction chamber by electromagnetic forces that make any arc to "tend" to move away from the direction power is coming.

[@millax-ev6yz]

If you were here, I would shake your hand, take you to your favorite pub, and buy you as many pints as you want. This video is exceptional! I've used these breakers so many times and this was an amazing demonstration and explanation. You are beyond incredible! I love your channel!

[@parthasinha7311]

Excellent video! Thanks for creating such a high quality video on circuit breakers. Learning becomes so easy with visualization of the operation.

[@aseandersen1791]

I am becoming an electrician now and you have helped me to understand electrical consepts. Thank you!

[@EngineeringMindset]

Glad to help!

[@Vea800]

Im 4th year electromechanical engineering student and this videos are a great, fast, entretainment, clever and very technical way of looking topics that are taken for granted at my university. I really appreciate it ❤

[@ojeantas5180]

im gonna call you Mr. Bugs for making this rabbit hole easy to understand. i enjoyed every minute of your video

[@lykourgakhs]

dude! awesome video! Sooo.. my breaker trips sometimes when I cook in the kitchen. Should I do lefty loosy or righty tighty on that "hidden" screw? (joking of course)

[@AJTarnas]

incredible detail. above and beyond all other explanations. fantastic work.

[@chriscockrell9495]

Now I’m curious what the difference is between a MCB, a manufacturer circuit breaker, and a plug-in circuit breaker. I enjoyed hearing the narrative that breakers do not exist to protect people, because that is something I think many people don’t often understand. I tend not to think it is simply because of the higher voltages involved, but rather the amount of energy (current) that the systems are able to source. Lower voltage systems have very different power supplies. Not just lower voltage systems but simple electronics that don’t drive major equipment (high current), but rather low current equipment. To me, because they are low current systems (micro and milli amp ranges), there is difficulty in supplying high current. The same is not true with higher voltage systems. You mentioned breakers designed to protect people which refers to, GCFI breakers, or ground current fault interrupters. Those run off a differential scheme rather than an overcurrent or a time over current scheme. Are you planning to make a video on that? All circuit breakers have similar designs, although there can be slight variations. However, all of the breakers have a fine metal connection for overload protection, a solenoid for overcurrent protection,

[@ronancollins4006]

Electricity confuses me so much and I'm trying to learn what I can from time to time and I had been wondering how circuit breakers work. This was very very informative and interesting. Thank you :)

[@antaress8128]

Very informative video. Thank you for this. I checked the breakers installed in my apartment and they are C32 for the main breaker and C25 for the rest. That's in EU with 230V plugs.

[@gamecubeplayer]

what? you have c25 breakers? shouldn't they be c16?

[@antaress8128]

@@gamecubeplayer I don't know. An electrician installed them. Not sure if he was competent or not. I'm just trying to understand that now.

[@gamecubeplayer]

​@@antaress8128i doubt c25 is the correct breaker size: 1.0mm² c6 (lights) 1.5mm² c10 (lights & sockets) 2.5mm² c16 (sockets & 3 phase ranges) 4mm² c20 (single phase ranges) 6mm² c25 (main)

[@LordRazer3]

At the last section of the video this is why some sockets will cause your vacuum to trip the breaker while other's won't. One simply has more things hooked to it. Bathrooms are normally the best place to plug in items like this for that reason since most people only have there light running from it

[@starlingmoss1812]

im an electrician, l like to say fantastic visual explanation

[@amyjojinkerson-b6o]

we in Canada use square D a lot easier

[@pahom2]

Bimetallic strip also protects from short circuit condition. US circuit breakers do not have magnetic trip mechanism for instance. Magnetic trip mechanism protects from arcing and sparking between phase and neutral wires.