This also holds true for DC Contactors (high current relays) which will have magnetic blowouts to help extinguish the arc when the contacts are opened, though the contactor will generally have a much lower max interruption current compared to a breaker it has to deal with the same concerns of arc after opening the contact and as such they will have a directionally as well. Edit: May 25th 2019 - spelling

@@cmlara5333 *contactors (The text originally said "contractors" twice. That has since been edited out, but I can't accordingly delete this comment because no one will know what the following comments are talking about. But now I have to add * directionality Aargh! No rest for the spelling-sensitive weary!)

MottyGlix Thanks for the correction! Never trust spellcheck at 2am in the morning.

I agree with you, but why are there no polarity indicators on the thing then???

@@cmlara5333 I knew what you meant anyway. Spellchecker is worse when you also have a drink in!

I was investigating DC contactors for a 240v ship-mounted crane. The ones I found were massively expensive, but one supplier rated their more common three phase units for use with DC when the load went through all three poles in series similar to your solution.

@Elektronik mal einfach True, but like he pointed out AC does crossover the 0 point at one time :) At our uni the professor demonstrated this issue with a 2kW DC loaded motor and pulled the blade switch with an arc about 15cm long - motor still running and lighting a piece of paper in it :)

Yes, when we are talking about life saving devices, it is not enough that "they should work". They have to work, every single one! I think they for some devices are talking about max 1 in a million non working units.

@@friedmule5403 Regualr circuit breakers are there to protect the cable, not your life. For life saving devices there is common sense and RCD or RCCB breakers.

@@anti4354 Okay did not know that, thought that the fast reaction time and wary low current was to save people.

@@friedmule5403 If the cable fails, it quite likely ends up in flames. Flames in your wall are far from optimal.

@@namibjDerEchte LOL central heating, is a good thing:-) No I do understand but you have to be wary unlucky to get fire inside a wall, this is almost impossible if the system is build correct.

Yeah, most have a big plus and minus marked... ABB's S800S-UC appears to be polarity insensitive, which is interesting. They claim they have two arc chutes per pole (including the AC versions), so perhaps they have a different magnetic polarity on each contact/chute? The lower voltage S200 ones do have a marked polarity.

@@someonesomewhere1240 now popular types of dc breaker are all non polarity😀we are professional manufacturer of dc breaker

thats photonicinduction's expertise

try photonicinduction or applied science

lol, for sure that would be interesting, more so if they can do it visibly :)

Look no further than the old timey Jacobs Ladder.

You can search for 'fine beam tube experiment'. It is how we did it in our physics lab.

You should make a video with the name of the brand in the title, people will buy these thinking they are improving safety, if you have real life experience of them not working, thats a huge safety issue, that people should know about.

​@@ratgreen I could. Although, I might order another one to see if the problem is persistent. I think people should understand that these items are not thoroughly tested, they barely even are, and it's like buying something on a garage sale, you can't blindly lean on it.

I highly recommend a HRC safety fuse in any case. Much more reliable and safer.

"Purple Springs" is one of my favorite bands.... So is "Powerful Springs" featuring Hidden Magnet as the lead singer. That's more appropriate for this video.

Been there, done that!! What I've found, is that a capacitor in series with a diode, then a resistor in parallel with the diode to discharge the capacitor when the contacts close will allow time for the contacts to open, before the capacitor has time to charge. That makes it so there's only .7 volts across the contacts(the forward voltage drop of the diode) the instant the contacts begin to open, which gives time for the contacts to separate, before the capacitor charges to a high enough voltage to jump the gap. When the switch is closed again, the resistor slowly discharges the capacitor, without putting extra surge current through the contacts. The capacitor needs to be big enough to provide the time constant necessary to prevent arcing. The higher the current, or the slower the mechanical speed of the contacts, the larger the capacitor needs to be. The diode needs to withstand the surge current long enough for the capacitor to charge to circuit voltage. The resistor is not critical, just so it discharges the capacitor before the next time the contacts open. I do that all the time, in circuits where relays have to switch DC into inductive loads. That works for switches, breakers, and relay contacts. In my 144 volt electric truck, the breaker was buffered by the capacitors in the motor speed controller. An AC breaker worked just fine. It was rated for 400 amps!

In pdf of AC CB is printed that it can be used for DC up to some small voltage, In some i read 48V DC, i use it up to 24V DC. That is how the relays contact work, rated on same current but lower DC voltage then AC

@@vincentrobinette1507 It will be very helpful for some of us if you could provide a simple schematic (sketch) with values of capacitance and diode rating of your solution to the arcing problem. God bless.

@@mansoorsiddique4843 I have no way to post a sketch on a reply, but, as a rule, the capacitor is sized based on the available fault current, and how fast the contacts can separate. The slower the contacts move, the larger the capacitor, The more fault current, the larger the capacitor. The resistor is based on how long it will be before the next interruption. It's only job, is to discharge the capacitor, once the contacts close. if it's a cyclic switch, like a solenoid used for a DC motor control circuit, you'll need a lower value of resistance, to make sure the capacitor is discharged quickly enough, for the next interruption. Case and point: When I worked at a convention center as a sound technician, we had a 24 volt electric cart, that was used to haul equipment from room to room. It featured a 4 stage sliding blade throttle, with three nichrome wire resistors. When ever you let off the throttle, the first blade would draw an arc, just like striking an arc welder. I fixed that, using a 2,200 uF, 35 V electrolytic capacitor, a 6 amp epitaxial "bullet" rectifier, and a 10 Ohm, 10 watt "sand box" resistor. It completely solved the problem. If the motor was stalled, or the throttle was let up before the cart moved, it would pass a maximum of ~40 amps. On a circuit breaker, you could probably get away with 10,000 ohms, because it will have plenty of time to discharge the capacitor before the next overload. Thermal stop interrupters,(push to reset button)tend to react slowly, don't have much space between the contacts, will need a larger capacitor. The peak current pulse rating of the diode is the most relevant rating, because it's only in conduction long enough to charge the capacitor up to the supply voltage. it is, however, momentarily subjected to the full available fault current. When the contacts close again, the diode is reverse biased, and the capacitor is discharged through the diode.

they have to be to work right....... unless you prefer the arc to be pushed back towards contacts ;)

How do you know which side is which?

@@mrtechie6810 there should be a diagram printed on the breaker showing the terminal with most potential. Usually marked with a +

They generally have a rating as to number of full short circuit cycles they can endure, typically for these high current units that is around 10-20 cycles of breaking before they are considered worn out. That is why they also are backed up with a DC disconnector, so that you do not use up the longer lifetime at lower current ( it is roughly in inverse proportion to current, you might be specified as 1000 cycles at half current and so on) if you are often having to disconnect the load.

Huge difference between breaking nominal current and breaking at capacity. I don't know TBH how DC MCBs are rated, but for your usual AC MCBs they are rated to 20+k cycles at nominal current (which translates to several times In for some types). However, don't expect them to break 10 Kilo-Amperes a few thousand times. That won't happen. My guess would be that it is similar for these DC breakers, except that I assume they have much lower cycle ratings for nominal current. Switching DC is *hard*.

@@dasstackenblochen9250 If you look at the specs of a breaker, you will see an AVC rating(available fault current). This is the maximum amount that the breaker will successfully interrupt, without flash over. Usually, the rating is about 10,000 amps. Any higher, and you risk physically blowing the breaker to pieces, due to the temperature rise of the arc creating a plasma.

AC has a zero crossing, which occurs 120 times per second for 60 Hz, 100 for 50 Hz. DC does not offer a zero crossing, so you don't need much voltage, or current for the arc to continue flashing over. As the current switches polarity each half cycle. If you exceed the AFC, the arc may NOT extinguish during the brief zero crossing, and will maintain an arc, just like a stick welder. you've already described what happens next!

so the magnets WOULD have more use in the DC circuit as opposed to using a magnet with the AC,,right just due to the behavior of the DC? ( like in a TV the magnets move the beam in the picture tube and its DC (highvoltage DC))???

@@sa8die Yep.

5G street light ? You mean a light pole with a 5G (mobile network) antenna mounted on it ?

I don't think they're using 5G yet. The antenna is usually just an alternative to a time switch and dusk sensor for better control. The chance of getting a faulty one is slim as they are new and expensive so they tend to get shipped back to the supplier if they're faulty.

@@bigclivedotcom Might be AT&T's Project AirGig. From what I remember of the service when I used to work for them, it was going to integrate with 5G cellular signals and basically there would be dozens of cell site towers on top of power poles and light poles to provide better coverage than the centralized towers they've been using for decades.

@@Kinkajou1015 That would make sense as the 5G frequency range has less penetrating power, so is better suited to lots of small low power beacons.

@fuckin kazars Sabotaging fossil fuel usage is likely more effective. Not that I'd encourage it. Please don't waste yourself on destroying telecommunications infrastructure. Please. Go all NIMBY on it if you _must_. But chemical pollutants are a far greater issue than whatever effects microwave radiation from cell towers has.

For dc contacts...250Vdc@125A..that tells you , at least for that much of a current flow that contact resistance must beat least (1/100to 1/500)( empirical) of (250V/125A).. i.e. {(0.01) or(0.002)×2 ohms)..

Raymond Mucklow weird mechanism! Also from flooded and tornado ridden Kansas SE Corner in my case

You guys take care, down there!!! I’m in northern Illinois. I watch the weather radar, every day, and I can’t believe what I’m seeing! We’re pretty wet up here, as well, but nothing like what you’re experiencing. (My weather station is saying that we’ve had 7 inches of rain, so far, this month.) The farmers, here, can’t get their fields planted. If they don’t get planted soon, they probably won’t plant this season. That won’t be good. Our town’s economy relies on those crops. Hopefully, this will let up soon, for all of us!!! Sending my best wishes, to both of you!!!

@@Willam_J as we speak another storm front moving in.

@@trcostan same here. SE CORNER

There are 2 magnets, in order to create sort of parallel magnetic field, so that the arc would deflect to the right or to the left.

@@nejiniisan1265, "deflect to the right or to the left"? Not at all. If that were the case, there would be no net magnetic field in the region, thus no force would be exerted on the arc at all. The second magnet is presumably there just to strengthen the field as well as cause the field lines to run parallel in the region between the two magnets. @ManWithBeard1990 is correct; if the current runs in the opposite direction, the force exerted on the electrons due to the presence of the magnetic field would be in the opposite direction, directing them into the front of the device (where the switch is), rather than the back (where the quencher is). They would still move clockwise from the perspective seen in the video.

@@JivanPal oops

@@JivanPal ABB's version (S800S-UC) is rated for use in either direction, but they claim it has two arcing chambers per pole (both AC & DC versions), so I wonder if they have a different polarity in each chamber? The lower-current version still has +/- markings.

As a Student in the mid 70's I worked a summer for Arrow Hart Switchgear. I was on the 3 ph contactor assembly line but did some overtime on their DC breaker line. I always remember the really big (as in half-inch diameter) cadmium plated contact pads I was resistance-welding onto the conductors going into the DC breakers.. These pads were rated for 200A max, so I'd be surprised if the contacts on BC's breaker were good for not much over 50A.

Very good point nut I doubt they would interact. They aren't powerful enough.

@@leonardjwright They seem to be neodymium, and they are on both sides, so only 4-5mm apart if two or more of these breakers installed on the same DIN rail next to each other..

Erm, that's not my experience. At least with relays and contactors used in avionics. They are usually rated at the same current for both 28 VDC and 200 VAC (400 Hz). The voltage matters, but also whether it's DC or AC.

Worse still that many solar systems are basically being installed by crash certified labourers.

How is the polarity marked?

@@mrtechie6810For single pole breakers there's is a diagram on the front but also they will usually have a + at one end and a - at the other end ,this is for single pole breakers ,for double pole breakers its slightly different .

As I understand it, the arc induces a magnetic field which is then pushed into the quencher by the stationary magnetic field of the magnets, and the movement of the induced field drags the spark into the quencher as the spark follows the induced magnetic field.

Usually only to 48 or 72V - I think Schneider is 48V only.

@@someonesomewhere1240 No, considering we were using 400v DC in some instances, I had to check with Schneider, they certified the breakers as being capable to take the rated current regardless of whether the load was AC or DC and the voltage rating was the same for both. If you brought an MCB or MCCB there was no down rating just because its DC. Consider that this was for large scale commercial Datacentres I was most insistant in getting that in writing as any downtime was measured in the millions of pounds per second. I had to be sure.

@@jeremytoms5163 That's interesting as that's contrary to their datasheets: download.schneider-electric.com/files?p_enDocType=Catalog&p_File_Name=CA908061E+(web).pdf&p_Doc_Ref=CA908061E Perhaps you were using them for off-load switching (DC-20) only? There's generally noissue with carrying the load, only breaking it or interrupting a fault.

Someone Somewhere This is where it gets interesting, page 34 of the activ-9 catalogue. DC rating is 133vdc for 2&3 pole and 250vdc for 4 pole at 10kv , breaking capacity. As I said, I had to check as I'd read the same spec you had when I took over the DataCentres . I wondered how the install teams had got away with installing these breakers on Low voltage DC and so went to the technical team of Schneider for answers. I was lucky in that I'd dealt with them before on a few 11kv substation builds so already had contacts. The letter I had came from Schneider Technical in France. I emphasised that we were talking about DC not AC and they were quite unequivocal that their breakers would be rated the same both Volts and amps on DC and AC. Must admit that I was glad about that. Do you have any idea the hundreds of circuits we would have had to re-engineer across 7 DataCentres and 15 Nodes ? Can you imagine explaining to your customers that the previous installs were buggered and needed to be ripped out and by the way we're not sure if we can safely carry the load whilst we start rebuilding? That was a very anxious couple of weeks. One of the reasons that I hate DC in DataCentres, such a pain in the arse all round.

@@jeremytoms5163 I'd be most interested to read that email, given even load-break switches need to be massively over-rated for low-voltage DC.

Surely, you will eventually have to replace a defective one. If it isn't too badly damaged, that might be a candidate for a deconstruction and inspection.

It's impossible not to have a good day while taking apart something and discovering how it works.

Can you cook hot dogs on it?

@@dsloop3907 Pretty much. My fingers certainly feel cooked after touching it.

I'd be cautious about using this in a real scenario in critical applications. It might be fine for a low power remote application that didn't pose risk, but I regard stuff like this with no real local certification and testing as prototyping materials. It's better to use a properly certified unit in a real application to avoid liability.

Thanks for your answer! I agree. But if or if not it will be ok to use is still rather speculative without testing, which i know is outside the scope of this video. But maybe for a next video i would be very interested to see what’s the difference is between a din rail model from this video and a waterproof automatic resettable DC fuse/breakers for cars, audio systems, boats etc and are in the range of 30 to 300A also china made and from Ebay, Ali etc. Gr Luc

@@LucScheffers Cars are much lower voltage. Most reputable manufacturers' mains-voltage breakers are also rated for DC at up to 48, 72, or even 125V. Some have a *minimum* of 12VDC.

@@someonesomewhere1240 thanks for your input!

Looking at the video the sticker seems to read 250V DC.

@@blahorgaslisk7763 Those magnets are a lot more effective than I thought.

The Nader NDB1-125 looks identical to this one. Label on breaker shows AC230/240. Spec sheet shows 60vdc.

But at some point the current waveform will be zero regardless of power factor.

They do the AC breakers in clear plastic, but I'm not sure about the DC ones. You can't see the contacts in the clear breaker because they are in the arc containment area.

@@bigclivedotcom Ah yes that would be pointless then , shame you cant get them apart without parts pinging off the ceiling but they all seem to do that . Thanks for the reply.

Tony Papantoniou Amps don’t matter in arcing, voltage does. So a 10 million amp source at .000001 volt won’t arc under standard temperatures and pressures but a 10 million volt source at .000001 A could arc several feet. Which is exactly why high voltage distribution towers look like they do to keep the transmission voltages as far away from ground and each other as necessary. FYI minimum arc is 10kV in dry air, the reason you see household stuff arc in the sockets has to do with inductance and collapsing magnetic fields creating high voltage.

@@peterg.8245 DC needs bigger gaps on switches as it jumps further and quicker breaking

With DC we'd have been stuck with brush motors for a long time. Personally I'm not a fan of brush motors.

Brushless motors are ac motors with built-in dc to ac inverters. So without the idea of the ac motor, no brushless dc possible,,,

If it's not, it should be.

You'll have to follow the specific DC MCB's data.

All breakers have a trip curve based on a thermal response to a low overload and a magnetic response to a fast overload. A 120A breaker will trip with varying time above 120A but have a margin above that value where it will not trip. Buying a prominent brand breaker in your country and observing the correct installation procedure is the best option.

@@bigclivedotcom Thank You so much for the @ sound of speed reply!! now my next thought is what if i get a 80A's dc breaker ? also i will set up on the + wire a anl fuse , the breaker used mainly as a switch ( wen i need to disconnect the "Y" paralell union) and a fuse as a over current cut off . Have you tested ANL ( or that kind of fuse ) if not i will gladly ship you some for you tp play with , i dont have gear to do test's of that type ,Cheers & Best Regards

The labeling claims 10 kA(!!!) breaking capacity at 250 Volts DC(!!!!). Even with that 2x2x2 cm arc extinction box, that seems like a very bold claim to me.

10 kA is quiet on the low side of breaking capacity for these breakers. The AC breakers here in Germany have a minimum rating of 10 kA for household installations. On industrial installations they require a braking capacity of 20 kA. Edit: Had it wrong. See Gaunerchens comment below.

@@sebi7794 Yeah but that's for AC. Not DC. Totally different beast.

I'm with you, arjovenzia. That contact area is questionable, even for a 'one-use' purpose, and the separation when the contacts are open seems woefully inadequate. 125 A DC is into arc welding territory, and they're relying on a 'standard' sized contact, maybe 3-4 mm diameter, separated by about the same distance, to break that much current? At 250 V?!

It's that TOMZN chinese crap.. so probably lucky if it's actually break 24V never mind 240V DC

@0.15 you can see it's rated for 250 v

@@ginvr Doh! ...... You must have better eyes than me! I turned it on to full screen and then only just made it out (well that is my excuse and I am sticking to it)

The blowout coil solution does seem more elegant than the permanent magnets, at least when you go up higher in current and voltage.

SigEpBlue actually you may be right ,you know..passing that much current through that thing,doesn't end well.

At 125A the contacts weld together in a big blob of molten metal. They have no problem carrying 125A from then on :)

Somebody (can't remember who) did a video about an ancient submarine breaker. It had something like a sacrificial contact.

@@bdf2718 Photonicinduction did.

@@atonduke7612 I had a feeling it was him. And then I remembered the video was rather calm and controlled without flames and bangs, so decided it couldn't have been him.

No. It's not a recognised brand here.

Yes. Fuel consumption of cars. Even if charlatans claim otherwise. And let's not even begin on "health" magnets...

Most small breakers rely on an arc characteristic that causes it to follow shaped rails that carry it into a stack of isolated metal plates that break the arc.

@@bigclivedotcom thanks Clive. For the arc to travel through the plates, is it still connected to the powered side, on one side of the plates (to direct the flow of electrons through the plates)?

it had 250V on the label....

Not that type. Do you mean the small aerial that allows central control of all the lights?

@@bigclivedotcom the ones with the 5 G ready knob on the top

The block for quenching the arc on some breakers is called an arc chute. This is a trade name such as in your web browser, is it bookmarks, favorites, or something else?

So many that even Griswold will go "maybe that's enough".

Depends. Do you want to light up the leds or also the cables? ;)

@@adlerweb should i use 370vdc or 850vdc ???

Do you know PhotonicInduction?

It literally has "DC 250V" written on it lol

Should be safe, as long as you get one designed specifically for DC at the current levels you're expecting. Using it at lower voltages just results in a lower energy arc when they trip.

@@MegaFPVFlyer nice to have that confirmation. was thinking it may be an energy trip not a current trip.

AC current and voltage go through 0v/0a 100times a second, this breaks the arc much easier and usually limits how long the arc will last for. DC however doesn't do this, once the arc is started the superheated plasma conducts the electricity and reduces resistance and unlike AC it is always at full current and voltage.