If you have 250 volts through a low voltage breaker, it doesn’t matter what the amp rating is. It can burn up AFTER you turn off the breaker. DC arcs are crazy powerful. I use 1000 volts breakers on a 250 volt array and pay attention to the polarity marked breaker.
A very clear and great example of DC arcing. Low voltage DC switches around 12 - 24 volts do not arc very much but solar systems can have voltages up to 400VDC. Breaking the circuit under load causes a long arc which is longer than the open (off) gap in small household breakers. As an apprentice (many years ago) I remember building DC contactors for 415VDC. These were very large mechanisms with special rolling and pointed contacts with make and break under a large fireproof hood! Great video, really demonstrates well the problem!
There is the rated operating voltage too that is very important. As an example, operating a 150v disconnect switch on a 350v array would give the same result.
@@rm6857 i was about to abandon my project just because i watched this video... but then i wonder if the same would have occured if he used a 1000v 16a double dc bracker on a string that produces 14 amp in short circuit mode like i'm going to do... any opinion about it is very welcome
Thank you. I worked on a lot of laboratory equipment. I learned to read and reread the manuals, then ask the company engineers and technicians questions. It eliminated problems and downtime. And I am still alive and have all my fingers, etc.
I think its the chinese one cuz there diagram on the right and blank on the left. Probably 240VAc/125Vdc or something. That was why he hid the right side of the the breaker.
Wow ! Excellent demonstration. Use of a much higher DC rated breaker, voltage and current, is clearly needed than the installation normally provides. Trouble is in an emergency the isolation switches would always be used so they must be rated for Live switching as well as Isolation. Adds to costs but so would a fire.
For those not in Australia, or even those in Australia, there are manufactures of breakers with magnets and arc chutes to quench an arc for high DC interruption. They are designed to open under load and quench the arc. Please note they are polarity sensitive as the polarity determines the direction of the arc blow in the magnetic field. Polarity must be observed to blow the arc into the arc chute instead of away from it. Many breakers for DC have low voltage ratings due to the difficulty in quenching an arc. For panel arrays, ensure the breaker is able to quench the open circuit voltage under load. Other DC disconnect devices have multiple series contacts to break the arc. Large gap knife switches work well as the gap when open is more distance than the current can mantain an arc. Use the type often used for inductive loads such as for a heat pump disconnect switch. Double break and an open distance greater than 1 inch is good to stop the arc. The distance is important the same way cutting the cable broke the arc. You need a large device with the ability to make a large gap when open. For over current protection, use the sand filled multi-element fuse for at least the rated voltage. The sand falls into the arc to quench it.
as an apprentice with 2 years of solar installing experience, ive seen the crusty smelly shells of the Zbenny isolators. But to see how quick the switch goes on fire was eye opening ty
For any DC interrupter device, voltage rating is absolutely critical. Larger voltages require an exponentially more robust arc chute control. A 100V disconnect on a 500V circuit at any current is going to be a blast, even at 1A. DC is a completely different animal than AC.
That is why DC disconnects have large gaps. If you have to turnoff under load no fire will happen. Also not having a large enough disconnect (using a 12 volt disconnect on 310V. All solar disconnects should be rated to 600V minimum. Mine are 1000V 64 amp. Mine shutoff 330V 15 amps . This was a great video thank you. Also I would not use the inverter disconnect first. I would use a wall mounted with fireboard disconnect like you have then turn of disconnect on inverter 2nd. then reverse for on.
Excellent demonstration reinforcing the need to implement the correct type of switching device. Until you see how it instantly ignites it’s hard to have an appreciation for the risk.
Awesome breaker fire. Just love how quickly it lights up and burns. Some breakers due to age will prematurely trip causing the same break under load condition. Was a stupid idea to have them in the first place, hence why it's now obsolete.
Thanks Brian, yes it surprised me just how quick it went up. And yes your spot on about the breakers simply tripping through age, fatigue, external thermal influences etc. This one was in spec for the application also.
My 150vdc midnite solar breakers have worked flawlessly on my 80vdc system. Put too much charge controller on an array and it popped 80 amps repeatedly
Wow, read the title, came into this video expecting you to be critical, but wow.... Great demonstration. Really making me take a second look at my disconnects.
This video assumes people can't learn. I understand the concern, but that is a ver elitist view of the world. I built my first system last year after I did about 100 hours of research. I already replaced components that had been recommended, but turned out to be faulty.
Hello! Really good and informative video but one question: what was the voltage in the system? I am looking the datasheet of Eaton/Moeller PLS6-C16/2DC breaker and there it says it's a proper DC breaker rated to 220V DC. It doesn't say anything about the arc extinction/reduction in the datasheet but I would assume that when used in accordance to the spec it shouldn't just ignite like it was seen in the video. So I am wondering what actually caused it to fail... Was it already broken? Was it some cheap fake? Was it used in the system with much higher voltage than rated for? Something else?
Do you check the current direction? Moeller change to Eaton 264902 PL7-C16/2-DC and on it you can see a plus and a minus for the direction of the current. That will be interest for me.
I’m sure you meant well with this video but you need to either redo it with the needed information or add the info to this vid. What you are saying is the correctly rated breakers they used to use in PV systems will catch fire if you turn them off under load? Because that is what I got from the video. So the DIY 200 watt 12 volt panel and inverter I have on my shed that uses a similar breaker will burst into flames the moment I switch it off?
I only use midnight breakers. MNDC breakers marked with polarity in mind because you want the arc to extinguish in the same direction of the yolk. If you wire DC breakers backwards it will actually hold the yolk in the closed condition in some scenarios. That would be bad. The 600 V breaker that midnight solar makes actually has four yolks. thanks for making the video. It’s very important to understand how DC arcs pertaining to these breakers work.
Very good demo Joon Ive been banging on about how DIY (amateurs) are so casual about dc distribution - but I just a a big yawn from forum members (like Im a party pooper). One thing to note is that an arc can be killed by distance (for a given voltage). Its not possible to sustain an arc at 12vdc from a car battery. Use a 24 v pair and you can do dc welding. But pull the rod away from the work by more than ca 1/2" and the arc goes out. My take is to stay at 24v its much safer. 48v might need a 2" separation (tbc). I believe the very common domestic 63A knife switch (ca $10 us) would do the breaker job very neatly at 24v (48v tbc?). These are all over the far east and solid reliable, as are the Siemens NH style knife fuses ($5us). IMHO there's a massive cartel trying to monopolise the Solar DIY market and its rife with fraudulent parts - fake cable (4mm2 labelled as 6mm2 etc)
Thanks for this Joondalup, but I am confused. At around 4:40 you say the inbuilt breakers are approved to operate under operating current, and then you say that they should not actually be switched off under load because of the strength of the DC current arc. Where then am I supposed to break the current under load, or should I just never turn them off under load? Anyone?
Yes good point and sorry for the confusion. I explain better in the next video I am currently doing. If you turn the solar controller or string inverter if ac coupled off first then the current flow will stop. Then it is safe to switch off the dc breaker.
I have used a DC breaker in that style. 1000v 16amps. No issues switching. Obviously that brand you used has simply not be designed to operate at the voltage and current used or it's a faulty design. A DC breaker of that style should follow it's ratings. What brand breaker was that? was it an AC breaker?
In my inverter manual it states, never disconnect under load. I guess the same applies to battery disconnect. Would a disconnect fuse be safer as it is manually disconnected ?
What is the voltage going into the breakers? If one is doing a 24V or 48V system, it should not be so easy for arcing to occur when breaking the circuit, right?
EE here. I laughed and laughed at the video and the title. Watch me light this pile of hay on fire to prove that hay is a bad idea. So much wrong here, I wouldn't even care to start.
To be fair, it's a sobering look at what happens if you don't understand what you are doing. It's not like this stuff isn't fully available DIY. I am not really sure how having the isolator IN the inverter solves the issue of wanting to isolate something, but what do I know. The UK have "banned" DC switch isolators on Solar panels in their new wiring guide. I'm going to keep mine. I may be stupid, but I don't see how the individually fused lines won't work. And my ratings aren't for toy voltages and currents either. I'd be nervous if they were on my house roof at this point, not gonna lie.
@@joondalupelectricalservice3201 if we need under some situation like short circuit on Ac side so that y i ask i have inverex 12kw inverter which have built in disconect switch on side of inverter
to protect dc load you must use breaker with proper interrupting capacity at that dc voltage and having number required of poles in series as a representative for the correct number
so i have a DC isolater rated for 1000v 63A but i am only running 250v 20A ,,would that one also go to smoke , if i break the circut in high sunlight? i have only turned it off early morning or late night...
Hi. I am now planning to arrange a solar system, and looking into various issues I might run into. :) Yours is a great input, one thing that concerned me, when you were explaining at ~5:30 you take the wire connected to breaker '-' contact and say it is '+'. Is it possible that you changed the polarity, and that is why the arc went not in the extinguishing chamber, but went the opposite way into breaker 'insides'? Thank you
Hi With these ones no matter if they were wired correctly (positive to negative flow of current) they would still do this. I will do another video soon to better explain.
That jumper doesn't seem right? All the schematics I have looked at show 2 methods on battery side going in. 1324 and or 1234? I am glad I haven't screwed anything up yet. I am waiting on some 4/0 cable and some DC cutoffs. Resetable 300 amp breaker. Lug crimp. Stuff. Everything is so expensive.
Your breaker needs to meet not only current loads as well as break voltages. If your sized correctly, then your over current protection device isn't an over current protection device.
What if there is no load, but only batteries that are being charged. Can you still turn off the isolator while the batteries are being charged? Since the battery is like a load. Or do we need to turn off the breaker for the battery before turning off the isolator for the pv array.
Go with 1000 Volt inline fuses. When they open a temporary inert gas is given off inside to assure a voltage breakdown will not occur. Way safer than air breakers. DC has no zero crossing so it is harder to remove a breakdown ark.
it's good to be aware of the risks but this video is incomplete and misleading. no info about the breaker ratings, solar open circuit voltage, if the breaker is wired correct polarity, etc. moreover, those extension solar conductors increase the total inductance and therefore the arc energy which may be beyond the breaker can handle.
I don't know if you plan on doing a followup on this one since it's now a year old but if you do, do the short circuit test as in this clip, but also show the same model of device interrupting the PV on inverter drawing Imp off the array. It might be eye opening to some of the other people that have posted on this video about their MCBs and how they haven't caught fire ... yet.
I've tested quite a few breakers here in the US under a DC load. 92 volts DC. Its interesting, because our standard AC breakers like Square D homeline breakers stood up better than the actual DC rated breakers I had. None pf them failed to extinguish the arc. Although the breakers I was using where rated for 5ka but the homelines where rated for 10ka which probably had a loot to do with it. Would be very interesting to see more breakers tested under DC load, even ones that aren't DC rated since that seems to be a thing that is done a lot too.
Remember the types of breakers out there .The best breakers are thermal sensing ,current sensing and magnetic tripping .Also operating voltage gives it the ability to extinguish and ARC ,Always she's the load in the panel before you open the main breaker .Same thing with fused disconnects protecting panels .Also there are HP ratings to contend with ,not just current and voltage and ratings AIR and most important .NEMA vs IEC .I'll take NEMA every day over any IEC .Just remember if your short circuit current is 10 amps don't put in a 15 amp breaker or fuse for that matter even if the wire is rated for 30 amps ...As the voltage goes up you will need devices with arc chutes for quenching the arc .Some uses several contacts in series for arc quenching
"dont fuck with these" !!!......as a sparky in the states, i can attest, to the lack of knowledge most of them have. especially with DC voltage/currents. thank you for the show !!
Thank you for making this video, this is very very helpful, might even save some lives! Just curious, do you think it's safe to say that all Cbreakers with that similar design (possibly rebranded) are equally as bad as this one in the video?
Noark breakers come in 1000v and 450v. Most inverters are 500v now. So if you mess up and put the small breaker in, which is easily done if you have loads laying around. Magic white smoke.
Actually these so-called dc circuit breakers are not designed for dc at all. A proper dc switch or breaker will be physically a lot larger, have proper arc shields and arcing horns all built in. What is currently used is a re-branded ac breaker. It can still be used with dc, provided you wire up a "snubber" circuit in parallel with the circuit breaker. This should consist of a resistance in series with a decent size capacitor and the arcing problem is solved.
I'm not a PV installer or even a "spark" but my understanding was that in PV panels the Voltage remains constant and the Current changes due to light conditions. Please be mindful if you reply, I'm a mechanical engineer not electrical!
Mostly. Only complication is that the open-circuit voltage is a fair bit higher than the optimal operating voltage, so you need to rate your components accordingly. A panel sold as '12V' will usually be able to output 20V under no-load conditions.
@@vylbird8014 22 or more.. 18v at maximum power point. They sold as "12v" panels, because that's the target nominal battery voltage. You need somewhat higher voltage than the battery charge voltage (~14.4v on a nominal 12v battery). Just adding info to your already informative comment, for others.
the dry air has a breakdown voltage of 3kV/milimeter, if the air is wet, this value is lower. if the distance between the contacts is 1 milimeter and there is an arc between them, it means the voltage is already kV. due to the parasitic inductance of all the wires where the current flows in a closed loop system, if you open the loop, the parasitic inductor tries to resist current change and it will increase the voltage creating an arc until all energy of the inductor is dissipated and the voltage returns to that of the PV panel/string. if you want to minimise the arc, keep the wires as short and thicker as possible.
@@joondalupelectricalservice3201 Why experiment, this is trustable brand dc breaker, its rated for 220V DC so you are more than 150% of its rated voltage. Do you have any education in electrics? or you just try experiments if breakers burn or not?
A capacitor in parallel with the panels, and a capacitor in parallel with the load would prevent that. The capacitor voltages would be equalized when the cutout is closed, and would maintain that 0 voltage potential long enough for the contacts to separate enough, that the peak voltage difference cannot cause an arc. The capacitors have to be sized for the current of the panels, and, the separation speed of the contacts in the switch. A knife switch needs large capacitors, a spring loaded breaker can use smaller caps. The scariest thing about photovoltaic panels is, that if loaded down to ~80% of open circuit voltage, they become a constant current source. Once an arc is established, that arc can be drawn out to several centimeters, depending on the voltage of the string! The breaker shown in this video only has about 5 millimeters of contact separation when open. It will barely even reduce the current transferred to the load.
it is a great heads up but the title is a totally stupid approach. You could help a lot of people to address the critical points and demonstrate how to avoid the pitfalls. If you make a series doing just that I would even subscribe. Saying "DYI and Off-grid is a bad idea" will just alienate viewers and for sure nobody who would otherwise be willing to build a solar system by themselves will say "oh this video said it was a bad idea so I will call an installer to charge me an arm and a leg for pointing at a decent isolator". Whoever is up to the challenge (like myself) is totally interested in the possible issues and the right approaches to avoid them but will definitely not be scared by the fact that wrong connections can cause fire - no sane person in the world will assume it is safe to connect electricity the wrong way. You could and should say everyone should do their homework, research the subject and may guide them to some reliable sources of knowledge. You can absolutely warn viewers that if they screw it up it will burn like this and even worse (you did not even talk about lithium battery fires). "why DIY solar and Off Grid is a bad idea" - it just looks like a contractor trying to secure more job. Which btw I don't really think you want but it looks very close.
That‘s why i dont use breakers at all. Although i only have 200 watts of solar. I dont know why i would want to disconnect my solar panels? I just remove the cable from the charge controller. Also the voltage isn‘t dangerous in my case
@@richardjones3112 As long as you are using a DC breaker that is rated for the load then it is safe to disconnect. But you should never disconnect MC4 connectors when they are under load.
@@BlueSky-cy5nw I agree with you 100% but why would you have an installation that didn’t have the correct isolators fitted in the first place?I can’t get my head around how that could be possible.
@@richardjones3112 It's not intentional. It's just that there are a lot of cheap DC isolators out there that don't meet specifications, or have the proper certifications.
You missed the point (it happens ;-) ), no fire happened during the short circuit. The fire happened when the short was *disconnected*/opened and the resultant arc was not interrupted . Solar panels can be shorted indefinitely as the cabling is rated for that , and panels can't supply more than that (unlike most batteries). Solar panels can't only supply a limited current to their loads , a short is no different than a heavy load, they will just max out to their Isc amp rating and that's it (voltage will drop). However when you interrupt it under max load.....that what we see in this video.
@Bushcraft1974 You can fit an external DC switch to your DC in cable. You can also put an arc fault detector in your fuse box. In the UK we also only use serial string inverters with lower Amps higher Volts which also helps eliminate arcing.
The panels don't run at their maximum current, thats directly proportional to the irradiance. They tend to run at maximum voltage. If you add optimisers or micro inverters then the opposite becomes true.
I have done my own offgrid, I used DC rated isolation switches and everything is in a durable metal enclosure, to be fair I have heard of plenty of professionally installed installations catching fire, and the classic stupid mistake is installing inverters in lofts. This stresses the electronics in hot weather, also people have been known to pile old bed linen and Christmas decorations around these inverters, leading to even greater thermal stress and fires.
Rule of thumb 10kw inverter for every 7kw of demand ..Leaving 3 meters of space around your inverter is essential .Also the same rules apply for the derating of conductors based On ambient temperatures .You drop your ratings if your inverters ambient temperature is at 50°C like in attics and lofts in summer .Derate again for that and you may be only able to run 5 kw on a 10 kw inverter .Adding fans for cooling is essential and fresh air. in many cases the attic temps are much higher than outside .More fans !Or water cooled heat exchangers
@@scottwilliams5196 there is no such thing as free energy or green energy .This is the problem going from a reliable power source to one that is not .Solar has its uses so long as you have the ability and space to provide more power than what you need and the ability to store enough surplus to operate for 1 to 2 weeks .Let's face it we have many cloudy and overcast days and at times for weeks in a row .It's not a reliable power source but a means of augmenting a power system .All you are doing is off setting the carbon foot print to a later date .They are highly toxic ,have a relatively short life span in some locations and have issues with maintenance and need to be cleaned to keep efficiency up .I like solar,don't get me wrong but it has its issues and has limitations and they do harm the environment from manufacturing ,disposal and the change in temperature in the area they operate .So do wind mills ,they kill wild life and redirect air flow and introduce noise that can be harmful to animals and humans .Basic laws of physics .(Energy Can't be Created, Only Transformed From One Form To Another )And that's that !You can't get something for nothing .Everything has a cost
@@carlubambi5541 my tool box has many tools. I don't reject a tool because it can't do everything. Solar has been a great tool for me. Wind would be a good tool as well. Grid is a good tool. My panels will long outlast me and probably the next person that comes along. I replace batteries in my solar like I do in my cars, truck, mower, generator and power tools. We all do that. Not complicated. If you don't want alternative power, cool for you. Enjoy that choice, but don't dump on others who try to think outside the box.
@@scottwilliams5196 yes I agree it has many uses ,it's a tool like anything else .It's has its uses and limitations,and should not be promoted as a be all and end all and cure for an imaginary enemy nor as a cure to solve an energy problem that does not exists .You see the more energy is produced the cheaper the price ,the problem becomes at what point will it be profitable for the produces .Eh Pickering nuclear plant produced electricity at a cost of 4 cents per Kwhr over its life span .This cost includes the building and maintenance .Distribution is another head ache and cost .The end user was paying about 6 to 8 cents per kWhr .they now privatized electricity and now we are paying as much as 10 times .for the same electricity .We are paying between 50 to 80 cents per KWHr for solar and Wind .!Something is seriously wrong . If I had the space I could put in about 4 kw of solar .The cost would be too high and the recovery too long 20 to 30 years before you break even .I have 400 watts on my shed to charge my tools and lawn mower and supply security lighting .It would cost me $3k + to run a wire from my house to the shed .So I spent$1500 for a stand alone solar system .The batteries are the biggest cost at almost $400 each .I use 2 RV marine lead acid batteries and a 1500w inverter .That's more than enough for a stand alone power system .When the power does go out I use a back up generator .
You know it’s wired not correctly - it clearly failed on right one that was done in reverse and of course overcurrent device should break under load… so that statement is absurd - not sure what is Your intent since You know that because You mentioned there are non polarised one that I use. So case is there is no lack of knowledge on your end - there is another motive - wondering what?! Can you explain motive?
If you have 250 volts through a low voltage breaker, it doesn’t matter what the amp rating is. It can burn up AFTER you turn off the breaker. DC arcs are crazy powerful. I use 1000 volts breakers on a 250 volt array and pay attention to the polarity marked breaker.
A very clear and great example of DC arcing. Low voltage DC switches around 12 - 24 volts do not arc very much but solar systems can have voltages up to 400VDC. Breaking the circuit under load causes a long arc which is longer than the open (off) gap in small household breakers. As an apprentice (many years ago) I remember building DC contactors for 415VDC. These were very large mechanisms with special rolling and pointed contacts with make and break under a large fireproof hood!
Great video, really demonstrates well the problem!
Thank you sir 👍🏻
There is the rated operating voltage too that is very important. As an example, operating a 150v disconnect switch on a 350v array would give the same result.
That breaker is rated for 220V DC
@@rm6857 i was about to abandon my project just because i watched this video... but then i wonder if the same would have occured if he used a 1000v 16a double dc bracker on a string that produces 14 amp in short circuit mode like i'm going to do... any opinion about it is very welcome
@@michenji It burnt because he used 220V breaker for 350V system. If you use 1000V for 350V, you are fine.
Thank you.
I worked on a lot of laboratory equipment. I learned to read and reread the manuals, then ask the company engineers and technicians questions.
It eliminated problems and downtime.
And I am still alive and have all my fingers, etc.
Just curious, what was the line voltage for this demo?
Can you provide the full spec of that burnt circuit breaker? What is the Voltage feeding that circuit breaker?
I think its the chinese one cuz there diagram on the right and blank on the left. Probably 240VAc/125Vdc or something. That was why he hid the right side of the the breaker.
@@mythuan2000 even if not Chinese, rating is only 220vdc and it’s not an isolator. It’s a breaker.
Thanks. Keep schooling us, keep saving lives. You may have saved my life as I’m researching solar install
Thanks legend
Wow ! Excellent demonstration. Use of a much higher DC rated breaker, voltage and current, is clearly needed than the installation normally provides. Trouble is in an emergency the isolation switches would always be used so they must be rated for Live switching as well as Isolation. Adds to costs but so would a fire.
For those not in Australia, or even those in Australia, there are manufactures of breakers with magnets and arc chutes to quench an arc for high DC interruption. They are designed to open under load and quench the arc. Please note they are polarity sensitive as the polarity determines the direction of the arc blow in the magnetic field. Polarity must be observed to blow the arc into the arc chute instead of away from it. Many breakers for DC have low voltage ratings due to the difficulty in quenching an arc. For panel arrays, ensure the breaker is able to quench the open circuit voltage under load. Other DC disconnect devices have multiple series contacts to break the arc.
Large gap knife switches work well as the gap when open is more distance than the current can mantain an arc. Use the type often used for inductive loads such as for a heat pump disconnect switch. Double break and an open distance greater than 1 inch is good to stop the arc. The distance is important the same way cutting the cable broke the arc. You need a large device with the ability to make a large gap when open. For over current protection, use the sand filled multi-element fuse for at least the rated voltage. The sand falls into the arc to quench it.
as an apprentice with 2 years of solar installing experience, ive seen the crusty smelly shells of the Zbenny isolators. But to see how quick the switch goes on fire was eye opening ty
For any DC interrupter device, voltage rating is absolutely critical. Larger voltages require an exponentially more robust arc chute control. A 100V disconnect on a 500V circuit at any current is going to be a blast, even at 1A. DC is a completely different animal than AC.
Amazing, thanks this helps me understand the power of DC loads
I am always looking for good videos on breakers and solar stuff. This was a great video. thanks! earned a new sub
Can we please get more details about that breaker?
That is why DC disconnects have large gaps. If you have to turnoff under load no fire will happen. Also not having a large enough disconnect (using a 12 volt disconnect on 310V. All solar disconnects should be rated to 600V minimum. Mine are 1000V 64 amp. Mine shutoff 330V 15 amps . This was a great video thank you. Also I would not use the inverter disconnect first. I would use a wall mounted with fireboard disconnect like you have then turn of disconnect on inverter 2nd. then reverse for on.
What voltage is that breaker rated at?
What voltage are you using for the test?
How many ka is the breaker rated for?
its rated 220V, and he uses 350V
@@rm6857 obviously he's using more than it's rated.
@@electromechanicalstuff2602 Yes, that breaker is good brand with CE rating.
Excellent demonstration reinforcing the need to implement the correct type of switching device.
Until you see how it instantly ignites it’s hard to have an appreciation for the risk.
Incorrectly wired DC breaker is a fire hazard. Wire it correctly and try again.
Awesome breaker fire. Just love how quickly it lights up and burns. Some breakers due to age will prematurely trip causing the same break under load condition. Was a stupid idea to have them in the first place, hence why it's now obsolete.
Thanks Brian, yes it surprised me just how quick it went up. And yes your spot on about the breakers simply tripping through age, fatigue, external thermal influences etc. This one was in spec for the application also.
Year 4 of running my DIY 10kw solar system. No issues at all so far. 🤷🏻♂️🙄
My 150vdc midnite solar breakers have worked flawlessly on my 80vdc system. Put too much charge controller on an array and it popped 80 amps repeatedly
Wow, read the title, came into this video expecting you to be critical, but wow.... Great demonstration. Really making me take a second look at my disconnects.
Thank you
The whole thing is if you don’t know what you’re doing don’t do it
Yeah, it's pretty much common sense. If you can read and understand what you're reading, you can do it the right way. 😏
Or do it anyway and learn the hard lesson. Then next time, you might stop to research what you're doing. Eventually you'll learn or run out of money.
This video assumes people can't learn. I understand the concern, but that is a ver elitist view of the world. I built my first system last year after I did about 100 hours of research. I already replaced components that had been recommended, but turned out to be faulty.
Hello!
Really good and informative video but one question: what was the voltage in the system?
I am looking the datasheet of Eaton/Moeller PLS6-C16/2DC breaker and there it says it's a proper DC breaker rated to 220V DC. It doesn't say anything about the arc extinction/reduction in the datasheet but I would assume that when used in accordance to the spec it shouldn't just ignite like it was seen in the video.
So I am wondering what actually caused it to fail... Was it already broken? Was it some cheap fake? Was it used in the system with much higher voltage than rated for? Something else?
No, he used 350V solar array. That DC breaker is good brand with CE
it seems that the dc breaker wasn't good enough or the voltage used was higher than its specs. @@rm6857
Do you check the current direction? Moeller change to Eaton 264902 PL7-C16/2-DC and on it you can see a plus and a minus for the direction of the current. That will be interest for me.
I’m sure you meant well with this video but you need to either redo it with the needed information or add the info to this vid.
What you are saying is the correctly rated breakers they used to use in PV systems will catch fire if you turn them off under load? Because that is what I got from the video. So the DIY 200 watt 12 volt panel and inverter I have on my shed that uses a similar breaker will burst into flames the moment I switch it off?
Very good comment/ question!!!
No, the breaker in the vid looks like its Moeller PLS6-C16/2DC and its rated to 220V DC. Modern systems operate at a few hundred volts DC.
So what happens when the customer forgets to turn off the AC load before the DC ? Would have thought this would need to be fool proof..
@@hasger1941 Exactly-it should be fool proof.
I only use midnight breakers. MNDC breakers marked with polarity in mind because you want the arc to extinguish in the same direction of the yolk. If you wire DC breakers backwards it will actually hold the yolk in the closed condition in some scenarios. That would be bad.
The 600 V breaker that midnight solar makes actually has four yolks.
thanks for making the video. It’s very important to understand how DC arcs pertaining to these breakers work.
Balls of steel and hats off to you 👏 🙌
Very good demo Joon Ive been banging on about how DIY (amateurs) are so casual about dc distribution - but I just a a big yawn from forum members (like Im a party pooper). One thing to note is that an arc can be killed by distance (for a given voltage). Its not possible to sustain an arc at 12vdc from a car battery. Use a 24 v pair and you can do dc welding. But pull the rod away from the work by more than ca 1/2" and the arc goes out. My take is to stay at 24v its much safer. 48v might need a 2" separation (tbc). I believe the very common domestic 63A knife switch (ca $10 us) would do the breaker job very neatly at 24v (48v tbc?). These are all over the far east and solid reliable, as are the Siemens NH style knife fuses ($5us). IMHO there's a massive cartel trying to monopolise the Solar DIY market and its rife with fraudulent parts - fake cable (4mm2 labelled as 6mm2 etc)
Thanks for this Joondalup, but I am confused. At around 4:40 you say the inbuilt breakers are approved to operate under operating current, and then you say that they should not actually be switched off under load because of the strength of the DC current arc. Where then am I supposed to break the current under load, or should I just never turn them off under load? Anyone?
Seen guys put some blankets to panels to reduce voltage/current to 0 before turning on/off. Not sure that approach is sustainable...
Yes good point and sorry for the confusion. I explain better in the next video I am currently doing. If you turn the solar controller or string inverter if ac coupled off first then the current flow will stop. Then it is safe to switch off the dc breaker.
I have used a DC breaker in that style. 1000v 16amps. No issues switching. Obviously that brand you used has simply not be designed to operate at the voltage and current used or it's a faulty design. A DC breaker of that style should follow it's ratings. What brand breaker was that? was it an AC breaker?
In my inverter manual it states, never disconnect under load. I guess the same applies to battery disconnect. Would a disconnect fuse be safer as it is manually disconnected ?
Great video, please make other videos with safety tips as there are a lot of diy solar people out there.
What is the voltage going into the breakers? If one is doing a 24V or 48V system, it should not be so easy for arcing to occur when breaking the circuit, right?
Correct
EE here. I laughed and laughed at the video and the title. Watch me light this pile of hay on fire to prove that hay is a bad idea. So much wrong here, I wouldn't even care to start.
I was laughing too.
@@schrodingerscat7218 A good demonstration though showing what could go wrong.
To be fair, it's a sobering look at what happens if you don't understand what you are doing. It's not like this stuff isn't fully available DIY. I am not really sure how having the isolator IN the inverter solves the issue of wanting to isolate something, but what do I know. The UK have "banned" DC switch isolators on Solar panels in their new wiring guide. I'm going to keep mine. I may be stupid, but I don't see how the individually fused lines won't work. And my ratings aren't for toy voltages and currents either. I'd be nervous if they were on my house roof at this point, not gonna lie.
So what we do if we need to off that pv string under load what type of breaker use?
You dont turn a pv string off under load.
@@joondalupelectricalservice3201 if we need under some situation like short circuit on Ac side so that y i ask i have inverex 12kw inverter which have built in disconect switch on side of inverter
to protect dc load you must use breaker with proper interrupting capacity at that dc voltage and having number required of poles in series as a representative for the correct number
Great demo mate
Would this huge draw trip the 30 amp inline solar fuse I have on each home run connected to each array?
so i have a DC isolater rated for 1000v 63A but i am only running 250v 20A ,,would that one also go to smoke , if i break the circut in high sunlight? i have only turned it off early morning or late night...
Hi. I am now planning to arrange a solar system, and looking into various issues I might run into. :) Yours is a great input, one thing that concerned me, when you were explaining at ~5:30 you take the wire connected to breaker '-' contact and say it is '+'. Is it possible that you changed the polarity, and that is why the arc went not in the extinguishing chamber, but went the opposite way into breaker 'insides'? Thank you
Hi
With these ones no matter if they were wired correctly (positive to negative flow of current) they would still do this. I will do another video soon to better explain.
Is using a higher voltage DC fuse for the holder better in this case than using breakers?
Is a fuse better, more sensitive in this use case, acting as sacraficial?
That jumper doesn't seem right? All the schematics I have looked at show 2 methods on battery side going in. 1324 and or 1234? I am glad I haven't screwed anything up yet. I am waiting on some 4/0 cable and some DC cutoffs. Resetable 300 amp breaker. Lug crimp. Stuff. Everything is so expensive.
Your breaker needs to meet not only current loads as well as break voltages. If your sized correctly, then your over current protection device isn't an over current protection device.
What if there is no load, but only batteries that are being charged. Can you still turn off the isolator while the batteries are being charged? Since the battery is like a load. Or do we need to turn off the breaker for the battery before turning off the isolator for the pv array.
So they are dangerous when you “make” the contacts at high voltage. How do they do when “breaking” contacts when they started closed?
Video is off contacts breaking
Did you try putting a strong magnet near it when you threw the switch ? This may pull the arc away and cause it to extinguish.
Sad we are not sure about polarity of the test connection. Usually power source is connected from the top, and load is down.
Wow, Australia regulations are like years ahead of UK solar regulations.
Go with 1000 Volt inline fuses. When they open a temporary inert gas is given off inside to assure a voltage breakdown will not occur. Way safer than air breakers. DC has no zero crossing so it is harder to remove a breakdown ark.
Great content. Thanks for putting this up.
it's good to be aware of the risks but this video is incomplete and misleading. no info about the breaker ratings, solar open circuit voltage, if the breaker is wired correct polarity, etc. moreover, those extension solar conductors increase the total inductance and therefore the arc energy which may be beyond the breaker can handle.
I like your comment, BUT "inductance" is a AC phenomenon.
Great demonstration!!
Not enough information provided to explain your situation
From the title, the poster doesn't care to inform, just scare you to hire him. Not impressed.
What is the difference between the dead short you created and the internal short inside the breaker as a result of turning off the load?
It wasnt a short internally as such ,but the circuit breakers inability to break the DC arc as contacts opened.
I don't know if you plan on doing a followup on this one since it's now a year old but if you do, do the short circuit test as in this clip, but also show the same model of device interrupting the PV on inverter drawing Imp off the array. It might be eye opening to some of the other people that have posted on this video about their MCBs and how they haven't caught fire ... yet.
Hi and yes absolutely I will. The video raised a LOT of interesting comments so I do want to make it clearer for everyone.
I hope by now you remembered to speak with Todd
I've tested quite a few breakers here in the US under a DC load. 92 volts DC.
Its interesting, because our standard AC breakers like Square D homeline breakers stood up better than the actual DC rated breakers I had. None pf them failed to extinguish the arc. Although the breakers I was using where rated for 5ka but the homelines where rated for 10ka which probably had a loot to do with it.
Would be very interesting to see more breakers tested under DC load, even ones that aren't DC rated since that seems to be a thing that is done a lot too.
Remember the types of breakers out there .The best breakers are thermal sensing ,current sensing and magnetic tripping .Also operating voltage gives it the ability to extinguish and ARC ,Always she's the load in the panel before you open the main breaker .Same thing with fused disconnects protecting panels .Also there are HP ratings to contend with ,not just current and voltage and ratings AIR and most important .NEMA vs IEC .I'll take NEMA every day over any IEC .Just remember if your short circuit current is 10 amps don't put in a 15 amp breaker or fuse for that matter even if the wire is rated for 30 amps ...As the voltage goes up you will need devices with arc chutes for quenching the arc .Some uses several contacts in series for arc quenching
Can you combine a dissconnect switch and a smoke detector? So if there's smoke in your eletric room it will automatically kill the power?
What is de voltage and amp spec of that breaker?
9:50 Don't shut down under the load??? Its a circuit breaker, and supposed to trip under load.
Not in this instance, its purpose is an isolator not circuit breaker. Watch my latest video where I explain a bit better. 👍🏻
Hi there does Growatt inverter has in built isolator
I believe they do these days yes
Perfect explanation.... Thanks.
"dont fuck with these" !!!......as a sparky in the states, i can attest, to the lack of knowledge most of them have. especially with DC voltage/currents. thank you for the show !!
Really I've been hot 🔥 rodin my shit for years, lol , they don't just catch on fire lol , good luck 🤞
Wow, that’s an eye opener!!!
Just use fusels instead breakers for DC and that's it. Of course, you have to be using the correct Amperage and solved. No fires, no problems.
New subscriber. I now no why my breaker failed luckily without fire . May go to a giant Frankenstein knife switch instead. LOL
what is the alternative equipment that you use ? cheers
An appropriate rated DC circuit breaker as shown at the beginning of the video 👍
Thank you for making this video, this is very very helpful, might even save some lives! Just curious, do you think it's safe to say that all Cbreakers with that similar design (possibly rebranded) are equally as bad as this one in the video?
Depends on the application but I wouldn’t trust them beyond say 12volts
superbe test en direct !👌
Noark breakers come in 1000v and 450v. Most inverters are 500v now. So if you mess up and put the small breaker in, which is easily done if you have loads laying around. Magic white smoke.
That went fast, what are the ratings of the breaker?
Actually these so-called dc circuit breakers are not designed for dc at all. A proper dc switch or breaker will be physically a lot larger, have proper arc shields and arcing horns all built in. What is currently used is a re-branded ac breaker. It can still be used with dc, provided you wire up a "snubber" circuit in parallel with the circuit breaker. This should consist of a resistance in series with a decent size capacitor and the arcing problem is solved.
Excellent scary example.
oh my...i plan to install 100w panel so i need highier amphere swiich braker for 100watts d.c output
I'm not a PV installer or even a "spark" but my understanding was that in PV panels the Voltage remains constant and the Current changes due to light conditions. Please be mindful if you reply, I'm a mechanical engineer not electrical!
Except at dwan & dusk, that's broadly correct
Mostly. Only complication is that the open-circuit voltage is a fair bit higher than the optimal operating voltage, so you need to rate your components accordingly. A panel sold as '12V' will usually be able to output 20V under no-load conditions.
@@vylbird8014 22 or more.. 18v at maximum power point. They sold as "12v" panels, because that's the target nominal battery voltage. You need somewhat higher voltage than the battery charge voltage (~14.4v on a nominal 12v battery). Just adding info to your already informative comment, for others.
the dry air has a breakdown voltage of 3kV/milimeter, if the air is wet, this value is lower. if the distance between the contacts is 1 milimeter and there is an arc between them, it means the voltage is already kV. due to the parasitic inductance of all the wires where the current flows in a closed loop system, if you open the loop, the parasitic inductor tries to resist current change and it will increase the voltage creating an arc until all energy of the inductor is dissipated and the voltage returns to that of the PV panel/string. if you want to minimise the arc, keep the wires as short and thicker as possible.
What was voltage of this solar system?
Hi
Around 350v from memory. I will be doing the experiment again soon with more detail.
@@joondalupelectricalservice3201 Why experiment, this is trustable brand dc breaker, its rated for 220V DC so you are more than 150% of its rated voltage. Do you have any education in electrics? or you just try experiments if breakers burn or not?
how much voltage and ampere was on this?
Its in the video but I will do another more detailed one soon 👍🏻
I take it that the polarity was the wrong way round? Please confirm.
That is a polarity conscious isolator but they will still do that regardless if wired correctly or not.
A capacitor in parallel with the panels, and a capacitor in parallel with the load would prevent that. The capacitor voltages would be equalized when the cutout is closed, and would maintain that 0 voltage potential long enough for the contacts to separate enough, that the peak voltage difference cannot cause an arc. The capacitors have to be sized for the current of the panels, and, the separation speed of the contacts in the switch. A knife switch needs large capacitors, a spring loaded breaker can use smaller caps.
The scariest thing about photovoltaic panels is, that if loaded down to ~80% of open circuit voltage, they become a constant current source. Once an arc is established, that arc can be drawn out to several centimeters, depending on the voltage of the string! The breaker shown in this video only has about 5 millimeters of contact separation when open. It will barely even reduce the current transferred to the load.
I don’t see how that would help sorry.
it is a great heads up but the title is a totally stupid approach. You could help a lot of people to address the critical points and demonstrate how to avoid the pitfalls. If you make a series doing just that I would even subscribe. Saying "DYI and Off-grid is a bad idea" will just alienate viewers and for sure nobody who would otherwise be willing to build a solar system by themselves will say "oh this video said it was a bad idea so I will call an installer to charge me an arm and a leg for pointing at a decent isolator". Whoever is up to the challenge (like myself) is totally interested in the possible issues and the right approaches to avoid them but will definitely not be scared by the fact that wrong connections can cause fire - no sane person in the world will assume it is safe to connect electricity the wrong way.
You could and should say everyone should do their homework, research the subject and may guide them to some reliable sources of knowledge. You can absolutely warn viewers that if they screw it up it will burn like this and even worse (you did not even talk about lithium battery fires).
"why DIY solar and Off Grid is a bad idea" - it just looks like a contractor trying to secure more job. Which btw I don't really think you want but it looks very close.
Is that not circuit breaker?
That‘s why i dont use breakers at all. Although i only have 200 watts of solar. I dont know why i would want to disconnect my solar panels? I just remove the cable from the charge controller. Also the voltage isn‘t dangerous in my case
@@batterynerd8779 In an emergency situation perhaps?
@@richardjones3112 whats an emergency? 200w is near to nothing. And my system is not located in the house.
@@batterynerd8779 A fire perhaps.In a domestic household I was thinking.
Well done, is that from solar for wombats.
Moral of the story: Do not disconnect solar when it is under load, whether it is breakers or MC4 connectors.
Surely in an emergency situation a means of quick isolation is essential and can be carried out by a homeowner without specialist knowledge?
@@richardjones3112 As long as you are using a DC breaker that is rated for the load then it is safe to disconnect. But you should never disconnect MC4 connectors when they are under load.
@@BlueSky-cy5nw I agree with you 100% but why would you have an installation that didn’t have the correct isolators fitted in the first place?I can’t get my head around how that could be possible.
@@richardjones3112 It's not intentional. It's just that there are a lot of cheap DC isolators out there that don't meet specifications, or have the proper certifications.
@@BlueSky-cy5nw Ok thanks.I’m an industrial electrician(steel works)btw and we tend to over engineer our installations.
Don’t let this video scare you from going off grid of course a fire will happen if you jump the negative to positive like you did in this video
You missed the point (it happens ;-) ), no fire happened during the short circuit. The fire happened when the short was *disconnected*/opened and the resultant arc was not interrupted . Solar panels can be shorted indefinitely as the cabling is rated for that , and panels can't supply more than that (unlike most batteries). Solar panels can't only supply a limited current to their loads , a short is no different than a heavy load, they will just max out to their Isc amp rating and that's it (voltage will drop). However when you interrupt it under max load.....that what we see in this video.
Isn't this why "No arc"DC breakers are used? .. It's why I used them....
DC isolator or is it DC circuit breaker?
In this application yes its a dc circuit breaker however its being used as an isolator for the pv array. Hope that makes sense.
So what's the solution?
The latest inverters have arc detection and PV disconnect switch.
@@sang3Eta Oh I see, so get rid of all our older inverters and spend thousands on new ones?
@Bushcraft1974 You can fit an external DC switch to your DC in cable. You can also put an arc fault detector in your fuse box. In the UK we also only use serial string inverters with lower Amps higher Volts which also helps eliminate arcing.
The panels don't run at their maximum current, thats directly proportional to the irradiance. They tend to run at maximum voltage. If you add optimisers or micro inverters then the opposite becomes true.
This is why roof top solar requires rapid shutdown devices that will reduce the voltage.
wow
I have done my own offgrid, I used DC rated isolation switches and everything is in a durable metal enclosure, to be fair I have heard of plenty of professionally installed installations catching fire, and the classic stupid mistake is installing inverters in lofts.
This stresses the electronics in hot weather, also people have been known to pile old bed linen and Christmas decorations around these inverters, leading to even greater thermal stress and fires.
Rule of thumb 10kw inverter for every 7kw of demand ..Leaving 3 meters of space around your inverter is essential .Also the same rules apply for the derating of conductors based On ambient temperatures .You drop your ratings if your inverters ambient temperature is at 50°C like in attics and lofts in summer .Derate again for that and you may be only able to run 5 kw on a 10 kw inverter .Adding fans for cooling is essential and fresh air. in many cases the attic temps are much higher than outside .More fans !Or water cooled heat exchangers
Same here, I did my own and it's been working great. Why scare people away from solar? Isn't an unreliable power grid more alarming?
@@scottwilliams5196 there is no such thing as free energy or green energy .This is the problem going from a reliable power source to one that is not .Solar has its uses so long as you have the ability and space to provide more power than what you need and the ability to store enough surplus to operate for 1 to 2 weeks .Let's face it we have many cloudy and overcast days and at times for weeks in a row .It's not a reliable power source but a means of augmenting a power system .All you are doing is off setting the carbon foot print to a later date .They are highly toxic ,have a relatively short life span in some locations and have issues with maintenance and need to be cleaned to keep efficiency up .I like solar,don't get me wrong but it has its issues and has limitations and they do harm the environment from manufacturing ,disposal and the change in temperature in the area they operate .So do wind mills ,they kill wild life and redirect air flow and introduce noise that can be harmful to animals and humans .Basic laws of physics
.(Energy Can't be Created, Only Transformed From One Form To Another )And that's that !You can't get something for nothing .Everything has a cost
@@carlubambi5541 my tool box has many tools. I don't reject a tool because it can't do everything. Solar has been a great tool for me. Wind would be a good tool as well. Grid is a good tool. My panels will long outlast me and probably the next person that comes along. I replace batteries in my solar like I do in my cars, truck, mower, generator and power tools. We all do that. Not complicated. If you don't want alternative power, cool for you. Enjoy that choice, but don't dump on others who try to think outside the box.
@@scottwilliams5196 yes I agree it has many uses ,it's a tool like anything else .It's has its uses and limitations,and should not be promoted as a be all and end all and cure for an imaginary enemy nor as a cure to solve an energy problem that does not exists .You see the more energy is produced the cheaper the price ,the problem becomes at what point will it be profitable for the produces .Eh Pickering nuclear plant produced electricity at a cost of 4 cents per Kwhr over its life span .This cost includes the building and maintenance .Distribution is another head ache and cost .The end user was paying about 6 to 8 cents per kWhr .they now privatized electricity and now we are paying as much as 10 times .for the same electricity .We are paying between 50 to 80 cents per KWHr for solar and Wind .!Something is seriously wrong .
If I had the space I could put in about 4 kw of solar .The cost would be too high and the recovery too long 20 to 30 years before you break even .I have 400 watts on my shed to charge my tools and lawn mower and supply security lighting .It would cost me $3k + to run a wire from my house to the shed .So I spent$1500 for a stand alone solar system .The batteries are the biggest cost at almost $400 each .I use 2 RV marine lead acid batteries and a 1500w inverter .That's more than enough for a stand alone power system .When the power does go out I use a back up generator .
its a dead short circuit??
Yes and no, thats how solar panels function.
You know it’s wired not correctly - it clearly failed on right one that was done in reverse and of course overcurrent device should break under load… so that statement is absurd - not sure what is Your intent since You know that because You mentioned there are non polarised one that I use. So case is there is no lack of knowledge on your end - there is another motive - wondering what?! Can you explain motive?
16 amps DC is kinda small… 🤷♂️. Seems to me they should have never been used for the application.
Non Polirised MCB? ASs this is an Polirised MCB