Solar Upgrade EP5 - Fuses or Breakers?

OK, OK, OK, this is the final video before we actually upgrade our solar. I made the last few videos while I was waiting for parts. It also rained a lot over Easter, so a good excuse not to be on the roof.
So, the question is, should you use fuses or breakers for your solar system. I came up with 3 good reasons to use a breaker. Do you have more? Leave them down below.
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DISCLAIMER
By watching the video, you agree:
All electrical work must be carried out as per your local laws, rules and regulations. Installations and setups shown in my videos are for test and demonstration purposes only and may not satisfy regulatory requirements. Installation are temporary, for the above purpose and for making these videos. Most electrical work is not for DIY purpose and must be conducted by a trained and qualified person. Please always check your local regulations!
Any liability for conducting your own work, in particular, any consequential damages arising therefrom, shall be excluded.

[@JohnMarkMaina]

You forgot your signature phrase "It's 0 amps outside" :)

[@jmaus2k]

The voltage is from the moonlight. Very low amps, but it is something.

[@unliyou]

What the heck! hahaha You always bring something new every time. You always bring joy, it does not matter if there is a problem or not, there is always joy in every video and make my face smile - big smile. Thank you. Yes, circuit breakers are better and not wasteful than fuse when triggered. For lightning, SPD or the surge protection device is there for that and is connected to earth ground when triggered.

[@OffGridGarageAustralia]

Thank you 😊

[@richardowens9061]

Remember, fuses and circuit breakers have ONE purpose - to protect the WIRING. If the need is to interrupt a circuit, a simple SWITCH will suffice. And, as others have already pointed out, ONE circuit breaker will suffice for each solar array - on either the positive or the negative, but not both.

[@peterpetersen6024]

Technically speaking: To open a circuit under current-load (like the MC4-plugs, or the old fuse-holder), you always need a CURRENT-Breaker, regardless if it's also a fuse in one device. So from now on, you can safely open the PV-circuit even at noon. The old fuse-holders were not built to do that, nor the MC4-plugs are.

[@szevlin]

On the clamp meter you were reading millivolts not volts so its possible they were producing 2 millivolts at night, and also you could enable the backlight so you could see better :) Awesome video as always

[@OffGridGarageAustralia]

You are correct. It was too dark to see that 😂

[@lyfandeth]

As a practical matter, you've got a much better chance of getting hit by lightning, than of ever finding 11AWG wiring. At least in the US, the home of AWG.

[@kiello26]

That was milli voltage. :) your ammeter also has backlight. Thanks for the videos

[@OffGridGarageAustralia]

I forgot about the back light...

[@amudlifecrisis]

It was 50 amps out today in Rhode Island. My batteries were topped off by noon! Great video as always. Thanks for all your hard work making these.

[@OffGridGarageAustralia]

That is awesome! Thank you.

[@jamesdk5417]

I have heard from other KZbinrs that specialise with electrical gear that most circuit breakers are not built to handle many operations of being switched on and off many times and can lead to premature failure. I am not an electrician, just have watched many hundreds of hours from Chanel’s that specialise in electrical. Thanks again for another entertaining episode.

[@antoni_sk]

A good decision with replacement (although not necessary). I'm looking forward to another video again. :-)

[@OffGridGarageAustralia]

Thanks for your regular comments, Antonin. Much appreciated 😉

[@cowboymcq6711]

Your videos are very informative and fun at the same time keep up the great work buddy ❕❕❕❕

[@tabineshhtc]

Great video as always.

[@solarute5486]

Both breakers and Fuses have their place. Those fuse(holder) make a very convenient isolation switch. Given that solar panels have a maximum current (and voltage is just about a 100Volts) I would have just left the fuse holders there. Battery and inverter circuits are a different thing.

[@eat333]

Nice to hear you explain about the fuses. If you have time and the money. I recommend you to shange cable, so rhe color I right. ( I am a automation teacher) you now. Love the videos

[@craigivas4037]

Great decision Andy. Only change I would make is to colour the breakers red and black to help with wiring installation. Still excellent video keep it up.

[@OffGridGarageAustralia]

I'll put some labels on the breakers. Thank you.

[@jamieharland9080]

Putting the fun into power systems is good! too many serious people that are too picky and pick the crap out of everything, I find on KZbin! everyone is an engineer and have to tell you in the comments! keep up the entertainment! and the humour

[@PatricksDIY]

Another great video, keep em coming. Its funny you say you talk to much, to me its not talking to much when you are explaining something at more than just a high-level, when you break things down, it makes sense that you would be doing a bit more talking. I don't know about the rest but I enjoy the in depth conversations that you bring ☺

[@OffGridGarageAustralia]

Thank you Patrick, I'm glad to hear that 😊

[@Shep5847]

The Moon!!! I have seen in few instances when using high voltage strings of panels that moonlight (which is reflected sunlight) can actually be picked up by high voltage panel strings and produce power. I’ve seen as much as about 8 watts at night during a full moon on a 3kw system. Also those orange street lights can also turn on the panels.

[@williammorton3335]

Thanks we have a boat and fitted the type of brakers shown. We normally use 12 volt planet. But had to have next day delivery to one of those boxes at a petrol station. I will be changing them for 12v planet ones.

[@nzhillbilly6468]

Awesome video, love the captions :-))

[@OffGridGarageAustralia]

Thanks! 😃

[@s.emmanuelwillie3559]

Thanks again very much for the help you giving us as a electric student, but I m really interested to work with you in Liberia.

[@vicamaral]

Keep on talking mate, learning a lot from you bimetal sucks breaker better and can be reset, your brilliant, got👍 a new SUBSCRIBER.

[@ykchowaa]

For lighting protection I think either a good ground and some electronic device for higher voltage drop

[@jmaus2k]

You doubled up wire from charge controller to breaker. Most codes say to run only one wire and that it is sized to carry more than 25A. You don't depend on wires sharing load equally. Solar panel leads can be tied together like that with just two wires, but if you had 3 or more each string needs it's own fuse.

[@RikHaanen]

Thanks i was wondering about that to, you answer seems logical. 2 parallel can go in one fuse but if there are more, each needs its own fuse. Thanks

[@MiguelSilva-mb6mb]

I would leave the fuses combined with the breaker. Also I would add a overvoltage discharge in the PV circuit

[@dustyrhoads3857]

Hey @Andy! I had an idea, might not like it because you'll need to redo some wire, BUT you would possibly move the first CC up almost butting the end of the wires from the new breakers at the top. Then you should be able to have nice spacing all the way down for 3x CC's. Just a thought! Let me know what you think!

[@TheComputerGuyDR]

I concur!

[@awesomusmaximus3766]

Don't worry the CC does back feed some voltage back to the solar cells when it's resting it's perfectly normal

[@neliosamch3195]

I prefer breakers and controllers for each arrays for troubleshooting, convenience and to keep an eye on the condition of production and cleanliness of them.

[@OffGridGarageAustralia]

Fair enough!

[@neliosamch3195]

@@OffGridGarageAustralia How you protect your system against lightning? I don't have one because not too many thunderstorms in my location and nearby high power lines protect my system indirectly.

[@SolarAddict06]

I think you should also install a dc surge protection device parallel to the pv dc breaker....

[@peterevenhuis2663]

Yes I agree, I did the same and in my case during a big lightening storm , ones it already tripped protecting my charger and inverter.

[@DutchAussieProductions]

Thanks for another great video. One question. Why do you use black wires for power cables? You seem to have plenty of red wire on that roll you showed before.

[@stoptheirlies]

Hi Excellent video's thanks, is it possible to use 10 or 20 amd circuit breakers instead of those din rail fuse holders you have?

[@mindovermatter3988]

Your multimeter is yelling at you 😂

[@danfitzpatrick4112]

Hahaha! I remember connecting an electric panel up when cell phones first came out years ago and right when I went to terminate a wire on a breaker my cell phone vibrated! Man, I thought I was a dead man.. My screwdriver went across the room! LMAO

[@OffGridGarageAustralia]

Hahaha, it is a really scary moment, right?!

[@AGhostInTheMachine]

My DMM auto-off seems to always beep at that moment.

[@PeterMilanovski]

It's a common misconception that solar panels don't work at night or when covered by snow but that's not true! Night time energy capture all depends on how big the moon is in the night sky and angle. Some nights you will get more voltage than others... But the biggest surprise is how panels perform covered in snow ❄️.. for some reason it's like they aren't even covered in snow... There's a great video that someone did about this particular topic...

[@MrSummitville]

Contrary to what you claim, "... for some reason it's like they aren't even covered in snow ..." In the REAL WORLD - Snow covered Solar Panels produce significantly less watts, and if the voltage is too low (under load) they will produce 0 Watts. Also, at night, Solar Panels does not produce any usable watts.

[@kevinh7985]

Thanks Andy, another very informative and entertaining video. Please continue the level of dialogue it’s an effective aspect of your videos. I will be applying many of the learnings as I continue with my project. Cheers Kevin

[@OffGridGarageAustralia]

Thanks, will do!

[@jmaus2k]

Many will say circuit breakers are less accurate and it is more chance of getting a bad one that trips too easily or doesn't trip than a bad fuse. But whatever the case, either work about the same. Happy you increased from the 10A fuses....since these were undersized. 25A per 2 strings now should be ok. A circuit breaker can trip with a high inrush current because it has a magnetic trip system in addition to the heated metal part that trips, which would be similar to a fuse. If you have a lightning strike....you are replacing things. 100V rating is nothing when 100,000V lightning bolt is coming. You will never have a fuse blow if it is sized correctly, so ignore any comments about saving costs because you won't have to replace fuses.

[@OffGridGarageAustralia]

Thank you.

[@user-ys9ym7rd3u]

crazy what have happend in 2 years of time ;-)

[@ianstanley5157]

Maybe use slotted trunking to tidy up the wiring?

[@anatoliyovdiy6466]

Hi. Maybe I missed it, but you are not using regular AC circuit brakers are you? For DC current you need to use DC circuit breakers, on full load the regular AC breaker can still be tripped by the thermal protection, however it can have an arc formed inside for quite a while, leading to bad stuff. DC circuit breakers have special 'features' like enlarged arc extinguishing chambers etc. I admire you doing all you are doing and sharing it with us, and you saved me from making quite a few mistakes I was about to make with solar. :)

[@sreekumarUSA]

071721/0434h PST 🇺🇸. 071721/2134h Brisbane 🇦🇺 Thank you for the presentation. I’m watching your older presentations now, that’s all. They are educative, as always. They are not ‘old’. I’m using DC CBs throughout the systems. 2 for PV Cells inputs, 2 for VICTRON BMS OP to LiFePo4, 2 from LiFePo4 to VICTRON inverter and 2 AC CBs to inverter OP to loads.The only difference is Fuses act instantaneous and the CBs with a slight delay. I tested the actions of both CBs and fuses and found both to trip/fuse simultaneously. Thanks again and please keep, up the research. Stay safe and 73s…

[@billallen275]

Nice. You could have thermoelectric effects going on, if the air is cool enough and the ground is warm. ? Of a big moon??

[@enterthelegions]

Beat is to use fuses and breakers in series to get best of both worlds

[@jameshoff9435]

We are installing an array (425vdc at 10 amps per string, 4-strings) Where do we locate 500vdc breakers at 20a at a resealable cost to install in the combiner box? Will to install 2 combiner boxes if need be.

[@notaperson3338]

Great video and presentation style. Something to consider, circuit breakers are only warranted for one trip, after that there is no warranty. Many do not know about this but check your warranty card please. Being a electro/mechanical device they can malfunction, a fuse is very simple and reliable and also only does one trip, however what is your property worth to you? This how I would measure what I would use.

[@OffGridGarageAustralia]

Hmmm, never seen that anywhere written. It says something like 10000 disconnects or so but that could be just the manual disconnect not a fault trip.

[@greenmenpt]

any solution to precharge when we turn on bms the cap of inverters ?

[@RikHaanen]

Andi, did you not explain in an other video that if panels are in parallel, you must fuse each paralel part. Because if one shorts all power of the others will run trough it. Now you just undid that safty measure. The diode test is interesting, but does it not confuse this safe issue?

[@sumojasmj5368]

I would leave the fuse in the circuit as an extra protection as I have seen a CB melt and catch fire with the contacts fused on.

[@OffGridGarageAustralia]

I have now inline fuses with each string of solar panels on the roof and one main MCB inside the cabinet to turn them all of at once. This needs actually upgrading as I have far more solar but never upgraded the MCB. Another project on my list...

[@mickeylewis8094]

For protection a fuse is much better. A circuit will wait to see if it's a short, overload, or a ground, before it trips. Meanwhile a fire could start by then. A fuse on the other hand, doesn't wait to see what's going on, it trips immediately expect if it's a time delay fuse.

[@herblapp6134]

I don't believe this about differences between a fuse and circuit breaker. I don't believe this is true about time delay in the ckt bkr compared to a fuse. In college in the 60s l worked at ITE Circuit Breaker company in Philadelphia. After being there awhile l asked what ITE stood for. It's the abbreviation for INVERSE TIMING ELEMENT. It's possible ITE was the inventor of this important internal equipment safety device (that's my hunch on the inventor). ITE made breakers for the US Navy. I assembled an internal breaker component called an arc shoot assembly. Which is in our AC and DC breakers being shown in the video. Simply it is a series of parallel plates spaced abt 1/16 or 32nd" apart like plates in a capacitor. It's made up many individual metal plates whose purpose was to quench the powerful electrical spark created as the contacts quickly separated breaking the circuit. The plate's stamped shape was similar to a horseshoe where the contact arms were allowed free passage to open and close. The heat generated by the arc could easily melt welding the contacts together preventing them to separate. In normal opening of a breaker when the circuit is live creates very intense small arcs which pit via melting slowly destroying the contact's surface, hence requiring the need for more frequent replacement. Navy contacts were silver plated to reduce surface resistance. The energy absorbed by the assembly went to ground. Hence preventing contact pitting damage or worse being welded together. The DC breaker seen in our video had two independent methods of breaking the circuit on overload. A bimetal trip arm that when heated released one contact arm held by a locking mechanism. The bimetal's properties were designed to open at a certain temperature. It allowed more current to be passed beyond the trip temperature allowing motor inrush current (approx. 6 times normal running current to safely pass for the extra tenths of a sec it flowed until the current fell to its running current. This prevents nuisance trips. In the event of a dead short in the external circuit the electrical cable had to be protected from this continuous excessive current draw that can cause fires.The beauty of the arc shoot assembly et. al. was one breaker arm was electrically connected to an electromagnet. It's response time to open in microseconds immediate to the short. The strength of magnetic field created is directly proportional to the amount of current flowing in the coil which was the same as in the external circuit. So modern breakers differ from the common fuse in it has one trip mechanism that avoids trips caused when motors normally startup. If that inrush current continues to be drawn then the bimetal arm continues to be heated to the point where the contacts open the circuit. But in the event of a catastrophic short the bimetal's slower reaction time doesn't prevent cable-equipment damage. The electromagnet magnet's reaction time to trip is inversely proportional to the much greater current drawn from an electrical short.[

[@johnlazdins2004]

Hey Andy I was told to not disconnect PV cables or mc4 while under load,,?

[@kevinroberts781]

On a commercial solar farm the moon light produces enough voltage/power to kill a person. Just a fun fact.

[@OffGridGarageAustralia]

I measured like 5V at one clear night in moonlight. Enough to charge a phone 😉

[@patrickgeers1]

I like you videos I am new in solar stuff It's so many to now Strings volt amp battery and more 🤣 Everytime when i watching a video from you I lear something Thanks keep going 😉

[@jamess1787]

Nothing protects against lightning. Overkill sub-1 ohm Grounding is your best bet, but then you're inviting the boogeyman in. (Just make sure you're the smaller structure in the area with good ground potential and sacrificial ground pole :D)

[@jamess1787]

"Completely about circuit breakers" Yes.. Yes... Of course!

[@user-bi3ic7ny3c]

Is a 220 volt fuse suitable for the solar system?

[@ykchowaa]

I prefer fuse and switch as fuse burn very fast to protect the system. But circuit breaker either the current jump very quick or overload from sometime as most the circuit breaker has c cure that told too long to trip

[@felaxchow207]

Fuses or breakers dilemma. I go with breakers for the reason if it is rated for DC applications, they can be disconnected under load while fuse holders are not really designed for that and have a potential of arc flashing when breaking the circuit under load. There are some disagreement about breakers being used as a regular DC rated switch depends on the manufacturer if they rate them to be switching duty or not. I have the same dilemma since my system on net metering and if I take it down during the day will cost me in generating credits. Most of my upgrades or changes to my system has to be done in the evenings unless I don’t have a choice in the matter.

[@MultiOutdoorman]

MCB is resettable too ... no need to keep spare fuses !

[@anuarabdulsamad2688]

Put a DC SPD for surge protection..

[@jws3925]

Once again, why do you need a breaker for both the positive and negative? Wouldn't interrupting either, but preferably the positive, break the circuit? Secondly, could you show how you combined the cables to fit into the new breakers? You called them something along the lines of boot laces whatever they are. What kind of ends (the ends going into the breaker) are on these wires. I'd be interested. Thanks

[@MarkusIngalsuo]

This seems common in solar, if breakers are used, and I'd guess it has to do with lightning safety. The panels often reside on the roof and are exposed to atmospherical phenomena, so, having a breaker on both wires will give you a disconnection for both wires.

[@sergeyblinov4957]

Interruption of both wires in miniature (modular) circuit breakers, MCB (I assume a DIN-rail mounted MCB) is also needs, as only 1 pole is generally not sufficient for interrupting DC current with reliable extinguishing of DC current's arc between MCB's contacts. Even in special DC version of more common AC type MCB.

[@bennjanse]

Do you have a slight hum on the invergter when in operation ? Kind regards Ben ZA

[@OffGridGarageAustralia]

Only if these fluorescents lights are on.

[@ciprianalexandru7369]

What if u use the fuse and the circuit braker?

[@marcosmercado5648]

Watch out!!! Something jump near your back at 2:34!!! :-) Anyway good video!!!

[@neliosamch3195]

Ausy mosquitoes are that big?

[@marcosmercado5648]

@@neliosamch3195 That explains why those frogs are so many and healthy!!!

[@OffGridGarageAustralia]

Just a moth attracted by the bright video light.

[@SpeakerKevin]

Must be a FULL MOON.

[@vaneay]

Power from the moon :P

[@dusank3806]

Great video (as always).How are you protect your system against lightning?

[@MrSummitville]

Protect? Reduce the damage, maybe ...

[@Wayoutthere]

Best thing you can do with severe lighting is still to simply yank out all appliances.. Linting is so overpowering not much (affordable) will save you.

[@bongalzate8612]

good day dear sir......been following you ever since you started. your experiments and all sorts of things makes my spider sense tingling.........i just want to request you try to over power your panels above the recomended wattage by the scc on paper. I know solar panels are not that efficient I just want to know how much tolerance can a charge controller take. will it actually handle the amperage they are rated for? i've tried overpowering my epsolar 20 amps tracer a series. they did well but i don't have those meters and all tools to measure and my panels are old(way back 2009 when they costs much more than my lithium batts now a days). but they did well as per my capabilities. a full test from you will be fun to watch.

[@Nic7320]

Using individual breakers on each individual string has a big benefit when diagnosing yield problems. Some days, when it seems like I should get more yield, I switch off one string and compare it to the other. If the 1:1 (or 2:1 like my 600 Watt:300 Watt system) ratio isn't about the same, then there's a problem. I've found a burned out bypass diode and a damaged MC4 this way. If you don't have anything to compare to, how do you know you have a problem?

[@OffGridGarageAustralia]

Yes, that's what I do as well if I believe something is not working correctly. We will have these fuses on all strings eventually to run more experiments.

[@dffghuytfvb]

on the DC, obviously, a breaker seems more appropriate, but I wonder if an electrical differential would not be safer, actually.

[@OffGridGarageAustralia]

They would not work with DC though.

[@ianjaeger4178]

Back feeding to panels

[@MarkusIngalsuo]

Those fuses and holders are not designed for breaking the current with the contact points in the holder. They arc a little every time and the contacts erode. MCB's on the other hand have built in arc-extinguishing and are designed to break the current at will, up to a promised amount of times. The fuses can help with lightning strikes in combination with MCB's as they may have a higher maximum current breaking capacity than the MCB's.

[@jungleking7197]

Dose any one have any experience with the VICTRON RS 48 6000 smart inverter any thoughts on it ?

[@jonathanposerio3137]

If I may ask, I have 2 120w panel (same brand) the wire of the 1st panel is silver but the other on is copper which makes the current different from each other the silver reads 7.3 amps but the other one is 6.3 amps. I have them in parallel but combining them makes the current only 9.8 amps. How can I solve this issue?

[@OffGridGarageAustralia]

The wires are not the problem, one is tinned copper and the other one is bare copper. The overall current depends what solar charge controller and battery you have, how it is connected and what the state of charge of your battery is.

[@jonathanposerio3137]

@@OffGridGarageAustralia i recently bought a new charge controller. I'm trying to purchase a mppt controller then I've found this brand called perfect suitor which turns out not mppt. I chose the 70a unit because I'm planning to add more panels and battery in the future. I really can't afford to buy another one. Do you think putting a blocking diode on each panel would give me better current output?

[@mindovermatter3988]

You have somewhere locally or at least in your country that will give you free solar Panels brackets and Hardware? I wish I had a place like that

[@OffGridGarageAustralia]

Almost free, yes. People are upgrading their smaller systems now to larger ones and sell the old system for $100-$500, panels, inverter, rails, clamps,... Just sourcing some new panels already for stage 3 and 4 😉

[@mindovermatter3988]

@@OffGridGarageAustralia well that's great and it seems like a good place to get a good deal and meet some good people. I'm looking forward to see your stage 3 and 4

[@daniilvolkov8790]

My question is: Why use fuses at all? It seems, that circuit breakers are better in every way. They don't seem that expensive either for the convenience of not having to replace it.

[@OffGridGarageAustralia]

Ah, they are not better in every way. Fuses have some unique trigger point which cannot be achieved with breakers. I can pull 20-30% more current from a breaker for quite a while without tripping it. A fuse will just blow. So such an effect and behaviour can be desired or not, depending on your application.

[@sami44411j]

Why not keep the fuses and just add disconnectors / isolator switch before your fuses and after the mptt ?

[@georgef7754]

Hi. Which model Uni-T multimeter are you using. Thanks.

[@OffGridGarageAustralia]

This one here: off-grid-garage.com/measurement-tools-and-analisers/

[@georgef7754]

@@OffGridGarageAustralia Thank you.

[@jamest.5001]

Heck , fuse the breakers, the the breakers can be used as disconnects!

[@robbie9170]

Hi< Just wundering, I have got 15 panels in one string. The specs say: Max current 11.7 Amp, and Short Cirquit current 12.4 amp. Does a breaker make sense? Can the total current exceed 12.4 amps? Would a normal switch be better?

[@OffGridGarageAustralia]

You definitely want some sort of safety device, not just a switch. Have a look at the panels what the maximum reverse current or max fuse current is. You breaker or fuse cannot exceed that value.

[@robbie9170]

@@OffGridGarageAustralia istn that the same as the Short Circuit Current-ISC (A) ? That is 12.41 Amps.

[@leonclose7823]

Hey Andy, I would be interested to hear a little bit about the legality and relevant regulations for building systems like this in Australia. What sort of qualifications does one need? I wonder how far a well-informed amateur can go.

[@MrSummitville]

This is all off-grid. Grid-Tie would be very different..

[@leonclose7823]

@@MrSummitville Agreed, But I still don't know if a non-sparky can play with 230V AC or even the DC side above some arbitrary threshold.

[@MrSummitville]

@@leonclose7823 In Australia there are a few areas that are "No Permit Required" zones. You must check with your local authority having jurisdiction regarding permits and/or DIY. In some location, DIY is not allowed because a licensed installer is required. Some of the 2020 *Australian* *Standards* (AS) that apply to solar and low voltage electrical installations... AS 1170 - Wind Loads AS 1768 - Lightning Protection AS 3000 - Electrical Wiring Rules AS 4086 - Secondary batteries for SPS AS 4509 - Stand-Alone Power Systems . . . Part 1 Safety Requirements . . . Part 2 Design Guidelines . . . Part 3 Installation and Maintenance AS 5033 - Installation of photovoltaic (PV) arrays

[@leonclose7823]

@@MrSummitville Thanks for the details. It's a shame that just to read those standards would cost an amateur $1k or so. When you say a local authority, do you mean a council or an electrical supply authority?

[@morrismaneae3634]

Circuit u put in a dc breaker or Ac breakers

[@OffGridGarageAustralia]

They are all DC breakers.

[@Sylvan_dB]

Moonlight :)

[@williamjamesenkerwitz9495]

So Andy just wondering do you ever sleep you always so busy from South Africa

[@teardowndan5364]

By far the biggest reason to use breakers instead of fuses is so you don't get the itch to just up-size a fuse that keeps blowing, one of the main reasons for house fires. My own parents replaced the living room 15A fuse with a 20A one because the AC kept blowing fuses. Thankfully, nothing bad happened and the fuse box got upgraded to breakers 23 years ago.

[@OffGridGarageAustralia]

Great point, Dan! That's a dangerous thing to do.

[@edmundomazenga2873]

Hi andy , my name is Edmundo . I really appreciate your videos , they're very useful, I learned a lot. i wonder if i can have your contact for further information about.

[@OffGridGarageAustralia]

Hello Edmundo, thanks for your kind comment. Unfortunately, I don't have the time to do any consulting, so please leave any questions here in the comment section. Thanks

[@edmundomazenga2873]

That's fine andy. I wanted to get a remote assitance from you . But either way thanks again for replying

[@zaccot.7025]

I prefer fuses, the contact surface is larger.

[@waynehobbs5175]

Great video Andy. Would you sell me the 4 fused switches please? Happy to pay what you ask plus postage. Want to use in my caravan as running 2 diifferent kinds of solar panels.

[@OffGridGarageAustralia]

I will re-use them soon for the solar strings...

[@65bigfalconable]

Hey Andy... can you explain why you went to a high voltage instead of higher Amps ... sorry if this is a silly question...

[@OffGridGarageAustralia]

You mean for the breaker?

[@65bigfalconable]

My apologies.... i mean with the solar panels, I did reply to an older video.... but I realise your super popular now... and can't expect you to see all the replies... so I appreciate your reply and time ..

[@nigelcharles511]

Higher voltage (ie panels in series) reduces power loss in the PV wiring and reduces the cable size required between the PV array and the charge controller.

[@65bigfalconable]

@@nigelcharles511 Thanks ... I was aware of that... is there any benefit from having higher volts then Amp going into the controller for a 12v system

[@nigelcharles511]

The lower the voltage the greater the cable loss for a given cable size so this is even more relevant for a 12v system. In some cases the round trip cable length between the PV to the controller can be many metres so losses can become significant. However as the voltage is less at the controller output, it is always better to mount the controller nearer to the battery than the PV array.

[@junkerzn7312]

Getting miscellaneous voltages from disconnected things is not uncommon. There is voltage all around you, from the ground to the sky. For example, from the ground to the air there is around 100 volts per meter of height. Yes, I kid you not. There will also be voltage differentials between different points on the ground, so a large straddling structure with a ground rod on one side might show a voltage on the other relative to ground. And yes, solar panels at night can generate a voltage too. You can't get any appreciable current out of these sources, but they are there. -Matt

[@mightystreaming933]

breakers are best..you should of kept 4....ever hear one is none two is one. you almost had it right this time :)

[@geroldgoerke5729]

Everything you say about Breakers being better than Fuses, I agree. But the question is: Do you need them in the first place? As your cabels to the solar panels should be strong enough to withstand the short circuit current of the modules (strings) in anyway. I would recommend a switch in anyway so you can also use a breaker or a fuse with breaking capabilities like you had bevor. ;-.) Und auf Deutsch, weil ich nicht weiß, wie verständlich mein Englisch ist: Die Verkabelung zu deinen Modulen sollte sowieso dermaßen ausgelegt sein, dass diese über den Kurzschlussstrom der Module (oder Strings) 'lachen'. Deshalb ist eine Sicherung nicht notwendig. Ein Schalter ist aber sehr empfehlenswert. ;-) Da deine bisherigen Sicherungen aber auch als Schalter verwendet werden können (und auch 'dürfen' laut Hersteller) waren diese völlig ausreichend. Eventuell kannst du sie bei weiteren Projekten verwenden. Falsch sind sie jedenfalls nicht. :-) Danke für deine informativen und gleichsam unterhaltsamen Videos.

[@MrSummitville]

What happens when you have four (4) PV Arrays in parallel and there is short circuit in the wiring in one PV Array? Now you have FOUR TIMES the max allowed current flowing through the short circuit = potential fire. The PV Array with the short-circuit will blow its fuse or open the CB ...

[@geroldgoerke5729]

@@MrSummitville A 2,5mm² cable is able to carry 32A of current if used correctly. Yes there may be constellations where fusing might be necessary but in that cases every string has to have it's own fuse (or diode). Let's say it this way: If there are more than 4 modules (or strings) in parallel, fuses or diodes may be needed.

[@MrSummitville]

@@geroldgoerke5729 Our electrical code is ... If more than two strings is parallel, then each string is *REQUIRED* to have its own OCD ...

[@geroldgoerke5729]

@@MrSummitville That's fine. Better safe than sorry. But one can easily calculate if any fuses are necessary or not. Let's take the last video Adrian has posted as an example: He puts three strings in parallel. Each String has an SCC of 5.61A. That is 16.83A in total. Even if using 2.5mm² cables, there is no risk of damaging or lighting up that cables in case of an short circuit. (Plus, I guess this modules have 4mm² cables and he uses 4mm² cables further on) But anyways: If there are rules or regulations on that topic in your country: Sure follow them

[@rudigerrichter1443]

Good decision, fuses are getting hot, I had a cade in 10KW system where the fuses did melt the Phönix holders even the rating was max. 70% of the current. I removed all, no more problems as the cable cross section was much bigger than the highest possible current

[@benjones8977]

I guess I don’t understand the way you set things up. In the US you’re supposed to have fuses at your branch connections on your solar panels. I parallel two strings of four series panels. So I would need two positive fuses. Then I would have breakers just above the charge controllers and then fuses below the breakers heading towards the charge controllers. At least this was the way it was told to me in the US. But again I am no expert! Then from the charge controllers to the bus bars I would have another fuse on the positive wire to the batteries. Then from the bus bar positive to the battery shut off switch I would have another fuse. So many fuses? 🤔

[@voxpopneverdies2025]

Isolation switch from the roof.

[@paial]

Solar panels are a finite source of power, that can be even shorted (aka the Isc, or the current in short circuit, displayed on the datasheet) to no harm. So there is no real reason to "protect" anything in there. As long as the cable run from the pannels to the controller has been dimensioned correctly, there is literally nothing to protect. With that said, it is convinient to have a On/Off SWITCH (properly sized, of course) between the pannels and the controller so one can work in the controller without going into the roof and covering/disconnecting every pannel. Although a circuit breaker is not meant to be used as a switch (it is simply not mechanically designed/tested to endure thousands of on/off operations as a light switch) it can be used as one for sporadic use.

[@OffGridGarageAustralia]

Yes, I agree!

[@MrSummitville]

@paial - What happens when you have four (4) PV Arrays in parallel and there is short circuit in the wiring in one PV Array? Now you have FOUR TIMES the max allowed current flowing through the short circuit = potential fire. The PV Array with the short-circuit will blow its fuse or open the CB ...

[@paial]

@@MrSummitville first you should be considering installing them with either a separate controller each (string) OR all in series (if partial shading is not a problem) with a high voltage (input) controller. it is just NOT good practice to keep paralleling arrays like that. Victron, for instance, have off grid controllers all the way up to 450v input (others, more, and the pannels are normally rated for 1000v or 1500v). And for partial shading, you be always better off with separate controllers. In sailboats (very prone to partial shading from the mast(s) and rigging) I have done many installs with one controller per pannel or couple of pannels. But if you are going that route (of paralleling many strings), yes, you might, have protection for a catastrophic event (decent pannels do not just "short out" out of the blue).

[@sami44411j]

Isn't it better then to keep the fuses and simply add disconnectors / isolator switch before your fuses and after the mptt for isolate the mptt ?

[@theonlywoody2shoes]

Third benefit of breakers vs fuses is that you can easily see if anything has tripped - and a 4th is that you don’t need to purchase/hold spare fuses should anything fail. I’ve seen a few watts of production from a really bright full moon, and as for lightning flashes at night⚡️⚡️⚡️🤯🤯🤯

[@OffGridGarageAustralia]

Thanks, Ian.

[@laus9953]

machst dir ne rübe daß die schwatten drähte ein paar millimeter unterschiedlich lang sind jetzt.. aber dein datenkabel hängt wie ne wäscheleine in der luft.. mach liber plus und minus verschiedene farben wenn dir details wichtig sind (das "u" in "circUit" wird übrigens nicht ausgesprochen.)

[@teror1sta]

What is the point of CB or fuse ? For example your panels are to say 8A at 38V x2 = 16A . If you short this panels max current is to say 9A x 2 = 18A . So .... even if your charger burns out and short everything you can't reach 20A and anyway MC or fuse will not shut down ...

[@MrSummitville]

What happens when you have four (4) PV Arrays in parallel and there is short circuit in the wiring in one PV Array? Now you have FOUR TIMES the max allowed current flowing through the short circuit = potential fire. The PV Array with the short-circuit will blow its fuse or open the CB ...

[@teror1sta]

@@MrSummitville Do you thing so ? Did you try to think first before write ? To say you have 4 parallel PV with 8.66A PMAX = 34.64A you MUST have 40A CB/FUSE . This panels at short makes 9.13A = 36.52A AND ????? STILL LESS THEN 40 A = no CB/FUSE engage ..... Pls do not answer me . I know the answer of my question: it is pointless to put CB or FUSE . If you are too smart put 10 CB and be happy .

[@MrSummitville]

@@teror1sta No, you have NO CLUE what you are talking about. *EACH* string must be individually fused with a 10 Amp fuse. I never said, "Use a 40 Amp fuse". I said, there can be 4 TIMES the current during a Short Circuit situation. Can't you read? And if the charge controller were to fail then Andy's battery bank can discharge a whopping 100 AMPS into the Solar Panels = A FIRE !!! You know absolutely nothing about designing Solar Panel system ...

[@teror1sta]

@@MrSummitville " Pls do not answer me " I don't need to read nonsense

[@MrSummitville]

@@teror1sta You posted nonsense. I replied with the proper answer. Now, you cannot deal with the truth ...

[@penandpike]

Fuses are much quicker in some unfortunate event and without surge protection I would have kept them.

[@electrodacus]

25A is not enough for two parallel set of panels even if your panels are older. Especially as your ambient will be high and even more so in that cabinet.

[@marv011]

25A should be far enough!? Usually Breakers should trigger at 3times the named current? Or are there different behaviors of AC or DC breakers?

[@jmaus2k]

@@marv011 No, you want fuses for solar DC rated at 1.55x the rated panel current. Solar can produce more than their rating at time. And fuses are always sized for 125% of the continuous current. They can take higher than rated current for 1 minute....but solar is all day.

[@jmaus2k]

I think these were 9A panels so a set of two at 18A x 1.55 = 28A. Yeah, not enough by the book. But pretty close and likely won't be a problem since his panels are 10% lower than rated based on age. He had 10A fuses on each string before which I think would have blown on the hottest days.

[@electrodacus]

@@jmaus2k Doubt those panels have more than 5% degradation. Breakers depending on ambient can trip way below 25A rated current. A 32A breaker will be needed for two parallel panels made with 6" cells. You will designed breakers or fuse rating so that max continuous current is about 66% of breaker rating.

[@OffGridGarageAustralia]

The panels can still produce a bit over 10A in a short under ideal conditions. Under normal conditions, I get 7A-8A out of each string. I have two strings in parallel. If I get more, I have to replace the breaker with a larger one.