To blame the DC isolator for a fire begs the question as to exactly why it has failed - unapproved switch design or incorrect selection / installation. This recommendation to delete an isolator seems strange to me. Perhaps solar panels should not be installed in a sunny location? Then everything will be within ratings 😂

So how exactly does a separate DC isolator cause a fire?

Horrendous to hear about the tragic loss of life, especially someone so young. Nobody should be exposed to danger when going to work that can result in injury and worse death. Thoughts with the family. Got to say I agree with the comments here. DC isolators in true form separate to electrical equipment aka an inverter are essential. It allows safe working practices. Its time industry faced up to the real problem of poor installation. From the hooks to the isolators. I have written to the authors of that document discussed to find out who exactly was involved in its production and if they would like to help remove those poor installation practices rather than essential system components. Thanks for sharing!

I _think_ the report means that: *1)* *_poor quality_* DC isolators; *2)* cables with *no* bootlace ferrules. Should *not* be fitted.

A fire caused by a faulty solar charge controller is nothing to do with a DC isolation switch, if a separate isolation switch is installed.

Victron doesn't make crap, they have no chance of blaming victronenergy.

I use a polarised 500v breaker and double insulate the solar cable connetion point, cut the ferrule to size, but to cut power my inverter has an intigrated isolator switch. At max current & volts the temperature of the breaker connection points is not more than 2 degrees above ambient. Personaly I think testing thermals during max loading is a must.

DC isolator installation depends on country regulation. In my country if the DC cable goes inside the attic then within 5 meter from the entry point a DC isolator must be installed and operated remotely. The idea is that is should be controlled by the main/firefighter switch to isolate the panels from DC cables that are running inside the house to avoid electronic shock. There is only few high quality 1000V DC rated products are available. There is always a cheap alternative from a well known online reseller, but I would not install those to my house.

I don’t understand. Neither of the failures highlighted related to DC isolators. How do the ones fitted inside inverters differ from those selected for use outside inverters. Simply stating “there is a problem with them so don’t fit them” doesn’t seem to make any sense to me. Surely a review of the selection and choice of the isolators would be more appropriate.

Do not disconnect under load for 500V DC ? There must be 1000's of solar PV installations just in the UK. I bet 99% of them have a DC isolator since the regs does mention it - ours does.

if the dc isolator on the inverter is ok as an isolator I see no problem useing that only. however if the inverter is monted inside the building I would want a Dc isolator installed outside the house incase there is a Fire for whatever reason so the fire brigade don´t have to go inside the bulding to look for the isolator switch.

A tragic story about Matthew Camble. The strong reminder that if we feel that it’s not safe doing something, then it probably isn’t. As an electrician who has deviated away from the mainstream for sometime, I look forward to watching your videos to keep me abreast of the industry changes. Thank you 👍

So, who is going to trust technology over a switch? In the same way, a 3phase Spd that takes the supply straight down to earth without any over current protection. Those of us that have been around long enough will know, if something can go wrong it will. So, when it goes wrong, will your insurance pay out? To me at least, when it comes to electrical safety, give me a good old fashioned isolator any day. When it's off, it's off end of story.

Where's the explanation about how a DC isolator could cause a fire?

Talk about a "U turn" on DC isolators, first they insist you fit them, despite the Inverter manufacturers stating they are unnecessary - you just couldn't make it up.

I would be interested to know the mode of failure of the dc isolators on PV installations. Having worked in industry with extensive dc systems- 55V, 110V, 240V, and 485V, I have never experienced any of the dc switchgear to fail. Indeed, I regard isolators as essential, so is this just a knee-jerk response to incidents or has proper investigation identified the fault? Why would an isolator within the control panel be any safer than an external one? By the way, an endorsement from Greta Thunberg would not tempt me to buy anything, even with triple Nectar points!

Many countries (e.g. Germany) actually mandate DC isolation switches for solar installation for fire reasons.

If your pulling DC strings out of an inverter under load, you are dancing with the DC Arc Angels! Its not going to be nice for you in the right conditions. I'm an advocate for THE CORRECT TYPE of isolators.

Sounds more like a "DON'T INSTALL CRAPPY CHINESE OFFBRAND DC ISOLATORS WHICH COST 1/50th OF A SAME RATING PRODUCT FROM A KNOWN BRAND"

Great content but I think you buried the lead on your first article on "DC Isolators"....................! Literally on the next paragraph down is the statement; "The Code applies to all stages of a project....... **The recommendations in this guide are NOT INTENDED for single residence dwellings (detached or connected), or to roof-integrated PV Panel systems" That's a very definitive distinction.

It's fascinating to see how regulations and recommendations around the world lurch around like this. Personally I reckon you always want an external way to remove supply from a device. Everything has a built in on/off switch yet we still have means to isolate wiring in standard AC wiring. That shouldn't change with PV. If anything given the sort of voltages that are permitted it should be mandatory. Not sure on the max voltage over there but many places are now moving to allow 1kV or higher even in domestic. Use a non-rubbish properly spec'd DC isolator and don't put it in a situation where it is going to be weather damaged.

Solar strings are class 5 cables and should have an ultrasonic weld or a bootlace ferrule as a minimum. I've never seen any signs of heat damage with the above but too many without. Also, adhereeing to MI for torque settings and use a descent tool will certainly help to reduce lose terminations and heat.

This was the law until recently in Australia. (ROOFTOP isolators) It caused HEAPS of fires! Finally the requirement of rooftop isolators has been dropped.

You can but they need to be the tandem type breaks with a mosfet switch and isolates with a electromagnetic contactor. These are also built into several types of charge regulators as well.❤

Can someone explain how a DC isolator might cause a fire? Or how a fault that caused a fire might not have done so had there been no DC isolator installed? As Joe said there's a hefty line up of expertise behind this advice, so it should be taken seriously. But even so what is the _exact_ problem?

I would suggest that perhaps many isolators are not capable of clearly breaking the on line voltage at the rated current. A line of panels can easily get up to 600v (shouldn't but they do), if installers are not allowing for this and not wiring the internal switches in series then all hell is going to occur. With DC the trick is to make the gap on the contacts as big as possible, and that means series contacts, and each contact must be capable of carrying full current. I would suggest a factor of at least 1.3 safety. Panel array = 20Amps at 450v(theoretical max), then an Isolator made to break full load current at full voltage of around 25 or 30 Amps at 585-600v DC. Often that means wiring 2 sets of contacts in series in both legs. Many 'isolators' are not meant for ON-load breaking but often only capable of OFF-load disconnection, it you shut the inverter down, then isolate the panels (with lock) to work on them. I also suggest that the Isolator is placed in a floor accessible position. Roof is no good.

In Australia, the DC isolators usually corrode, and catch on fire, besides they offer no overload/fault protection and are pretty much useless. Problem is that the Australian code says that they must be fitted, but they at least should not be up on the roof, where the weather causes them to fail, and instead be sited in a proper weatherproof cabinet.

I use a snubber circuit (a resistor and condenser in series) across the contacts on the switch which stops the small dc arc across the switch when opening and closing the contacts. (it's old school man)

Question. i rent a unit with a garage down stairs with only light circuit. probably has no earth (at least not at switch when i checked ). I want a power point supply to mess with hobby electronics only in shed. Can i take power off the light or is there a chargeable device that i can plug into mains in the unit and carry it downstairs to shed as a temporary power supply ? Thats assuming there is no earth at the light fitting when i get around to checking it.

I think main reasons are 1) poor quality components 2) poor quality work

As a firefighter and an electrician, picture this: We're responding to a fire involving a solar panel fire and they removed the isolators on the solar panels so we're gunna yank mc4s until they're all isolated? yea I'm sticking to a remote disconnection device that isolates panel to panel connections my house is powered by a hybrid solar system (it can act as a grid tied system and an off grid system) for 5 years now and nothing happened no fires nothing. I even built the batteries myself sometimes it's when people get curious and touch what shouldn't be touched like the solar installation I did to a residential structure I told them not to tamper the settings and even let them sign a waiver that if there are signs of tampering, I have the right to waive my involvement in an incident involved, lo and behold they got curious they touched the settings and permanently damaged the lead acid batteries by charging it with the wrong voltage and current causing it to bloat and explode

I am not sure I agree with RISCA, do they know something the IET do not? If there is no DC isolator then how do you isolate when you need to run tests on the panels and most importantly. In a few years time when you need to replace the inverter do they think it will be done at night so there is no DC voltage/Current? (I am assuming Domestic here) Very important point to consider is that not all Solar PV panels have an optimiser which detect no inverter and drop the output to 1volt. If they think the MC4s or the DC isolators are the cause they need to investigate if they are upto the job. are the MC4s on the panel compatiable with the installers MC4s connectors and crimp tool? Not all brands play together nicely. If they are upto the job was the install done properly by a competent person. Local isolation is in BS7671 for a reason and that reason is to save lives.

Advice please. I need 15kwh a day to power for power outages that can last from a couple hours to a few days. I'm in Michigan so my solar hours is 4.48, 1,278 Kwh per 1Kw, says need 4.24 Kwh array I'm looking at a 400w, 36v panel, says output DC 39V, 10.25a max, transfer efficiency greater or equal to 21% A MPPT Charge controller of 100a, says 12/24/36/48v Auto, Max Input 100v. Max charging current 100a. Max Input volts of panels should be 30v-45v (for 24v battery). Max Input power of panels should be 2000w. Output voltage DC5v/1.5a Inverter of 4000w/8000w Peak, Pure Sine Wave Power Inverter, DC24v-AC110 And Battery is LiTime 24v 100Ah, LifeP04 Lithium Ion, Build-in 100a BMS, 2,560 Wh Energy. Up to 4P2S (don't know what that means) 48v battery 400Ah of 20.48 Kwh It's only 1000sq' apartment, 2bd/2ba. Old Kenmore Fridge, elec range, micro, dishwasher (which I'd forgo during an outage), a couple computers and tvs, wifi, lights, a mini-fridge, that's about it. No washer/dryer and if I did use my hair dryer, it's 5 mins or less, but I don't use it every day (and my housemate is bald). For obvs. reasons I wanna keep the heat on and the fridge. We'd unplug things we don't need for a few days, but I'll stick with what we've averaged over the last year anyway just to be safe at the 15Kwh a day. Am I on the right track here? Too much, too little, just right? Any part of this not work with another or could be downgraded or done better/easier/cheaper? Any part of it I don't need? Anything I do that's not here? What I have here is about $1,450. Thanks for your time!

In many countries a DC isolator is required by law, and it is required to be mounted on a non flammable surface. Personally I think all electronics related solar panels including batteries should be mounted in a fire proof room, and ideally in a separate part of the house or in a separate building that are non flammable.

The selected words of the week are fungus and gingerbread . And as always thank you very much. It's really fun to see the electricity news, I appreciate it very much.

A legal requirement in Australia, roof mounted double pole isolator for Firemen to access during a fire.

So why can an isolator, a safety device....cause fires ?

I use specially designed Kraus and Naimer 1000 volt DC isolators. There are 2 lots of 3 poles in series in these isolators. Rule 1 never open the switch when it has a load on it. Started in the trade in 1974 and I might just know a bit more than some insurance Johnny.

The beard looks good on you , Joe. Thanks for the news. Happy New Year.

Instead of an isolator, could a switch to ground be as effective? ( Or between + and - of the solar leads) This way the contacts are not in use until that time of need. Could be installed as a single use emergency device to ensure solar voltage is zero.

With out a DC isolator you would have to make the PV connection in the night I can’t see how a dc isolator of the correct specifications can cause a fire

Thank you for this valuable information. When I was installing my panels last year, I already didn't put any DC isolator on the roof. All MC4 connectors are secured and ON the roof tiles, which are made of concrete. Electrical engineers are well aware, that the main problem in electrical circuits are contacts and switches. High voltage DC is the worst, if arcing starts, it will burn until the contacts are separated at least an inch or so. I have MC4 HV fuses on positive and negative side and a HV DC fuses before the inverter. Solar cables are laid separated about 2 inches, in case of rodents would eat thru insulation. I think this will do. Better safe then sorry.

Handy info. I would be interested to know how old the PV systems were that caught fire. My oldest system has been in for 13 years now and it's not caught fire yet. Maybe I should start checking the DC isolators with a thermal camera as a precaution?

Very interesting. .can't see how a dc isolator would have caused the problem. .do the pv installers fit smoke alarms in the attic space .

I see no reason to banish DC isolators seeing as the inbuilt DC isolators are exactly the same mechanism, seems ridiculous to me. Also how are you supposed to safely test short circuit currents without an additional DC isolator. (If you don’t have the pv specific test equipment)

Most inverter isolators are non lockable. DC isolators are double pole with air gap but some have screw terminals could this be the weak link. Maybe the connection should be mc4 as we see on Chinese made isolators

My solar PV system was installed in 2015, and has DC & AC isolators. So far the only failure has been the AC isolator (a couple of years after installation).

How would we go about testing on an EICR if we can't isolate the DC comming in?

What is the standard Cable size for solar power supply (from the panels to the solar charger?

MCS install fail if you don't fit an isolator separate from the inverter so ill wait until there is an update telling me otherwise. Insurance company 'experts' Isolators don't cause fires unless you use an AC instead of a DC and vice versa.

go for the full ZZ-Top!

Livoltek battery in that solar training firms leaflet... cough reviewed that good system

I'm not a qualified Sparkie and perhaps I'm thinking about _old_ old PV panels here, but can modern panels produce enough current to cause fires if improperly isolated/not connected to a suitable load? If that's the case then long gone are the days when leaving a PV panel disconnected was safe - Sounds like we _Ha'a Goers_ need to start treating these with the same degree of care and caution as for a Li-Ion battery pack! ☀🔋🔥😳 Though if modern PV panels are *that* powerful, perhaps the concept of installing a couple on the walls of my North-facing flat is no longer as ridiculous an idea as it once might've sounded. If they can produce 200wH even in that sort of siting, that's still a saving¹ of 80p/day on my electricity bill... 💰😀 (¹ - That's of course before we start getting onto the cost of 2-4 PV panels, the inverter, and the fact that - Due to escape route considerations - My installation has no safe place to site a battery rack! 😉)

Happy new year guys.

I do not understand why UK electricians don’t explore micro inverters more. Easy to commission and much safer due to isolation and dealing with smaller DC voltage.

Just had a really fun time trying to pry off some old brittle mc4's under an old SMA inverter. Voc=800V - really would have appreciated a DC isolator!!!

My best bet would be some of THESE words: fungus, Joe, square, circle, gingerbread, Mail, air fryer. Teacher A Trade, flame, Icon, cigar, few frights, Swiss Army knife, Boy Scouts, Ultra, kit for explosive areas, Grizzly Adams, and torque calibrated arm Thank you :-)

There should be some regulations to minimize the fire risks: as few components between charge controller and solar panels as possible, minimize wiring between each component and all component rated with safety in mind (700V array => rated for 700V + 20% => 900V). Why you need to connect all solar panels in series? 30V per panel and 120V to 240V should be enough to build an array to get the cables down. Look what a cable isolation fault on a 700V system looks like and you never put the + and - cables in the same pipe.

But that recommendation clearly says: " . . . not intended for single residence dwellings . . . ". So HMO's and up?

Perhaps, with all the news of house fires allegedly being caused by photo voltaic systems, the creators of a training program might think of a different name than "Green Spark"

Air fryer and gingerbread house, seem like additional oddities to me 😊

Groovy, thanks.

This morning I tested a mc4 connector to see if it would burn result they support fire and do not self extinguish There for a damage mc4 plug in /out under load is a fire 🔥 risk

So, those news media reports are ... ridiculously lacking in any detail or knowledge. A fire investigator can absolutely tell the difference between a fire caused by a solar panel, an isolator on the roof (a huge huge mistake), or a charge controller fire (typically situated inside or in a sealed enclosure). DC isolators exposed to the elements should be avoided ALWAYS. Now I know there was a time when I think parts of Australia tried to require them up on the roof for fire fighters, but manual isolators just shouldn't be up on the roof or ever exposed to the weather, even if they have IP65 or IP67 sealing. IMHO, I would avoid as much junk up on the roof as possible. The combiner box, for example, should not be up on the roof either. Backhaul the individual strings down to an easily accessible place for the combiner box. Why? * Manual DC isolators are usually NOT spring loaded and cannot quickly break ARCs. This causes carbon build-up on the contacts. Particularly at the voltages solar panels operate at. * Manual DC isolators CANNOT be switched under load, but most people do it anyway. This causes carbon build-up on the contacts. * Manual DC isolators DO NOT HAVE A THERMAL TRIP, meaning that they will not automatically trip on the most common failure case for manual DC isolators. * The contacts are extremely vulnerable to corrosion and oxidation due to exposure to the weather. This causes additional resistance. The carbon build-up and resistance ultimately creates a thermal event. The plastic casing will melt and depending on how it is mounted eventually catch something on fire. Having this up on the roof where it is difficult to inspect regularly makes it doubly dangerous. And that is why manual DC isolators should never be installed anywhere where they are exposed to the elements, or anywhere "just because it might seem like a good idea", by installers or anyone else. Use proper UNPOLARIZED double-pole DC breakers for your disconnects. The only DC isolator you ever see should be the one integrated into the solar inverter (if there is one). And even that might not be the best idea in the world. Proper unpolarized double-pole DC breakers rated for the solar voltages involved should be used pretty much wherever you want a disconnect. They should be in properly sealed boxes or inside and NEVER exposed to the elements. - Why unpolarized? Most people, even electricians, tend to wire polarized DC breakers incorrectly and in solar applications it is often impossible to wire them correctly because the power might flow both ways, and the short condition might also come from either side and thus also flow both ways. Unpolarized DC breakers typically do not have the two magnets on either side of the arc gap to direct the arc (polarized DC breakers typically have such magnets). - Why 2-pole. To properly isolate the subsystems you want to isolate both the positive and the negative. - Why DC breakers instead of manual disconnects? DC breakers have thermal trips, spring loaded disconnection, and ARC extinguishers internally. The typical failure case for a properly installed DC breaker is to trip rather than catch fire. - Automatically trips on over-current and instantly trips on a short, and can be tested as such. - But be warned that IMPROPER installation of a DC breaker (improper voltage range for voltages involved, improper use of a polarized DC breaker instead of using an unpolarized breaker) can also lead to a fire. -- Also, the wiring for a solar string MUST ALWAYS BE FUSED, in addition to any breakers. This is typically done inside the combiner box (and you should have a combiner box even if you aren't paralleling any strings). The fuse MUST be a 10x38mm 1000V DC ceramic fuse for solar applications, period, and the amperage should be as specified by the panel label. Each string must be separately fused (the combiner box typically has a fuse position for each string being combined, including if only one string). Some people argue about breakers and fuses on the same string, and think the breaker's function is somehow rendered useless by the fuse. It is not. That breakers and fuses serve two different functions. The fuse is the primary protection against a short. The breaker is primarily there as an ARC-safe disconnect, and also serves as a backup safety device against a panel short. Plus having a breaker at the combiner box AND ALSO just prior to the charge controller provides protection for wiring faults that backfeed through the charge controller from the battery. "Popping the fuse" IS NOT AN ARC-SAFE disconnect. Its a last resort if it didn't blow on its own and the breaker didn't trip either, but you don't pop a solar fuse as your "disconnect". You can only pull the fuse safely after turning off the breaker. -Matt

yet, I had my bypassed and the electrician found the installers did a dodgy job as he worked on the bypass. I only have the isolators next to the inverter now, even though they did a dodgy job there too.

How are you supposed to change a faulty inverter if you can’t isolate the dc & ac supplies ?

This is a serious allegation about Victron energy's MPPT. Do you have a source for that?

Gingerbread & Campari..? Good content, thanks.

How is an isolator causing fires,some inverter manufacturers recommended or require separate DC isolators, despite their equipment having a built in isolator, so what happens then. As usual, things like this happen and there's no proper guidance we have several bodies giving conflicting information and the only losers are the installers and customers.

When is an isolator a switch disconnector ?

Thanks for another great news broadcast 👍

no mention of why Isolators are bad? why?

If the Victron system had no DC isolator switch, why mention it here? Are there no example cases where the DC isolator switch actually caused the issue?

Air fryer and Gingerbread. Great listen.

no way i would trust an integrated switch , all you have to do is keep the isolators out of the darn sun

What I dont get with house electrical installs thay how in the high holy hell do you guys not fuse the solar in line??? Only the outgoing line from the inverter. Its standard in marine electrical since 2018 to fuse the solar to mppt line. Hell ive started including after panel inline fuses for the individual panels.

I am sorry for the friends and family of the man killed but how on earth is it the responsibility of a company that a tree happens to fall onto one of their workers? If we are saying that the man killed should not have been working outdoors in a storm then we are heading for very extended power outages during poor weather that will make today's mains failures look like a very minor inconvenience - waiting for 'acceptable' or 'safe' weather to fix things. Who decides what is 'acceptable' or 'safe'? *Surely* it has got to be the person (or his immediate supervisor) 'on the ground'? This is such a random event that could happen to *anyone* even someone happily sitting at home. We need to have a sensible system in place to prevent over-bearing and impractical safety regulation whilst at the same time providing compensation for those unlucky enough to be involved in this sort of tragedy (especially public service workers) without labelling companies (let alone individuals) as 'criminals'!

They should have installed In-line fuses for the solar panels then the DC panels wouldn't be a problem.

Tis the law where I am; plus there is new standards for PV isolators

Sorry may be just I'm just a bit thick Please explain How does an isolator cause a fire

I’m gonna guess fungus and gingerbread as the two words you had to sneak in.

Don't want a fire? ENPHASE.

Shame you don't explain why solar isolators are considered dangerous. Why is this?

I’m glad I don’t have solar and never will

Victron make top shelf products it wasn't the charge controller

The clock is ticking, only it isn’t. 5:06

So I edit my previously top rated comment to add a link to the document mentioned and my comment is then deleted. By who?

The words were fungus and grizzly for sure.

Gingerbread and Airfryer..... Technically Four words.

Think ill just keep the money in the bank earning interest and use that to offset the increased electricity bill and carry on getting electricity via the grid....

Gingerbread and air fryer 🤘🤘🤘

fungus and gingerbread i believe are the slip in words

So eliminate DC isolators in a bid to make PV installation more foolproof. I mean im all for it. One less thing to mount and terminate 😅

Gingerbread Air fryer?

Insurance companies are not electrical companies.

Airfryer streamlined

Gingerbread and air fryer

Air fryer and gingerbread!

Greta equates to an air fryer.

gingerbread airfryer :)