EEVblog #1217 - My Home Solar Power System FAILED! - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: May 29, 2019, 11:33:05 pm
content: After 6 years my home solar power installation failed!But *what* component failed? let's find out..

author: maginnovision
author_rank: Super Contributor
timestamp: May 30, 2019, 12:17:37 am
content: If you keep a switch I'd recommend something properly rated. I live in southern california and my junction box(also plastic), which is in the sun 14 hours a day, has never failed in 30 years. There is no discoloration, it isn't brittle, the seal is still good. That or take it out of the loop if you're allowed. If that switch was supposedly rated for that kind of exposure...

author: www2
author_rank: Contributor
timestamp: May 30, 2019, 12:54:13 am
content: I not surprise that this is the reason for the recall.

author: m12lrpv
author_rank: Regular Contributor
timestamp: May 30, 2019, 01:06:56 am
content: funny to think that even a simple bit of electrical tape around the seam would have saved it.

author: Razor512
author_rank: Regular Contributor
timestamp: May 30, 2019, 02:03:51 am
content: For the switch, why not coat the box with a few layers of car paint and clear coat (they typically have UV protection)? Even on old card, I don't see issues with the plastic bumpers having issues with the sunlight.

author: EEVblog
author_rank: Unknown
timestamp: May 30, 2019, 02:29:22 am
content: Quote from: Razor512 on May 30, 2019, 02:03:51 amYep, didn't occur to me at the time, I assumed the box would be rated for long life UV

author: Brumby
author_rank: Unknown
timestamp: May 30, 2019, 02:58:18 am
content: Quote from: EEVblog on May 30, 2019, 02:29:22 amAs would any reasonable person.To me, that choice of switch comes under the heading of "Not fit for purpose".

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 30, 2019, 04:22:48 am
content: Just putting tape over the joint around the box may not do a lot of good. It could even make it worse by trapping water between the tape and the box. I would rather consider running a bead of RTV around the lip (in addition to that black rubber (?) seal. RTV makes a good seal and is "re-enterable" by simply cutting it open with a knife if you need to get back into the box.

author: Dundarave
author_rank: Regular Contributor
timestamp: May 30, 2019, 04:46:32 am
content: There looks like there may be room to mount the new switch under the panel array instead of on its edge?That would both shield it from the sun as well as protect it from direct rainfall.

author: coppercone2
author_rank: Super Contributor
timestamp: May 30, 2019, 04:54:37 am
content: how much is that fault going to take to pay off? how many sunlight hours did that set you back?bad chassis makes me sad

author: eV1Te
author_rank: Regular Contributor
timestamp: May 30, 2019, 07:35:02 am
content: I would replace the isolator switch on the wall as well if it is of the same model. Clearly not made for outdoor use if the plastic degrades after only 6 years.Considering that a switch is mechanical it must be difficult to guarantee good weathersealing around the knob itself. Better to use a box where the knob is under a sealed lid/door I guess.

author: Whales
author_rank: Super Contributor
timestamp: May 30, 2019, 08:38:45 am
content: Dave: I believe the second isolation switch on the roof is a common standard.In the AC distribution industry: it's common for lineworkers not to trust any pole-mounted disconnect (ie levers on the side of poles) or over-head-wire grounding clamps unless they can actually see them. Too many situations where someone has fiddled with them whilst they are working, or thought they were done with the job. I suspect it's the same when solar workers are on the roof: if you can't see the isolator, then it doesn't exist, and/or the customer has forgotten about you and is trying to get their aircon going again.Exact scenarios where a DC disconnector up on the roof would help: not sure, other than perhaps back-feeding to the panels? Otherwise it's just as dangerous up there with or without the isolator, given that the panels are the source? Perhaps moving the feed from the roof to somewhere else in the house is expected, eg when people later change their systems to use big batteries.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 30, 2019, 08:43:58 am
content: I always use diecast aluminium IP68 boxes for anything outdoor. It's the only way to be sure.And what's with "get it replaced" - why aren't you doing it yourself ?

author: capt bullshot
author_rank: Super Contributor
timestamp: May 30, 2019, 08:46:38 am
content: Both isolator switches look pretty pointless to me.The Sunny Boy inverter has an internal DC isolator (the pull tab at the bottom left of it) - here in Germany this is considered safe enough, for sure it passed various certifications, so no extra switch gets installed.And for isolating the AC side, the Sunny Boy also has a total for four N/O single pole internal relays (each two of them in series for Neutral and Live) to safely disconnect the Inverter and Panels from the AC in case of e.g. ground failure (yes, there's also an internal ground fault monitor).So except for breaking local rules, you're totally safe if you bypass the DC isolator switches.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 30, 2019, 08:52:17 am
content: The only reason I can see for a switch up top is that it removes any ground reference, so assuming there aren't any shorts or leakage, you can safely touch any single point in the string, so for example if you discover some panel damage you can investigate without having to go down, or unplug any inter-panel connectors.

author: ogden
author_rank: Super Contributor
timestamp: May 30, 2019, 08:53:22 am
content: Quote from: mikeselectricstuff on May 30, 2019, 08:43:58 amIn such case your equipment is protected not only against UV butmicrometeoritesas well

author: capt bullshot
author_rank: Super Contributor
timestamp: May 30, 2019, 08:55:41 am
content: Quote from: Whales on May 30, 2019, 08:38:45 amIn Europe, there were / are discussions about roof or below the roof mounted DC isolators for solar systems, required by the fire brigade caring about the safety of the firemen. But these weren't poorly encapsulated switches like the one that failed, rather more sophisticated ones that break the DC automatically when the firemen disconnect the house from the AC supply (this is routinely done, and this is why normally a fuse / breaker box is accessible from outside your house).

author: madires
author_rank: Super Contributor
timestamp: May 30, 2019, 10:47:22 am
content: I'd place a piece of aluminium sheet or roof type board a few cm above the switch box for protection against direct sun and rain.

author: Brumby
author_rank: Unknown
timestamp: May 30, 2019, 11:19:54 am
content: Quote from: mikeselectricstuff on May 30, 2019, 08:43:58 amIf Dave isn't a licenced electrician with the training for solar work, it will be illegal for him to touch it. Opening the cover as he did was nudging the line.

author: dcac
author_rank: Frequent Contributor
timestamp: May 30, 2019, 11:57:59 am
content: Quote from: Brumby on May 30, 2019, 11:19:54 amYou’d think on the solar panel side of the installation you could troubleshoot and replace component as long as you know what you are doing. On the grid side though I can understand DIY work isn’t allowed.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 30, 2019, 12:53:33 pm
content: Quote from: Brumby on May 30, 2019, 11:19:54 amWho is ever going to find out ( assuming it's not on video) ?

author: maelli
author_rank: Contributor
timestamp: May 30, 2019, 03:03:13 pm
content: No extra DC disconnecter required in Switzerland, not on the roof, not near the inverter.I do have a Fronius Symo.I am not planning to walk on my roof for the next 25 years, would not be easy in my case.What is required here is a connector box with heavy overvoltage protection MOVs, 1000V, guess this is for lightning protection.This box is also in the basement, where the DC enters the house.

author: HKJ
author_rank: Super Contributor
timestamp: May 30, 2019, 04:58:44 pm
content: Quote from: Brumby on May 30, 2019, 11:19:54 amThese rules are very country specific, with your being based in Australia I suppose you are post is based on the rules that apply to Dave.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 30, 2019, 05:06:51 pm
content: Quote from: HKJ on May 30, 2019, 04:58:44 pmAustralia has some of the stupidest rules on electrical work, which even extend to plug-in appliances, AIUI they arose out of the unions wanting a closed shop and little to do with actual safety.But for a simple like-for-like replacement such as this, who's gonna know if it was even done, let alone who did it?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 30, 2019, 05:39:43 pm
content: @5:22

author: Monkeh
author_rank: Super Contributor
timestamp: May 30, 2019, 05:46:52 pm
content: Quote from: mikeselectricstuff on May 30, 2019, 08:43:58 amI've gathered over the years that Dave is not fond of playing with electricity at voltages capable of harm.

author: free_electron
author_rank: Super Contributor
timestamp: May 30, 2019, 05:48:53 pm
content: who mounts that thing unprotected ? at least mount it UNDER the panels...

author: thm_w
author_rank: Super Contributor
timestamp: May 30, 2019, 09:29:10 pm
content: Quote from: mikeselectricstuff on May 30, 2019, 12:53:33 pmWell thats the point right, say "I'll get someone to do it" then do it yourself.If Dave said publicly at any point that he is performing electrical work it couldtheoreticallybe used against him. ie manufacturer could void the panel or inverter warranty, household insurance can be void if his house burns down and its found to be from solar wiring, etc.

author: jnissen
author_rank: Regular Contributor
timestamp: May 30, 2019, 10:00:40 pm
content: That is one crusty switch and enclosure. Surprised they allow plastic boxes or enclosures at all. I used micro-inverters so there is no DC disconnect switches. The DC to AC disconnect is built into the inverter (likely already built into yours as well). Since I have AC exiting the system then all boxes and switches are in metal code compliant boxes. No issue with UV and water in that case.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 30, 2019, 10:02:36 pm
content: I'm actually stunned by Dave's low expectations. He seems to think it is normal for a "weatherproof" box to fail after a few years, and doesn't seem too hopeful that the rest of his system will survive much longer than a decade.

author: floobydust
author_rank: Super Contributor
timestamp: May 30, 2019, 10:20:43 pm
content: The better outdoor electrical enclosures are fiberglass-reinforced polyester. But direct sun UV and heat will still degrade the material, they don't last forever.Polycarbonate is cheap and terrible in the sun and cracks and yellows. Dave's enclosure failed on a thin web along the gasket cutout, so expansion and contraction there.I think it's a really dangerous failure. Leakage currents to anything nearby due to moisture, rust, electrolysis. At least it didn't arc and carbon track.Are these solar arrays floating going into the inverter? Solar panel ground-fault detection would be useful.

author: Brumby
author_rank: Unknown
timestamp: May 31, 2019, 04:49:11 am
content: Quote from: mikeselectricstuff on May 30, 2019, 05:06:51 pmAs far as I'm aware, the electrician licencing requirement relates to fixed wiring only.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 31, 2019, 08:36:34 am
content: Quote from: Brumby on May 31, 2019, 04:49:11 amI think this varies by state - I saw a vid a while ago by an Aus YTer who said that portable devices were covered in some states. There was also recently a news story about an Aus electronics magazine getting hassle from the licensing authoraties for publishing mains-powered projects.

author: EEVblog
author_rank: Unknown
timestamp: May 31, 2019, 08:55:36 am
content: Quote from: CatalinaWOW on May 30, 2019, 10:02:36 pmI meant at least a decade out of it before trouble. With 12 panels the likelihood that one fails in some way after a decade is certainly non-zero. And throw in Murphy.And it's not "a few years", it's 6 years under the notoriously harsh Australian sun.Even this top quality aussie made one designed for our conditions comes standard with a protective cover:http://www.cobaltsolar.com.au/COBALTBLACK_DCSo, no, not really surprising the UV killed an exposed plastic one, common as mud failure.

author: ogden
author_rank: Super Contributor
timestamp: May 31, 2019, 09:38:36 am
content: Quote from: EEVblog on May 31, 2019, 08:55:36 amHopefully you will do something about it - make sure that switch is installed in metallic all weather enclosure perhaps? Failure mode of those disintegrating plastic boxes collecting water inside (w/o drain!) is real fire hazard. Luckily nothing happenedPerhaps many switch fire incidents reported were caused not by inferior switch but water ingress.

author: EEVblog
author_rank: Unknown
timestamp: May 31, 2019, 10:53:45 am
content: Quote from: ogden on May 31, 2019, 09:38:36 amThey come standard with a basic weather hood.

author: floobydust
author_rank: Super Contributor
timestamp: May 31, 2019, 07:19:10 pm
content: That product has lovely marketing, but where are the product's agency safety approvals? The brochure has a TUV Rheinland logo, but nothing in their certification database. It's probably for the polycarbonate enclosure.I though Australia would be strict about it, the reason for so many DC isolator recalls it seems is anybody can make and sell one. But they have a safety function.They bitch against mains-powered projects in an electronics magazine but not this stuff?DC isolator safety advice

author: Andrew McNamara
author_rank: Regular Contributor
timestamp: June 01, 2019, 03:24:17 am
content: Quote from: floobydust on May 31, 2019, 07:19:10 pmCall me cynical, but most of the rules and regulations in Oz are about protecting vested interested, not the public.

author: coppercone2
author_rank: Super Contributor
timestamp: June 01, 2019, 04:52:31 am
content: that little hat is a stupid fucking idea, its like a bug houselets make life easy for spiders and waspsI hate high surface area not allowed to touch out door shit

author: floobydust
author_rank: Super Contributor
timestamp: June 01, 2019, 06:19:47 am
content: They don't seem to work, apparently the fire department's water nozzle hits at too high a pressure and water gets in the isolator anyway.People hate climbing up there to switch them off to work on their inverters.I saw a petition to get them off the roof, lost the url maybe SEIA sponsored it.

author: madires
author_rank: Super Contributor
timestamp: June 01, 2019, 01:23:29 pm
content: Why not replacing the isolation switch on the roof with a contactor controlled from a location easy to reach? In case of a fire the PV system can be disabled quickly and safely. If the cable to the contactor is damaged everything will be disabled automatically (fail safe). The HV DC from PV panels is a real problem for firefighters. There are reports of buildings with PV panels being let burn down in a controlled manner because of the lack of a cut-off switch for the PV panels on the roof.

author: Yansi
author_rank: Super Contributor
timestamp: June 01, 2019, 01:30:25 pm
content: Quote from: m12lrpv on May 30, 2019, 01:06:56 amIt would not by any means.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 01, 2019, 09:45:21 pm
content: As much as you guys like to bag Australian wiring rules.The rules had it covered. (from ASNZS 5033:2014)QuoteI think the isolator box is probably ABS plastic. These apparently deteriorates more in UV light than poly-carbonate.AFAIK the roof mounted isolator is so fire people can turn it off easily in an emergency. This rule came later and I guess after some incident where the fireys complained.from the same standard:QuotePCE is power conversion equipment.I think a small 3-4mm hole at the bottom is better than an imperfect seal. The seal in that situation can only be imperfect as the conduit is not sealed. Condensation can find it way in through the conduit.Also I think a lot of the early recalled isolators were just AC isolators used for DC. The newer ones are actually approved for breaking DC. Maybe Dave can teardown the damaged DC isolator and see if it has some sort of arc suppression?

author: Yansi
author_rank: Super Contributor
timestamp: June 01, 2019, 09:57:02 pm
content: Yes, I also second the box was cheap standard ABS. I think polycarbonate is one of the more expensive plastics.Well, looking into the disconnect in the Dave's video, I doubt it has any meaningful DC ratings, as it is even wired two contacts in series, which does not instill much confidence in me that it indeed was suited for DC. Such series wired contacts are commonplace where AC contactors/switches are repurposed for DC. But it indeed might be... who knows. I have never had any of these in hand to look at.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: June 02, 2019, 08:05:49 pm
content: Quote from: Andrew McNamara on June 01, 2019, 03:24:17 amCynical!There is anassociated topic, i guess the PV-arrays are galvanically isolated from ground (probably within the inverter), therefore regulations for mains operated equipment might not apply at all. It´s still high voltage DC.Quote from: EEVblog on May 31, 2019, 10:53:45 amLooks more promising, the black color at least indicates more soot (color) in the material, which blocks more UV and is more stable toward it. The hood prevents additional thermal stress on the housing vs. its screws (should they have a different thermal expansion coefficient than the plastics).

author: Yansi
author_rank: Super Contributor
timestamp: June 02, 2019, 08:50:20 pm
content: Quote from: SparkyFX on June 02, 2019, 08:05:49 pm50V is hardly high voltage.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: June 02, 2019, 10:11:17 pm
content: But the panels are in series... read the system voltage on this plate..Not "high voltage" as per definition (>1000VAC rms / >1500VDC), but hazardous, sorry should that have caused confusion.

author: Yansi
author_rank: Super Contributor
timestamp: June 02, 2019, 11:17:41 pm
content: Sorry, I now see I wrote 50V instead of 500V. (Dave measured like 400something volts on the string in the video).But still, up to 1000V is considered low voltage. I may seem picky, but really, its you Germans being picky

author: EEVblog
author_rank: Unknown
timestamp: June 03, 2019, 01:13:10 am
content: Quote from: Yansi on June 01, 2019, 09:57:02 pmFor those interested, the isolator is a bendict LS25 PFLH4http://www.celiss.com/products/files20177311641475463911978.pdf

author: floobydust
author_rank: Super Contributor
timestamp: June 03, 2019, 04:03:57 am
content: Quote from: EEVblog on June 03, 2019, 01:13:10 amIts got agency approvals UL/CSA! And temperature derating curves. It looks really good - IF you can keep it dry.edit: Is "NHP Benedict" some ripoff of the company's name?

author: Poe
author_rank: Frequent Contributor
timestamp: June 03, 2019, 07:39:16 pm
content: Quote from: coppercone2 on May 30, 2019, 04:54:37 amExactly.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: June 04, 2019, 05:40:22 am
content: 500V/7A is not particulary hard for a switch - or two in series.I wonder if they need to be mechanically timed (one advances the other) to improve the arc breaking or if slight dimensional differences alone are sufficient. I mean the spark gap doubles over two switches just because it is double the distance, but do resistance differences between arcs inhibit two arcs in series? As in one switch pulls an arc, therefore there is not enough breakdown voltage left for the other switch, or more current = more plasma/ionized gas = better conductivity = lower voltage drop per distance, like a current dependent resistor, should such a concept exist.This might not be very relevant for a manual operated switch, but for contactors and such.I think such breakers/isolators exist in in actual high voltage applications.Although recently i´ve seen a fail with a standing arc for at least two minutes and grass fire from the molten metal.

author: Krysole
author_rank: Newbie
timestamp: June 04, 2019, 06:45:30 am
content: I stumbled on a strange piece by the ABC 7:30 report on solar systems in here in Australia. No idea why it got recommended to me, but no matter. It looked a little at panel failures, isolator switches and so on, although not in as much depth as they maybe could have. It was only for TV through, but still possibly worth a watch or read.https://youtu.be/10Gnf-wvF7Ahttps://www.abc.net.au/news/2019-05-27/australias-obsession-with-cheap-solar-derailing-market-insiders/11139856Apparently your not the only one having a bit of a problem with weather damage to the switches. Might have to have a quick look at the system on my roof at some point...hmm.

author: wilfred
author_rank: Super Contributor
timestamp: October 27, 2023, 05:15:42 am
content: There was an article on the ABC (Australia) news website about solar system fires today. It was about a DC Isolator on some lady's house.https://www.abc.net.au/news/2023-09-14/solar-panel-fires-increase-dc-isolator-nt-worksafe-warning/102843552We need Bigclive to do a video on why what appears to me to be a simple switch can fail so dramatically so often.I looked at this video to see if Dave said anything relevant but he didn't see flames on his failure.

author: EEVblog
author_rank: Unknown
timestamp: October 28, 2023, 08:41:31 am
content: Quote from: wilfred on October 27, 2023, 05:15:42 amIt would have to be for not adequate arc quenching within the switch mechanism.Might be fine under normal conditions, but get some water ingress and all bets are off.IIRC there are like a dozen or so recalls of various models just in Australia.

author: nctnico
author_rank: Super Contributor
timestamp: October 28, 2023, 10:54:58 am
content: IMHO it is better to get an inverter with an internal DC switch and use (MC4) connectors to attach the wires to the inverter (I have such a model from Growatt). That way you don't need an external switch that is likely to be the cheapest rubbish the installer can buy.

author: floobydust
author_rank: Super Contributor
timestamp: October 28, 2023, 05:59:53 pm
content: Australia removes much-criticized DC isolator mandate Nov. 2021"Water entering DC isolators is identified as the greatest risk and the most common cause of PV system failures.""Rooftop DC isolators and solar inverters were found to be the main causes in solar-related fires. From 2009 to 2015, between 38% and 50% of recorded solar-related fires in WA and NSW were caused by a DC isolator. Prior to 2015, the majority of solar-related fires in Queensland were associated with DC isolators."https://renew.org.au/research/rooftop-dc-isolators-and-solar-system-fires/Uh so without one... you're using a DC isolator located downstream (pun intended) somewhere dry instead?I notice they have no safety certs or approvals, save a few bucks with the chinese specials but the heat+UV is brutal on fiberglass and plastics, they need a better housing arrangement. Maybe aluminum or SS box overtop?

author: EEVblog
author_rank: Unknown
timestamp: October 30, 2023, 12:09:33 am
content: Quote from: floobydust on October 28, 2023, 05:59:53 pmYes, there is a 2nd one next to the inverter.Still outside and subject to weather, but much less harsh than on the roof.https://youtu.be/VGENVguQQmo?t=1252

author: EEVblog
author_rank: Unknown
timestamp: October 30, 2023, 12:37:23 am
content: Quote from: floobydust on October 28, 2023, 05:59:53 pmI didn't know that, interesting.

author: coppice
author_rank: Super Contributor
timestamp: October 30, 2023, 12:43:51 am
content: Quote from: floobydust on October 28, 2023, 05:59:53 pmInteresting that they stopped requiring an isolator, rather than setting standards for something reliable.

author: EEVblog
author_rank: Unknown
timestamp: October 30, 2023, 01:33:13 am
content: Quote from: coppice on October 30, 2023, 12:43:51 amI'd like to see the actual standard. Perhaps they just mean the rooftop one?My inverter also has an isolator tab atthe bottom of it, not sure if that's mandatory? I'd assume so, because NO isolator is at all is kinda nuts.But in my case, three is too many.

author: nctnico
author_rank: Super Contributor
timestamp: October 30, 2023, 04:08:50 pm
content: Having 3 switches is also nuts. It is just adding more points of failure. One of the pictures with the articles linked above showed a wall mounted DC switch (or what is left of it). So be sure to check your wall mounted switch as well.And what does the code actually require? Over here there is much confusion over needing an AC safety switch next to the PV interter. The code actually says a seperator switch is required to disconnect the PV inverter from the grid without a specification where that switch needs to be mounted. A dual pole breaker in the fuse counts as a seperator switch. A safety switch is to switch off machinery with moving / rotating parts which doesn't apply to a PV inverter. Needless to say I didn't install the AC safety switch next to my PV inverter. As an extra AC switch is just another part that can go bad.

author: floobydust
author_rank: Super Contributor
timestamp: October 30, 2023, 05:50:54 pm
content: I vaguely remember the rooftop isolator requirement was for fire crews wanting safety when fire fighting and pouring water on the roof.Of the two energy sources (solar and mains), local disconnects at both. They'll let it burn until the isolator and mains disconnect have been switched off.But I'm not confident with earth-grounded frames and rails and loads of water, that a fire fighter wouldn't get a several hundred V wallop through the water stream/fire hose, including that it can run to the (floating) pumper truck. This is with a series string. I imagine a ground-fault is possible with things burning up.So far solar electrical standards seem a little torn between low cost and dealing with reality.

author: nctnico
author_rank: Super Contributor
timestamp: October 31, 2023, 01:12:01 am
content: Water sprayed from a fire hose doesn't conduct after a few meters.