Electronics > Projects, Designs, and Technical Stuff
Lots of recalls of solar panel DC disconnect switches
thm_w:
--- Quote from: floobydust on May 31, 2019, 06:37:19 pm ---Solar electrical equipment somehow can ignore mains electrical safety standards.
Approvals are required on components, wire, boxes etc. but this install looks hokey.
--- End quote ---
It does, compare to Daves system, conductors were properly enclosed in tubing just as would be required for mains.
Its hard to tell what sort of voltage would be present though, there are a lot of wires going out but then again a ton of panels too. I think that would be good if it were 48V, but I assume its higher than that.
Someone:
--- Quote from: SparkyFX on May 31, 2019, 11:00:04 pm ---Maybe the switch is required at that place for firefighters to be able to disconnect it and not get additional dangers due to the energy generated by the panels, it would be bad when the safety device itself turns into the source of the hazard.
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You guessed correctly, fire brigade like to have an isolation switch on energy supplies as close to the source as practical. But the safety feature is a common failure and can create a fire in the process. The service fuses on the feeds to the house have proven to be acceptable, but the solar installation standards required these switches instead.
bdunham7:
Are these high voltage string systems still commonly installed in grid-tied residential systems? I did ours a bit over 6 years ago with microinverters (and all-metal electrical enclosures on exposed parts) and they were beginning to become the preferred method at that time here in California. I would have thought they would be the most common method by now.
SparkyFX:
--- Quote from: floobydust on May 31, 2019, 06:37:19 pm ---Solar electrical equipment somehow can ignore mains electrical safety standards.
--- End quote ---
Maybe it could if it was low voltage, but the panels seem to be in series, which might mean if one breaks the energy generated by the others could end up being dissipated there at the fault? Most regulations refer to voltage, not overall power, and they refer to loads, not generators. There is practically a huge loophole in the regulations - maybe its already fixed or about to be fixed.
Some protection features required in mains electrical systems are probably worked around by isolating the system from ground. That might be good that way because it avoids inadvertantly creating a lightning rod (installation on roof) and provides personnel protection from a single failure.
Otherwise you´d need a type B/B+ RCD with DC detection, depending on country.
--- Quote ---Approvals are required on components, wire, boxes etc. but this install looks hokey.
--- End quote ---
I don´t outright see the problem, other than the durability of the plastics -> or the question if it exposed to direct sunlight.
--- Quote from: soldar on May 31, 2019, 11:20:58 pm ---I find it amazing how overbuilt things were in, say, 1950 when Europe had just come out of the war and there was shortages of everything.
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Mostly because materials and mold making were not as they are today. The whole plastics industry developed later, based on the use of oil. Also you could not form such thin walled objects reliably and in such quantities back then, the whole injection molding process is a late development, requiring automation and a thorough R&D. What they had was a huge work force. Well... today things fail because they were driven too far with too little safety margin.
soldar:
--- Quote from: Circlotron on May 31, 2019, 01:52:07 pm --- I think the statement is nationalist, not racist.
Condemning Asian people rather than the Chinese nation would be racist.
--- End quote ---
Not to dwell on this but, if I may digress for just a moment, I believe many younger people are not aware that the word "race" has several meanings and does not only mean biological (white, black, etc) race but also, as the dictionary says:
--- Quote ---a group of people sharing the same culture, history, language, etc.; an ethnic group.
"we Scots were a bloodthirsty race then"
--- End quote ---
In Spanish also the word "raza" has the ethnic and cultural connotation and is often used to denote courage or virtue or good qualities. Like in English and due to American influence the word is drifting away from this meaning.
There are multitude of examples in English.
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