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Re:Plug-In Solar Panels Starting to Sprout in U.S. Backyards by 0xbadcafebee on Sunday August 09, 2026 @03:17PM (#49234690)
The device looks for an existing signal from the grid, and if it doesn't find it, it stops feeding power. It even waits for 3-5 minutes before trying again plus some random jitter to avoid thundering herd. It's been a standard in Europe for a while and now finally in the US. This of course depends on the utility and state as not all of them have adopted it but it's quickly becoming the standard everywhere.

IEEE 1547 (interconnection behavior), UL 1741 (inverter product safety), UL 3700 (plug-in solar). (also there are newer revisions you need of some standards like UL 1741)

Re:Plug-In Solar Panels Starting to Sprout in U.S. Backyards by lokar on Sunday August 09, 2026 @03:42PM (#49235001)
Also, utility line workers always treat everything as live until they isolate it and confirm it’s not live (or do the work live in some cases).
Re:Plug-In Solar Panels Starting to Sprout in U.S. Backyards by amluto on Sunday August 09, 2026 @04:33PM (#49235543)
I once chatted with some line workers working nearby, and I asked them what they did about residential solar. They said they didn’t particularly care about anti-islanding: if they needed to, they would deliberately short all the customer wires to ground, and if anything hadn’t turned off, then breakers would trip.
Re:Plug-In Solar Panels Starting to Sprout in U.S. Backyards by t0mas88 on Sunday August 09, 2026 @06:08PM (#49236627)
They even do that to large transmission lines. First shutdown/isolate, then connect to ground or short circuit. If anyone then accidentally turns something back on it will fail immediately.

A few years ago a transmission line in the Netherlands was energized while it shouldn't be, during maintenance work, which resulted in the whole line starting to smoke, sag and spark: https://youtu.be/nyjCrP38ICc

Re:Plug-In Solar Panels Starting to Sprout in U.S. Backyards by ButlerianJihad on Sunday August 09, 2026 @03:52PM (#49235120)
https://en.wikipedia.org/wiki/Balcony_solar_power

  In the United States, Underwriters Laboratories developed the UL 3700 standard specifically for plug-in solar devices, establishing safety specifications for microinverters and connection systems used in these applications.[2] UL-certified plug-in inverters are designed to automatically shut down during grid outages, preventing backfeed that could endanger electrical workers.[7]
So that is the standard failure mode, but do customers understand how it works?

If I had a balcony solar panel, I'd definitely expect it to be providing backup power when we need it the most. I'd expect it to charge a storage battery, not backfeed into the grid.

Surface area means a lot for solar panels. An EV with a solar panel on top is laughable. I own a solar backpack that couldn't charge its power bank within 3 weeks of daily full sun. A "balcony solar panel" may not keep your smartphone charged.

Re:Plug-In Solar Panels Starting to Sprout in U.S. Backyards by beering on Sunday August 09, 2026 @04:22PM (#49235412)
Consumers in Germany generally understand that this is a cost-savings device, not a backup supply of electricity. You tell your neighbors and friends to get it because of the energy bill savings.

They are not as weak as the toy panels you are describing, but they are regulated to 800W max anyways.

Re:Plug-In Solar Panels Starting to Sprout in U.S. Backyards by 0xbadcafebee on Sunday August 09, 2026 @07:37PM (#49237422)
The stated purpose for balcony solar is to reduce your power bill. Nowhere does it state it's for backup power. And whether it helps at all depends entirely on your own situation. If it turns out that you can generate, say, 420w for 8 hours, that's 3.3kW, which is a decent amount of power, probably 1/4 to 1/8 the total draw of many homes. That means 1/4 to 1/8 off your energy bill once it pays for the solar panel.

If you want to convert a solar panel into backup energy, there are many ways to do that, but no solar panel+microinverter are safe to just plug into your home. Whether it's a transfer switch, a "solar generator", or a grid-forming microinverter system, they all require you to be physically disconnected from the grid to continue generating power, or to have things plugged into an explicit "backup load" circuit which doesn't come from the grid.