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Why Balcony Solar Panels Haven’t Taken Off in the US
(www.wired.com)
This is a most excellent place for technology news and articles.
The inverter in these is designed to shut down if it doesn't detect a waveform from the grid to sync with - they are unable to create a 50 Hz AC wave on their own. As long as the hardware is legit (which is a big if with how easy it is to get unsafe junk in from China) there is no safety issue, it's purely regulatory.