It is good that people are aware of the risk, but in reality the risk is quite low. It is standard procedure for a lineman to ground a line he's about to work on, to mitigate the risk of any power source feeding it. But I'd never advocate a DIY setup. But damn near everyone I know with a portable generator has a suicide cord and just flips the mains. Ah well.
How many linemen are killed a year in the US due to backup generators or similar? Are there no procedures they can do to work on lines safer?
But since lives are at stake here, we prefer to have layers of protection rather than just one thing. Grounding jumpers can fail if not properly connected (a large mechanical force will be applied to the jumper when the phase-to-ground fault current flows through it).
Bottom line, respect the electrical code and connect generators through a transfer switch. These rules are in place for a reason.
In fact it's likely the transformer on the street between your house and the network that's responsible for the death of the linemen. IIRC that's a step down transformer (so step up when run backwards like this.)
oh, you mean like solar PV on-grid setups ...
Some battery systems, like the Tesla Powerwall include a contactor that allow their microgrid battery systems to conform to the standard without a loss of power to the site they power.
Needless to say, if you're looking for a backup power source this isn't a property you want.
(an idiot who the state of NM certified last year to install his own on-grid solar PV system, so doubly an idiot!)
A correct install is of course also required as it's possible to screw up and unintentionally cripple this important safety feature.
I wonder if the wiring is basically plug the 240v split phase into a special outlet in the house that feeds the transfer switch. The 80amp charger is then just a charger.
Could be completely wrong though. We'll know more at launch.
What I would like to figure out is if it can actually backfeed the home with 240V split phase power. That would be a seriously big deal if it could, it's not a common generator feature as it is. I'm skeptical, but they did claim it could transition from charging to supplying the house and back to charging when the power returned. Probably some fine print there where they say "only with the 120V charger". Otherwise, that would just be killer. An automatic whole-house UPS that can easily support all your needs for hours or even a couple days in a pinch.