I can’t think of a not insane reason anyone would need one.
You can run something like a house off a generator with one if the main breaker is off; in an emergency and the operation reasonably well planned out (don’t overload wall lines you plugged into, etc.) it might be a net benefit. On the reg is asking for death cause there’s safe ways to do it that sane people would plan for on the reg
That would surely only power a single circuit (due to isolation) and if you have to be selective, a critical circuit like your fridge isn’t really likely to have a wall port on the same circuit near where you’d happily have your fume emitting generator…
I’m no electrician but I’ve generally installed automatic transfer switches (ATS) for mine site server cabinets that then power UPS racks and the transfer switch automatically or manually can switch from mains to generator if mains power goes out (which at a mine is all the time). I feel like a similar and safe system must exist for homes. Or something no different to switching solar to grid and back.
But again, not an electrician.
In your typical household panel there is no isolation. If you’re lucky there’s a GFCI for the bathroom and kitchen.
Edit: not to imply GFCI provides isolation either
If you disconnect the mains then the power will be backfed through one of the circuit breakers and back out to others. If the breaker you plugged naughty plug into is off, it’s isolated. Otherwise, it’ll power whatever circuit breakers are on on the breaker panel.
If you don’t disconnect from the mains you’ll kill a person working to fix the electrical lines for your neighborhood.
Yes, safe and automatic things exist to switch automatically - or even hook up a generator in a pinch manually but safely (no naughty plug needed).
Defo don’t backfeed your abode unless you’re gonna die due to some major emergency!
People want them around the holidays because they hang their lights in the wrong direction and end up with 2 female plugs where they needed one to be male… So the want the danger adapter because they are not wanting to take anything down
So someone wires up lights around a bush or tree and one side ending in a socket is powered correctly. But they fucked up and the line to connect to it is flipped; it isn’t a pronged plug but rather another socket.
So instead of rerunning that flipped line of lights, they go cut two extension cords to create The Naughty Plug and use it to run power from the powered socketed plug to the unpowered socketed plug, leaving an energized prong plug vibing somewhere at the end of the line ready to maim, murder, or incinerate someone.
At work, I have a freezer with a couple thousand dollars of product in it. If I lost power and only had male plugs to jerryrig the generator into the circuit, I would. BUT only after turning the mains off and padlocking the panel shut. I didn’t have to do that as I just wired the generator directly to the freezer after disconnecting it from the mains.
Technicaly it is connected through the breaker so you could only supply as much to the rest of the house as that breaker can pass. Not ideal or the proper way of doing it though. Also the reason to disconnect from the grid is that you could start feeding downed power lines, and if line workers go out to work on the lines they can be electrocuted. Also, theres no telling when power will return. There should be a separete input for the generator and a transfer switch to switch between the generator and grid.