If your house has no electricity and you're living in it without electricity and it's not just because of a power outage then yes the house could be condemned and marked not safe for occupancy in some places.
It's more of a city code thing though and not an actual legal thing.
It's not illegal to live in a home without electricity or even running water but some cities have it in their health and safety code that a house must have running water, electricity, natural gas and city sewer etc to be habitable in that particular city or town.
If you have kids then the kids could be taken away from you if you have no electricity, running water, proper heat etc.
However if nobody is living in the home without electricity then it will not be condemned because of that alone.
You do have to leave your home or house if it's been condemned.
If your home has been condemned you'll be given notice that you'll need to vacate the premises and retrieve any of your belongings.
When a home or building is condemned it means that it was found to be unsafe for human habitation.
You can however return to the home to tear it down or work on it to bring it back up to code but you cannot live in the home until it's fixed.
Some homes are beyond repair and the only thing that you can do is to tear the home down and build a new one or find another place to live.
If you own the property you can still go onto the property as much as you want but you cannot occupy the building or home to live there.
Homes can be condemned for no running water, no electricity, no heating, bad roof, poor structure, crumbling foundation etc.
In some cases a city can force the tear down of a condemned building or home once they go through a court process.
If you do try to live in the condemned home then you could be arrested so it's best to find other living arrangements.