No problem, as long as it is the same power grid. After all, the connection runs via the power cable.
We have networked our house with it, which is much safer, faster, easier and has less radiation than working with WLAN repeaters. But this repater function also works great when switched on.
However, the speed decreases with distance from the router. On the same floor as the router: full maximum speed. 3 floors away: only 20%.