Hi @Derby003,
I'm assuming you are talking about powerline adaptors, i.e. one plugs into the mains right next to your router and connects to the router via ethernet, and the other one is elsewhere in your house, and broadcasts a Wi-Fi signal ?.
If so, it is hard to say with certainty, I've experienced examples of it working fine, but also examples of not being able to get them to talk. Some people have suggested that the type of RCD's that protect the different circuits can have an impact on whether it works well, but I'm really not sure if that is true or not. As long as both circuits go to the same distribution board then in theory it should work, but as I say, I've seen examples where it just didn't want to work, and I think some people have got it working, but not at the full speed they expected.
Different powerline adaptors may specify different ranges for the max length of mains cable between units, but 300 metres is fairly common for normal 'home' devices.
