In the USA the usual feed is 220.240 VAC. This is 2 phase, 3 wire and homes are generally on one side or the other giving 110 or 120 VAC to the sockets. This is all over the web and I will only summarize here.

Most panels have two rows of breakers, left, right or sides.

Powerline just needs to be on the same side. If not it might not work. But there are bridges an electric technician can install if need be (what it is, is on the web.)

Also, about the Access Point. You may want to consider models like
https://www.amazon.com/dp/B00OIA1Z9I?psc=1&smid=A2F6E975V906X0