I cannot speak for all models of APs, but I have several installations with a UAP-AC-PRO with just a power injector to power it.? You can use either the LAN input to the power injector or the secondary port on the AP? to supply the LAN to your Ethernet switch.? Might be easier to set it up first with it connected to the main lan and then move it to your remote location.? But I believe the last one I set up, I was able to do it without even connecting to the main lan first.? But it is? important to enable wireless uplinks in the site settings and in the surrounding access points.? Of course it has to be close enough to other access points to make a wireless link.