Depending on brand, u may need one adapter for ur xbox (ethernet-to-power conversion) and another one at ur switch/hub/router (power-to-ethernet)
Usually it works well, but beware that sometimes some equipments have problems to cross circuit-breakers. Other problem is high-noisy equipments on same circuits, such as blender or vacuum-cleaners
About security: Does it have any security? such as a "wep" as wireless networks? Without this, u better take care of ur passwords