Do not cut into a wall when you cannot identify the cavity conditions, utilities, fire blocks or permission to alter it. Masonry, tile, lath and plaster, fireplace assemblies and shared walls may require a different method and professional assessment.
Stop if a plug, receptacle or cord is loose, discolored, damaged, buzzing or warm. A cable cover is not a repair. If the original power cord cannot reach the outlet, do not solve that by hiding an ordinary extension cord inside the wall.
Follow the television, mount, furniture, raceway and power-product instructions together. When instructions conflict or electrical work is involved, use a qualified professional and the requirements that apply where the home is located.