You can trust a stud finder for the most part, but you shouldn’t do so blindly. As basic stud finders detect changes in frequency—and the most typical kinds are really only rated to do so through drywall—anything behind the wall can trigger one. More advanced stud finders can detect different substances and even live wires. Still, this doesn’t mean a stud finder will be 100% accurate. Few things are! Whenever dealing with electricity, ensure that all power in the area is out before proceeding.