Electric ceiling heat
you need to know what type of radiant heat cables were used. Some are embedded with fine wires like ThermaRay panels, others are installed between two layers of drywall, mudding the cables in place to maintain a radiant barrier. Repair involves finding the break and reconnection the broken ends with a butt splice. An electrician will be able to find this area with many different tools. I find a tic tracer works well. The issue is that you do not cut into these panels without first marking where the wires are.