GW-04Confirm timber or metal stud, and check for cables and pipesIf you need to fix into a stud, drill a small 2-3mm pilot hole and pull the drill bit out to check the dust. Pale dust with fine wood curls means timber; fine, grey, glittery swarf means metal stud. Cables and pipes can run almost anywhere, not just in the usual safe zones, and a detector can miss cables that are deep, in conduit, or behind metal-backed board — treat every wall as live until you prove otherwise. Find your stopcock now, usually under the kitchen sink, and check it turns, so you can shut the water off instantly if you hit a pipe; if you have any doubt about what is behind the wall, isolate the relevant circuit at the consumer unit before you drill.