WR-03Check for pipes and cables, and know your isolation pointsCables and pipes can run almost anywhere in a wall, not just in the 'safe zones' near sockets and switches. Use a detector, but treat its result as a guide, not proof — it can miss deep cables, cables in metal conduit, anything behind metal-backed plasterboard, and metal studs confuse cheap detectors further. Before you drill, find your stopcock (usually under the kitchen sink) and check it turns freely, so you can shut the water off fast if you hit a pipe. If you have any doubt about what's behind the wall, isolate the relevant circuit at the consumer unit before drilling.