CP-02Check for cables and pipes, and know your stopcockCables and pipes can run almost anywhere in a wall, not just in the 'safe zones'. Run a detector over the whole marked line, but still treat every hole as a risk – detectors miss deep cables, cables in metal conduit, and anything behind metal-backed plasterboard. Find your stopcock now (usually under the kitchen sink) and check it turns, so you can shut off water 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 you drill.