TR-04Check for cables and pipes, and know your isolation pointsCables and pipes can run almost anywhere, not just in the 'safe zones' — a detector helps but misses deep cables, metal conduit, cables behind metal-backed board, and anything hidden by a metal stud frame confusing the reading. Find your stopcock now (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 at all, isolate the relevant circuit at the consumer unit before drilling, and don't drill until you're confident of what's behind the mark.