BW-03Run a detector and stay cautious before drillingCables and pipes can run anywhere in a wall, and a cheap detector can miss cables that are deep, in metal conduit, behind metal-backed plasterboard, or confused by a metal stud frame. Use your detector on every mark, but still drill carefully and assume something could be there until you've proved otherwise. Before you start, find your stopcock (usually under the kitchen sink) and check it turns, so you can shut off the water instantly if you hit a pipe. If in doubt, isolate the relevant circuit at the consumer unit before drilling, and turn off the water at the stopcock before cutting into anything that could carry water.