BB-03Mark the fixing holes and check the wall before you drillHold the box against the wall at the height and angle you want, level it, and mark the screw holes with a pencil. Cables and pipes can run almost anywhere, even outdoors near meter boxes, outside lights or an outside tap, so run a detector over the marks first. Detectors miss things too, so drill slowly and stop straight away if you feel any resistance, smell burning, or see water. Know where your stopcock is (usually under the kitchen sink) so you can shut the water off fast if you ever hit a pipe, and if you have any doubt at all, isolate the relevant circuit at the consumer unit before drilling.