Fault finding

Fault finding is for problems where the cause is not obvious: an RCD that trips at random, a circuit that has gone dead, lights that flicker, or a breaker that trips as soon as you reset it. Some faults are quick to trace. Others only show up in damp weather or when a particular appliance is running, and those take methodical testing. Craig starts with the questions that narrow it down: when it trips, what was running, and whether anything has changed recently, such as new appliances, building work or a leak. He then unplugs appliances and isolates circuits one at a time, and uses an insulation resistance tester to find where current is leaking to earth. Common culprits are a faulty kettle or washing machine, water in an outside light or socket, a nail or screw through a cable, or a failing joint in a junction box. Once the fault is found, we explain what it is and either repair it there and then or quote for the work if it is bigger. The cost depends on how long the fault takes to trace, which is why the detail you give us at the start matters. Before you call, note which breaker or RCD trips, how often, what was switched on at the time, and whether unplugging everything stops it. A photo of the consumer unit with its circuit labels helps.