Electrical fault finding and repairs

A good share of tripping problems are a faulty appliance rather than a faulty circuit, and you can narrow that down yourself in ten minutes.

1. Unplug everything on the affected circuit, including things that live plugged in, like chargers, extension leads and the garage freezer.
2. Reset the breaker or RCD. If it holds, plug items back in one at a time, leaving a few minutes between each.
3. The item that trips it is your culprit. Kettles, immersion heaters, washing machines, outside lights and old extension leads are the usual suspects.

The aim is to find the cause, not to replace things until the symptom goes away. That's the difference between a repair that lasts and one that comes back in a fortnight.

1. Talk it through: when it happens, what's running at the time, what changed recently. This narrows things down faster than any meter.
2. Split the installation and test circuit by circuit: insulation resistance, continuity, loop impedance, RCD operation.
3. Divide the failing circuit down at a junction box, a socket or a light, until the fault is bracketed to a section.
4. Repair, retest, and record what was found and what was done.

• Water. Outside lights, garden sockets, a leaking shower tray above a ceiling rose, a bathroom extractor. Faults that only happen after rain are almost always this.
• A nail or screw through a cable, often traced to a shelf, a curtain pole or a new floor put down months ago.
• Failing appliances, particularly heating elements: kettles, immersion heaters, washing machines, tumble driers.
• Loose connections at a socket, switch or junction box, which show up as flickering, intermittent loss and localised heat.
• Cumulative leakage: several appliances each leaking a small amount to earth, adding up to enough to trip a single whole-house RCD. Common on older boards, and one of the arguments for individual RCBOs.
• Rodent damage in lofts and outbuildings.

Being straight about this: KS Electrical is a small local business, not a 24-hour call centre, so we can't promise a fixed emergency response time. What we can do is answer the phone, tell you honestly when we can get to you, and talk you through making it safe in the meantime.

• Right now: burning smells, smoke, visible scorching, water getting into electrics, any electric shock however small.
• Same or next day if we can: total loss of power, a breaker that won't reset, no heating or hot water.
• Can wait: a single dead socket, an outside light out, a circuit you can work around.