What is this?
When your consumer unit trips with nothing plugged into any socket, the fault is in the fixed wiring of your home rather than in an appliance. This means there is a problem with the cables, connections, switches, or fittings that are permanently wired into your circuits. This is a more serious situation because the fault cannot be resolved by simply unplugging something.
Common causes
- Damaged cable insulation due to age, heat, or physical damage
- Loose connection at a socket, light fitting, or junction box
- Water ingress into a junction box, ceiling rose, or wall-mounted fitting
- Nail or screw driven through a cable during DIY or building work
- Rodent damage to cables in lofts, under floors, or in cavity walls
- Degraded wiring in an older property that has reached the end of its lifespan
Is it dangerous?
This is a high-priority fault. Wiring faults can cause electrical fires and are not resolved by simply avoiding the circuit. The damage may be getting worse over time, especially if caused by water ingress or overheating. The fault exists whether the circuit is energised or not, so it needs professional repair.
Can I fix it myself?
There is very little you can do safely with a fixed wiring fault. You can try isolating individual circuits at the consumer unit to narrow down which circuit has the fault, but the actual repair must be carried out by a qualified electrician. Do not attempt to access junction boxes or open fittings unless you have isolated the circuit and are competent to do so.
When to call an electrician
Call an electrician promptly. A wiring fault that trips the consumer unit with nothing plugged in needs professional diagnosis and repair. If you notice any burning smell, discolouration of sockets or switches, or warmth from any part of the wiring, treat it as urgent.
What will an electrician do?
Carry out a systematic circuit-by-circuit isolation to identify the faulty circuit
Perform insulation resistance testing (megger testing) to measure fault severity
Use a process of elimination to locate the fault on the circuit — splitting it at junction boxes and sockets
Inspect the wiring route for physical damage, water ingress, or rodent damage
Repair or replace the damaged section of wiring
Recommend an Electrical Installation Condition Report (EICR) if the wiring is old and may have further faults
Typical cost
£120 – £300
Fixed wiring faults take longer to diagnose because the fault location must be traced. Costs increase if cables need replacing within walls, floors, or lofts.
