Cost Breakdown
| Item | Min | Max | Note |
|---|---|---|---|
| Diagnostic visit (first hour) | £80 | £150 | Callout plus first hour of investigation and testing |
| Additional hours | £40 | £70 | Per hour if the fault requires extended investigation |
| Thermal imaging survey | £100 | £200 | Identifies hotspots in wiring, connections, and consumer units |
| Circuit testing | £60 | £120 | Insulation resistance, continuity, and earth fault loop impedance tests |
| Repair (simple fix) | £30 | £80 | Tightening a loose connection, replacing a damaged socket or switch |
| Repair (complex fix) | £100 | £350 | Replacing a section of damaged cable, faulty RCD, or degraded circuit |
What's Included
- Visual inspection of the consumer unit, circuits, and accessible wiring for obvious damage or signs of overheating
- Electrical testing using calibrated instruments including insulation resistance, continuity, RCD trip time, and earth fault loop impedance
- Systematic isolation of circuits to narrow down the fault location
- Clear explanation of the fault found, the cause, and recommended repair options with estimated costs
Factors Affecting Cost
- Complexity of the fault: A loose connection at a socket may be found in minutes, while an intermittent fault on a buried cable run could take hours of systematic testing to locate.
- Accessibility of wiring: Faults in exposed wiring or accessible loft spaces are quicker and cheaper to diagnose than those hidden behind plasterboard, under floorboards, or embedded in concrete floors.
- Age of the electrical installation: Older properties with outdated wiring (rubber or lead-sheathed cable, no earth, rewireable fuses) tend to have more complex and harder-to-trace faults.
- Number of circuits affected: If the issue is isolated to a single circuit, diagnosis is faster. If multiple circuits are affected or the problem is at the consumer unit, more extensive testing is required.
- Time of callout: Standard weekday rates are cheapest. Evening, weekend, and bank holiday callouts typically carry a premium of 25-50% on the hourly rate.
- Whether repair is included: Some electricians include minor repairs in the diagnostic fee, while others quote separately for fault finding and repair. Always clarify upfront.
- Location: Electricians in London and the South East tend to charge 20-30% more than those in the Midlands, North, or rural areas.
How Long Does It Take?
Most electrical faults can be diagnosed within 1-2 hours. Straightforward issues like a tripped RCD caused by a faulty appliance or a loose terminal can often be identified and resolved within an hour. More complex intermittent faults, such as a cable with damaged insulation that only faults under load or when damp, may require 2-4 hours of systematic testing. In rare cases involving hidden wiring in older properties, the electrician may need to return for a second visit with specialist equipment such as a cable tracer or thermal imaging camera. If a repair is straightforward, the electrician will usually carry it out on the same visit.
Do I Need This?
You should call an electrician for fault finding if you are experiencing any of the following: an RCD or MCB that keeps tripping, complete loss of power to a circuit or the whole house, flickering or dimming lights, burning smells from sockets or switches, scorch marks on outlets or the consumer unit, electric shocks from appliances or metalwork, or any other sign of an electrical fault. Electrical faults can be dangerous and should never be left undiagnosed, as they can cause fires, electric shock, or damage to appliances. Do not attempt to investigate electrical faults yourself beyond checking whether an appliance is causing a trip. If in doubt, call a qualified electrician.
How to Save Money
Before calling an electrician, unplug all appliances on the affected circuit and try resetting the trip switch. A faulty appliance is the most common cause of RCD tripping and costs nothing to identify.
Book during normal weekday hours (8am-5pm) to avoid evening and weekend premium rates, which can add 25-50% to the bill.
Ask upfront whether minor repairs are included in the diagnostic fee. Some electricians will fix a loose connection or swap a faulty socket at no extra charge during the visit.
If your installation is old and you are experiencing recurring faults, consider investing in a full EICR instead. This provides a comprehensive assessment of your entire electrical system and may be more cost-effective than multiple individual fault-finding visits.
Get two or three quotes if the fault is not urgent. Prices vary significantly between electricians, and a more experienced fault-finder may locate the issue faster, costing less overall despite a higher hourly rate.
Average Cost Summary
£80–£250
Typical price range for electrical fault finding cost in the UK. Prices may vary based on your location, property type, and specific requirements.
