First, Identify Which Switch Has Tripped
Usually, one protective device inside the consumer unit has switched off. You may still call it the fuse box, but identifying the device gives an electrician more useful information than saying the whole board has tripped.
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The IET explains the distinction between residual-current protection and devices that also provide overcurrent protection in its guide to RCDs. Read labels only from outside the enclosure; do not remove the front cover to identify a switch.
Common Reasons a Consumer Unit Keeps Tripping
Too much demand on one circuit
Using several high-power appliances together can overload a circuit and operate its circuit breaker. Note what was running when the power went off. An overload and an earth-leakage fault are different problems, so the device involved matters.
A faulty appliance
A damaged lead or an internal appliance fault can trigger a trip. If it consistently happens when one appliance starts, stop using that appliance until it has been checked. Do not repeatedly reconnect it to reproduce the fault.
Moisture or damaged wiring
Water in an outdoor fitting, damaged cable insulation or a faulty socket can allow current to take an unintended path. A connection with wet weather or a recent leak is useful information, but it does not confirm the source. Keep away from wet electrical equipment.
A short circuit
A short circuit can cause a breaker to operate immediately. However, an immediate trip alone does not identify the fault: an RCBO can also respond to earth leakage. Leave a circuit that trips again straight away switched off.
A problem with the protective device
The device itself can develop a fault, but it should not be blamed before the installation is checked. The IET's explanation of RCD testing notes that connected equipment and installation conditions can affect test results.
Why Does It Trip With Appliances Unplugged?
Unplugging accessible portable appliances does not disconnect everything in the installation. Fixed equipment, wiring and electrical accessories may still be involved. Persistent tripping therefore needs testing; it is not proof that the RCD needs replacing.
If several rooms lose power together, they may share one RCD. If only one breaker trips, record the circuit label and which lights or sockets stop working. Neither pattern, by itself, confirms which component has failed.
If the consumer unit stays on but the heating has stopped, that is a different symptom. Our guide to no heating or hot water covers the heating-side checks separately.
What Can You Safely Check?
Collect observations without opening or dismantling anything. Only approach equipment if the area is dry and there are no signs of burning, damage or exposed wiring.
- Read the label beside the switch that has operated.
- Note which parts of the property have lost power.
- Record what was in use immediately before the trip.
- Switch off and unplug accessible portable appliances where safe.
- Look at unplugged leads and plugs for visible damage, without opening them.
- Mention recent leaks, electrical work or newly connected equipment.
HSE's guidance on checking electrical equipment explains why damaged or suspect equipment should be taken out of use and checked by a competent person.
Do not keep resetting a recurring fault. Do not hold a switch on, bypass protection, fit a higher-rated breaker or remove the consumer unit cover. If you are unsure which switch has operated, leave it alone and seek help.
When Does Tripping Need Urgent Attention?
Stop trying to restore power if there is a burning smell, scorching, smoke, crackling, obvious damage or water near electrical equipment. Do not touch a socket or consumer unit to check whether it is hot.
London Fire Brigade identifies hot plugs, scorch marks and breakers that trip without an obvious reason as warning signs of an electrical problem. Keep people away from suspect equipment and arrange urgent professional help. If a fire starts inside your home, get out, stay out and call 999 as soon as it is safe.
How Is the Cause Found?
An electrician uses the symptoms, inspection and suitable electrical tests to distinguish an appliance fault from a problem with wiring, accessories or protection. Describe when the trips happen, including intermittent faults that have stopped by the time help arrives.
HSE recommends inspection and testing by a competent person to establish whether an installation is safe. A reset that restores power does not provide that assurance.
For recurring faults in London, our electrical service is the relevant next step for investigation and repairs.
Does the consumer unit need replacing?
Not necessarily. A protective device may be working correctly and responding to a fault elsewhere. The repair should follow the findings. An appliance, accessory or section of wiring may need attention; replacement of the consumer unit requires a separate assessment of its condition and protection.