What is this?
When an electric boiler trips the electrics, it means there is an electrical fault within the boiler or its circuit that is triggering the protective devices in your consumer unit. This is a common issue with ageing boilers and typically worsens over time.
Common causes
- Failing heating element with deteriorating insulation — the most common cause
- Water leak inside the boiler reaching electrical components
- Earth fault in the boiler's internal wiring
- Faulty PCB or contactor
- Damaged cable between the consumer unit and boiler
- Incorrectly rated MCB for the boiler's current draw
Is it dangerous?
A boiler that trips the electrics has an earth fault or short circuit. The RCD is doing its job protecting you from electric shock. Do not bypass or tape up the trip switch. While not an immediate emergency, the fault should be investigated promptly as it could worsen.
Can I fix it myself?
You cannot safely fix this yourself. The only thing you should do is check whether the boiler trips the MCB (just the boiler circuit) or the RCD (multiple circuits). This information helps the electrician diagnose the type of fault.
When to call an electrician
Call an electrician as soon as possible. A boiler that trips the electrics will not fix itself and the fault is likely to worsen. If the boiler is tripping the RCD and taking out other circuits, treat it as more urgent.
What will an electrician do?
Isolate the boiler and test the circuit
Perform insulation resistance testing on the boiler's element and wiring
Check for water ingress inside the boiler
Test the heating element — the most common cause of tripping
Replace the faulty element, PCB, or other components
Typical cost
£120 – £400
Heating element replacement is the most common repair. If the PCB has also been damaged, costs will be higher. Very old boilers may not be worth repairing.
