What to do if your boiler is tripping the electrics

31 March 2024

A well-functioning boiler is your home’s workhorse, providing hot water for washing, baths and heating systems. It’s especially vital during colder months. One problem that can disrupt this is when your boiler starts tripping the electricity in your house – and it’s guaranteed to happen at the most inconvenient moment possible!

You might hear the circuit-breaker in your consumer unit (often known as a fuse box) snapping open. When you open the box, you’ll see that one of the RCDs (residual current devices) has its switch flicked the opposite way to all the others, or on some occasions the master switch might trip and all your home’s electrics are tripped out.

This article will guide you through why this happens and what can be done about it.

How a gas boiler uses electricity

Gas or oil-powered boilers use electricity to power various components such as the ignition system, the pump which circulates water around radiators or underfloor heating systems, and controls like thermostats and timers.Therefore, faults or malfunctions within these components can lead to the entire system tripping your home’s electrical supply.

10 Reasons why the boiler might be tripping 

Understanding why a boiler might be tripping the electricity in your home can help pinpoint the problem more efficiently. Here’s a detailed look at what could be causing the issue.

  1. Faulty heating elements: In electric boilers, the heating elements are crucial for warming up water. Over time, repeated expansion and contraction from heating cycles can lead to wear and tear, causing them to fail or burn out. A short circuit can occur if these elements partially or completely earth themselves.
  2. Water leaks: Water should never come into contact with electrical components, but leaks within the boiler system can lead to exactly that. This can happen due to corrosion, poor connections or damage to pipes or the boiler itself, leading to short circuits when water and electricity mix.
  3. Pump failure: The pump keeps water circulating through your heat distribution system. If it gets stuck or the motor fails, it may draw excess current trying to overcome the blockage or fault, causing your electrical system to trip in response to the overload.
  4. Control panel faults: Modern boilers have control panels that manage operation timing and intensity. Any malfunction within this panel, such as short-circuiting due to moisture exposure or wiring issues, can trip your electricity as a safety precaution.
  5. Faulty thermostat: A thermostat regulates the boiler’s heating temperature. If it’s defective, it may incorrectly gauge temperatures causing the boiler to overheat. Many systems have built-in safety functions to cut power under such conditions to prevent damage or risks, but it could also trip the whole circuit.
  6. Wiring issues: Electrical faults can arise from several wiring issues such as deterioration, incorrect installation or even rodent damage. Short circuits or earth faults in boiler circuitry often result from exposed, damaged or loose wires.
  7. Damaged insulation: Electrical wires are coated with insulation to prevent unintended currents. Over time, this insulation can get damaged due to heat, mechanical stress or chemical corrosion, potentially leading to leakage currents that trip your electricity.
  8. Overheating boiler: Lack of maintenance can lead to a buildup of sludge and scale inside the boiler, which hampers heat transfer and leads to overheating. Modern boilers have safety mechanisms that detect overheating and shut down the system by tripping the electrical supply to prevent damage.
  9. Pressure problems: Boilers operate within a specific pressure range. Too high or too low pressure can cause the system to shut down as a protective measure. Sudden pressure drops or increases can trigger safety features that might include tripping the electricity supply to prevent operating under unsafe conditions.
  10. Circuit load: Sometimes, the issue might not solely lie within the boiler itself but with how much power it draws from your home’s electrical system. If your boiler shares a circuit with other high-demand appliances or if the circuit cannot provide enough power for operation, it may trip as it exceeds safe limits.

Could the consumer unit or RCDs be faulty?

When troubleshooting a boiler that’s tripping, consider all possibilities, including issues unrelated directly to the boiler itself. One often overlooked cause could be the consumer unit or the RCD within it that protects the boiler. Depending on how it was installed, it might be on its own circuit, or it could be part of another circuit (e.g. downstairs sockets). These components can also cause problems if they malfunction.

Understanding consumer units and RCDs

A consumer unit is the heart of a home’s electrical system, distributing electricity from the mains supply to various circuits around the building. It contains circuit breakers, which protect each circuit from overload, and one or more RCDs. The RCDs are designed to rapidly cut off the electric supply if they detect an imbalance between the live and neutral wires, such as when electricity is flowing to the earth through a person who has touched something live or through a water leak.

Signs of faulty consumer units or RCDs include:

  • Frequent tripping for no apparent reason: If your RCDs trip frequently and you cannot identify an appliance or system fault, including your boiler, this could suggest a problem within the consumer unit itself.
  • Unresponsive RCDs: An RCD that fails to reset or is difficult to reset might indicate an internal fault.
  • Visible damage: Signs of wear, corrosion or damage within the consumer unit can point to malfunctioning.
  • Burning smells or noises: A burning smell or unusual buzzing noise coming from your consumer unit could signal serious issues that need immediate attention.
  • Age: Older consumer units may not meet current safety standards and can become unreliable over time due to degradation of components.

Why consumer units and RCDs may fail

Consumer units and RCDs might fail for various reasons:

  • Age and wear: Over time, electrical components degrade. Older units aren’t always compliant with modern safety standards and might lack the sensitivity of newer models, leading to either too much sensitivity (tripping too easily) or not enough (not providing adequate protection).
  • External damage: Exposure to moisture, physical impact or pests can damage sensitive components, causing malfunctions.
  • Poor installation: If a consumer unit or its components were not installed correctly, this might lead to issues. Incorrect wiring or loose connections can cause RCDs to trip erratically.
  • Overloading: Overloading a circuit beyond its capacity can cause component wear or damage more quickly than normal.  

What to do

If you suspect that the consumer unit or RCDs may be faulty:

  • Initial checks: Ensure no obvious issues could be causing the tripping, like overloaded sockets or circuits.
  • Professional assessment: Consider hiring a certified electrician to perform a comprehensive assessment of your consumer unit and electrical installation. They can conduct tests to determine if your RCDs are functioning correctly.
  • Upgrades or repairs: If issues are found with your unit or RCDs, it might be necessary to get an electrician to replace faulty components or upgrade your entire consumer unit to comply with current regulations and enhance safety. Remember that everything up to and including the electricity meter is your supplier’s responsibility. After that (starting with the fuse box/consumer unit) it becomes your responsibility.

Remember, working with electrical systems can be dangerous. While homeowners can perform basic checks and troubleshooting, any work related to the consumer unit, RCDs or internal wiring should always be carried out by a qualified professional electrician who knows how to handle these components safely and in accordance with local building codes and standards.

What to do when the boiler trips repeatedly

If your boiler trips occasionally, it might be a random event caused by a power surge or such like. However, regular occurrences signal a deeper issue that requires attention. First, investigate simple causes like other overloaded circuits or defects in visible wiring connected to your boiler. Next, try resetting your RCDs and check if that resolves the issue before proceeding further.

If the tripping continues:

  • Ensure there are no immediate hazards like water leaks.
  • Check if your boiler displays any fault codes.
  • Attempt a boiler reset if safe – follow your manufacturer’s manual.

Call the experts

When your troubleshooting efforts do not resolve the tripping, it’s crucial to bring in professionals. Our certified boiler service and repair specialists can provide a comprehensive examination, diagnose underlying issues, and carry out necessary fixes safely and efficiently. We have expertise in all areas from electrical faults to mechanical failures within boiler systems.

The importance of regular servicing

Regular servicing by qualified professionals is very important. It’s not only essential for ensuring your boiler operates safely and efficiently but also plays a critical part in preventing unexpected breakdowns – including those causing your electricity to trip. 

Checks typically include cleaning key components, identifying wear and tear early, checking for leaks, testing functionality and ensuring no parts are likely to fail soon. An annual service is also probably a condition of your warranty remaining valid. In short, it’s worth doing every year, and usually takes less than an hour to complete.

Call the experts

Our boiler specialists can quickly diagnose any issues with your boiler that need repairing. If it’s a wider electrical issue, we can at least rule out the boiler, and possibly point to the issue that needs professional attention. Please get in touch if your electrics are being tripped and you suspect it’s because of the boiler, or call our Milton Keynes plumbers directly on 01908 631704.