Boilers have become increasingly electrical and less ‘analogue’ over the years. In fact, some older boilers have very few electrical parts at all.
However, if you own a relatively new boiler made in the last two decades, it’s likely to have at least some electrical components. External components like pumps are also electrically powered.
Boilers connected to the electricity can trip fuse boxes (RCD breakers) if there’s some sort of fault affecting the electrics. This is more likely for newer boilers with lots of electrical components.
So, why is your boiler tripping the fuse box?
Reasons why your boiler could be tripping your fuse box
Common causes of a boiler tripping the fuse box include:
- Faulty thermostat
- Faulty pressure relief valve
- Faulty pump
- A buildup of limescale in the system
- A wiring or electrical problem.
The first thing to do is shut the boiler off at the mains and disconnect it totally. Never fiddle around with electrical components unless you’re 100% sure that the boiler is powered down.
Your RCD switch tripped to protect you from electrical shocks or even a fire. It’s doing its job.
Once you’ve totally powered the boiler off (preferably by switching the main breaker off), you can investigate the cause of the short. You should unplug sensitive electrical devices like computers before switching the main breaker back on.
Here’s what to check for:
Your boiler is leaking
First, check for leaks. Any leaks can cause short circuits, which should trip the fuse box. This shuts the electricity down to prevent further damage or electrical fires. Leaks might precipitate from within the boiler itself, neighbouring pipework, or elsewhere external to the boiler (e.g. a damp cupboard).
Almost any water-damaged electrical component can cause fuse problems. For example, if the thermostat is faulty, it may cause the boiler to overheat and trip the fuse box.
This is probably the most likely cause of a boiler that regularly trips the fuse box, and will almost certainly require careful diagnosis and repair by a Gas Safe engineer. Do not continue to use your boiler if you suspect a leak. Read more about leaking boilers.
- Leaking boilers can cause all sorts of electrical issues that result in a switch trip or blown fuse.
- Suspected leaks should be fixed as soon as possible.
- Never attempt to inspect a leaking boiler without shutting off the electricity.
Faulty component within your boiler
Several components within the boiler might be causing the RCD to trip.
The thermostat is the most likely culprit here, as an issue in the thermostat will possibly cause the boiler to overheat and trip to switch.
The pressure relief valve is another candidate. This safety mechanism releases pressure when it gets too high, preventing the boiler from overheating and tripping the fuse box. If the pressure relief valve is not working properly, it may cause the boiler to overheat and trip the fuse box.
If the thermostat and pressure relief valve is working properly, then the next thing to check is the pump. Again, this might cause overheating if it’s not working correctly.
Finally, limescale build-up on the elements inside the boiler can cause electrical issues. A limescale-ridden boiler might overheat or generally cause strange issues that affect performance.
- Faulty thermostats can trip switches by overheating the boiler.
- Broken or failing pumps can cause electrical issues.
- Limescale build-up within the boiler is another probable cause.
The wiring is faulty
Any wiring issue can cause an electrical short. This is true of the wiring inside the boiler, and the wiring connecting it to the mains.
Some boilers have 3-prong mains connectors plugged into a mains socket. If this is the case, check the 3-prong plug to see if the fuse is intact, and check the mains socket by plugging something else in to see if it works/blows immediately.
The boiler is fitted with its own fuse that will likely blow in the event of an electrical fault. Sometimes, a partially blown fuse will continue to work while causing shorts.
Finally, you should check the wiring to ensure it is all connected correctly and that no wires have become loose or melted. Corroded wires are a sure sign of a leak.
- Any wiring issues can trip the fuse box.
- Wet, corroded or melted wires and connectors are regular culprits.
- Never mess around with wiring unless you’ve shut off the electricity.
Is a boiler tripping the fuse box an emergency?
The fuse box prevents it from being an emergency. The fuse box is working as it should by shutting the electricity off to prevent further damage, electrical shocks or fires.
Your electrical appliances don’t like to be shut off suddenly and switched back on without being switched off at the plug first. Likewise, sensitive devices like computers will suffer if you keep switching your breakers back on.
Unplug expensive electrical devices before switching your breakers back on to prevent damage.
If a leak or overheating problem is causing the trip, you shouldn’t delay calling one of our Gas Safe engineers.
Leaks can cause catastrophic damage to electrical components and should be repaired as soon as possible.
How to fix your boiler tripping the electrics?
If you are still unable to identify the cause of the problem, it is best to contact us to diagnose and repair the issue.
Never take any risks with a suspected electrical issue. Electrical boiler problems can be serious, and a small fault can quickly develop into a catastrophic issue that is expensive to fix.
Our engineers will be able to determine the exact cause of the problem and advise you on the best course of action. In some cases, they might need to work with an electrician to diagnose the issue.
In summary, if you turn your boiler on and it trips the fuse box or RCD breaker, then you should consider calling a Gas Safe engineer.
Contact us today if you’re experiencing this problem - we’ll help you get to the bottom of it!
