New light switch keeps tripping breaker? It’s possible that the new light or switch is faulty from the manufacturer. Other potential reasons why this is happening include the electrician installing the light switch incorrectly or causing a fault in the existing electrical system. My post will attempt to explain what is happening and what you can do about it.
How A Light Switch Works
A light switch is typically wired in the following configuration. The light switch will have an incoming ‘live’ wire from another switch or the switchboard. This live wire then proceeds to the light. The light will also have a neutral and earth wire.
Why Would A New Light Switch Cause A Breaker To Trip?
Electrical circuits have the potential to either cause fires or give people electric shocks. A breaker is a protection device and its job is to trip whenever the risk of this occurs.
In the home, there are three reasons why a breaker will trip.
Short Circuit
A short circuit, as its name suggests, happens when the electrical current takes a ‘short path’. This typically occurs when phase and neutral come into contact. The result can be a pop, buzz, crack or something much bigger, eventually leading to a fire if the breaker doesn’t trip.
Overload
An overload will occur when there are too many lights on a circuit. In effect, they have overloaded what the wire can handle, causing the wire to heat up and eventually causing a fire if the breaker doesn’t trip.
Ground Fault
A ground fault is a type of short circuit when the live wire comes in contact with the earth or a conductive body. This leads to potentially fatal electric shocks if someone touches a conductive part of the component. A ‘RCD’ is the type of breaker used to protect against this.
Most of the reasons why a new light switch keeps tripping the breaker have to do with the different ways it might have been incorrectly installed. Here are some other reasons why the breaker might be tripping.
New Light Switch Keeps Tripping Breaker? – Reason #1
Installed Wrong
A simple mistake like transposing phase and neutral will cause an RCD to trip. This can happen at either a light switch or light fitting. The installer should check what they have done to confirm it is correctly wired and, most importantly, safe.
New Light Switch Keeps Tripping Breaker? – Reason #2
Overloaded Circuit
Have new lights been added to the circuit? If so the circuit might have been overloaded. This will cause the breaker to trip because the circuit isn’t rated for it. This is common in older houses where smaller gauge wire was often used.
It is also possible that the circuit breaker is rated quite low or possibly too low for the circuit. If so, it is a good idea to inquire why that is with the installer. There could be a reason why.
New Light Switch Keeps Tripping Breaker? – Reason #3
Disturbed Something Faulty
Was the installer in your ceiling? It is possible a cable or fitting was disturbed in the ceiling which is now causing a fault. In my experience, ceiling spaces can sometimes contain dodgy cables and fittings that can lay dormant until disturbed by someone crawling around in the ceiling.
New Light Switch Keeps Tripping Breaker? – Reason #4
Faulty Component From Manufacturer
The next possible reason is that the switch or light fitting is faulty from the manufacturer. In our experience, faulty switches and light fittings are relatively common, especially if cheaper brands are used. In this case you should be able to consult the warranty for a refund or replacement.
Conclusion
New light switch keeps tripping breaker? This is most likely due to the installer making a mistake like wiring the switch wrong, overloading the circuit or messing with existing wiring causing a fault. Of course, it could also be caused by faulty components. The best thing to do is politely discuss with your installer what might have gone wrong.
We Fix Faults is a blog obsessed about finding and fixing common household electrical faults. If you found this content useful please subscribe to our mailing list or sharing this post is highly appreciated.