So finding out the reason behind “why your lights or light is flickering” could take some time, but there is an easy way to pinpoint the cause of your fault by using a little bit of common sense. For instance, if you have a single flickering light on a bank of spotlights that are controlled by one switch, the cause of the fault will be located around that fitting. Things to check are: the light fitting itself, the lamp or bulb could be damaged or just poor quality, the transformer (if a low voltage light) or a loose connection supplying the fitting. If all the lights are flickering, then you most probably have an issue with something controlling the whole circuit, this could be a fault with the light switch, the MCB supplying the the live feed to the circuit, or a loose connection with the cable supplying the first light on the circuit.
If you have a florescent light or a bank of florescent lights that are flickering, use the same method shown above to try and diagnose the fault. A very common a reason for these light not working or flickering is: the fluorescent tube is burning out (check for dark areas on the lamp), or the electronic starter located at the side of the fitting is a fault, these are two of the most common faults. Also note that if you have a large bank of florescent lights they maybe energised via a relay, so this could be another place to inspect.