Why do my lights keep blowing?

why do my lights keep blowing?

This is what a customer asked before we found the fault under a floor in their bathroom.

Fault finding, as us electricians know, is not always the easiest of tasks. We found this fault under a floor in a bathroom, infact under the bath, it was not the easiest of places to get too! As you can see the cables were damaged and burnt causing the mcb (miniture circuit breaker) to trip.
The cables were infact inside the hole in the joist and it was just by chance that I happen to see that the cables looked far too tight and gently pulled them to find the fault.

This is why I always make sure that when I drill a hole in a joist it will be big enough to take my cables I am about to run, or drill another. Its a shame when the person wired this they did not do the same, then this probably would have not happened!