|Your house wiring is protected either by fuses or circuit breakers depending on the type you have.
Why do fuses/circuit breakers fail?
A fuse is a very important part of your wiring. The fuse will blow or the breaker trip when either:
The circuit is overloaded so that it is trying to draw too much current.
There is a fault on the circuit probably creating a short (short circuit) caused possibly by the live touching neutral or earth wires, or possibly a fault on an appliance.
When a fuse blows are a breaker trips It may be from a temporary problem so you can try changing the fuse (or fuse wire) or reset the breaker. If it then blows/trips again you still have a fault. Unless there is an obvious solution you should call a qualified electrician. See also my section on fault finding.
E.g. Sometimes when a light bulb fails it also trips the breaker and simply resetting the breaker will solve the problem.