Short in Circuit, Bad Breaker, or Floating Neutral?

Some where on that circuit there is a bad neutral. You should not have to add the wire to it? Did you nail in something to wall and then it happened (*maybe nicked the neutral)?

Neutral wire could have broken.
Wire nut could have come loose in junction box.
Is the line overloaded? running too much stuff.
Ria

You had an electrician fix it and he connected 4mm wire between the neutral and the earth. All was well for 2 days, then it kept tripping whenever you pulled out the wire. What could be the problem? Maybe pulling out the wire is the problem.

If it was fine for two days after he did this, maybe it wasn't meant for you to keep pulling the wire out?

I don't know that much about electricity, but call the electrician back to fix the problem. They are supposed to guarantee their work.