when i turn on my garage lights they are starting to trip the main, not the light fuse in the garage or the garage fuse on the fuse board, but the main fuse before the fuse board.

the lights are flourescent, they start to come on then they go off, when i turn fuse back on the lights are fine.

thanks

Take the tubes or starters out one at a time to see if any particular one is causing it.

Are they taking the earth trip,in which case its probable water in one of the fittings.
Cheers,
Bob

If your main board is RCD protected then as suggested above it is more likely an earth fault rather than anything else. Check all of the connections to see if there is a loose earth wire anywhere.

Ditto above if your main trip switch is an rcd then it's more than likely an earth fault or water (or even just a dampness) in one or more of the fittings.

Can you smell burning Rat in there?