Lighting MCB tripping from time switch

I have the lights to come on with a timeswitch and every so often the lighting circuit 16A MCB trips. Everything is fine when turning lights on 1 by 1.
The lights being turned on are as follows:
2 low energy 13w fluorescent bulbs.
3 50w gu10 halogen bulbs.
4 100w halogen bulbs.

However they can all be turned on at once usually its just in the morning or after they've been off for a while it trips but even then not always.
Please help ist here a short or is the MCB not a high enough rating?

Why 16A on lighting??

What size cable feeds those lights?

If it is 1.0milli, then you need to downrate the CPD.

100w halogens? What type are these?

16amp? Do you mean 6, or seriously 16?

A little more info required.

Also what type is the MCB? This will be written as a letter. Usually 'B' but possibly 'C' or 'D'