S7. Why does the MCB on the Dimmer Trip sometimes when a lamp fuses.

1. Fusing of Tungsten Halogen Studio and Theatre Lamps
   
2. A lamp normally fails at end of Life by fusing of filament. Often an arc then forms and as there is little resistance to limit the  current, this rises to a very high value which if maintained can result in a serious overload.
   
3. A quick acting high breaking capacity MCB or fuse connected in the supply line of the dimmer disconnects the supply when this occurs