Separate Transformer in Lighting Panel?

Is secondary, connected to all the load distribution points? It will provide isolation from grid, since isolated from grid ground/neutral. Shock hazard will be eliminated. Generally used in hospital equipments wired to patients & service bench,

Good observation!

This is to reduce the fault level of the lighting circuit. Normally, one would use a very small cross section (of say, around 2.5 sq.mm Copper) for lighting circuits. If a transformer is not used, then, if there is a short circuit at a lighting point, the short circuit current supplied by a larger power transformer would not be tolerated by the small lighting wire and it would damage, even causing fire accidents. A suitably rated lighting trafo would reduce this fault level within the tolerance limits of the wire.

Other reasons could be better voltage regulation, isolation, etc.

Thnks for ur reply Mr.Electrical expert please elobarate me more sir...... iam not getting clearly the point......