LED Track light powered from two sources.

[khatus]

Here two circuits from Lighting DB 2(LDB2) R4 and R5 are given in one track(track lighting). My question is can power be supplied from two separate mcbs from one DB to the same point (i.e to the same load).

[jwet]

I'm not an expert but seeing no replies, I'll give you my opinion.  Perhaps wiser men can chime in and correct me.

If I understand it correctly, it doesn't sound right.

I guess the designer wants to able to have all lights on one MCB and a few others on a secondary MCB for house lights and dimmed lights. It marginally OK if the two MCB are interlocked so they can be on at the same time but if they are both powered it creates some real problems- here are a few.

1. Worst case, if using 110v circuits, the two could be from opposite legs across neutral and paralleling them directly short the 220V combination.
2. Even small drops in voltage caused by different loading on the two legs could cause large currents to flow in unintended directions
3. It creates a hazard for a future electrician that disables the circuit at a breaker only to find its fed by the other.

If you have separate control of the coil and load circuit of the MCB, (like a relay) and you used only one source, it would get rid of all 3 of my objections.

[Towger]

Certainly not in my country and I assume the same in others.
There is a safety/confusion issue when isolating the circuits on the MCB(s).  What ever about different phases etc. 

[Gregg]

Look at the legend; upper right in the larger drawing. It shows the track to be 3 circuit track.  In another page or a detail it probably shows which circuit feeds which track.  All of the lighting may originate from a lighting control panel.