I have custat rank of 5137 . will i get a seat in cusat Ernakulam in civil or Mech or in Electerical

I found it hard to get CS (All India Merit) at Thrikkakara Campus with 5887 Rank during Centralized allotment. But the general waiting list is 235 (All India Merit) and 315 (State Merit). Considering this and the demand for Electrical (there's EEE and ECE, I don't know which one you're referring to but for both) is less than that of CS, and my rank being way lower than yours and ongoing allotments in KEAM and JoSAA, yes there is a good possibility. Try the spot allotments if you haven't received seats in centralized allotment. And keep an eye on the waiting lists.

I had OEC/DHV reservation btw. I can't really confirm anything now, but I think many will opt for KEAM and JEE based colleges and the numbers will reduce further.