DG Cable

What voltage?
What ambient temperature?
What type of insulation on the cable?
3-core cable, separate cables, all cables in one conduit/raceway?
Any other conductors in the same conduit/raceway?
What code are you following?

Voltage-415, Delhi ambient tem-42degree C

insulation -XLPE

If 3 or 3.5 core--

If single core---

In trench

No conductor cable except control cables,

Indian standard

Excellent; that is the information needed to proceed further.

750,000 VA/(415√3) ≈ 1043 A; this is the most critical number. For continuous duty, you may need to multiply by 1.25, giving 1304 A. If you use cable, I think you will need to parallel at least 3 or 4 cables (unless you do this with bus bars).

I am not familiar with IS (India Standard), but in the U.S. NEC (National Electrical Code) there are several tables giving the allowable current for various conductor sizes and types and insulation temperature ratings. You must take care in consulting the correct table for the conditions. If you use multi-core cable, each cable should contain all 3 phases.

I have only hit a few high spots here, so please consider this as just a start. I don't have a code book in front of me, and thus can't go much further at the moment.

if i use as suggested by dg vendor 3.5C,300sqmm xlpe cu condutor with armoured as under:

R, Y , B & N Cores of Cable-1 will get terminated to Terminal "R" of the generator,

R, Y , B & N Cores of Cable-2 will get terminated to Terminal "Y" of the generator,

R, Y , B & N Cores of Cable-3 will get terminated to Terminal "B" of the generator,

R, Y , B & N Cores of Cable-4 will get terminated to Terminal "N" of the generator,

I may go for bus bar what the distance between DG and Panel is 100Mtr.Approx

Lets suggest

Why not keep it simple:

• All the reds to the R terminal
• All the yelows to the terminal
• All the blues to the terminal
• All the Ns to the N terminal

?

Please get a more knowledgeable vendor. PW Slack is correct; we have said the same basic thing in two ways.

You already posted this under "Cable Sizing". In my opinion 4 cables of the size you give will be adequate if they are well spaced apart and on a perforated tray, in the open and protected from the sun. BUT using armoured cables with only one phase in them is BAD practice which will lead to overheating and failure. Use the "three core and neutral" cables with all 3 phases and a neutral in each cable as they are intended to be used - you will not be buying any more cables than proposed. Also, as one correspondent noted, extra copper is wasted on the neutral, that is why the neutral is half the section.