Busbar Size Calculation

Seriously how did you come up with the 250A MCCB?

Is the temperature outside or inside.

I'd do some research before you ask further question about busbar sizing. Its all over the net and lots of info in CR4.

Go get it!

"So what will be Busbar Size for Above Specification?"

I see gibberish, not a specification.

Try doing some work on your own.

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I do agree with Mr Sridhar.Many consultant without any application of mind , they simply indicate SC rating of 50 kA for the board and devices.

There will not be fault flow current to the extent of 50 kA in any normal circuit,

If 250 A MCCB happens to be incomer from transformer of 415 V , then transformer capacity should be less than 175 kVA.The %Z of this transformer will hardly be 4%.Then the prospective fault current will be 25 times the full load current which will be hardly be 7 kA.

Even if you assume this 250 A MCCB is incomer for sub Board, then there will be impedance of the cable which will restrict the flow of fault current and it will not be to the extent of 50 kA, unless this board is located in the Power Station.

Of late what is happening is many consultants simply say system fault level as 50 kA, and big Electrical Project executors ( L&T,Siemens,ABB,Schneider) and others request the switch board fabricators to design the boards for 50 kA irrespective of the location of the board in the Electrical system.

Duplicate thread, Mildred.