[vinothkumar asaithambi]

Hi flint !!!

sorry for the delayed reply.Well bck 2 topic,
Yes, U r partially right. DB main breaker is 10kA rating and its branches will be 6kA. Where SDP with MCCB, 36kA rating and MDB ll have MCCB or ACB , 50kA rating. Upto this u r rite.

consider the fact, all the loads wont be connected. pls remember concept of Demand factor. According NEC tables D.F value for SDP (10 DB`s Connected) ll be 0.4 to 0.5. hence the incoming breaker for SDP = 100A(wont be 100A at all, lets consider for the calculation) x 10( no. of DB`s) x 0.4 = 400A.

For MDB level, Demand factor ll be reduced to 0.3 to 04, rating ll be

10(No. of. SDP`s) x 10(No. of. DB`s) x 100A x 0.3 = 3000A. from this we can easily size the transformer or Generator.

Hope u can under stand this calculation.

Dear Flint, i m just looking for some proper calculation for this kA ratings. if any like that, please share with me.

ThX n Advance,

Vinoth.

if something wrong pls correct me..

[vinothkumar asaithambi]

Thanks for ur reply my frnd..
But i gotta too many questions..you gonna answer them pls..
consider the case i am having 10 DB`s each having 100A incomer MCB..and these DB`S ll be fed from SDP(Sub distribution Panel). where this SDP and the some other SDP`s (consider same size, say 10 each) connected to the MDB ( Main Distribution Board.).
Consider this is a Domestic load and load voltage 230/400V, 50Hz.

Here is my Questions…

1. What Kind of Breakers we have to choose for each level(from DB- SDP – to MDB)??

2. What ll be the KA ratings for all these breakers (Incomer and Branches) ???

3. Is there any calculation behind this, choosing breakers and its KA ratings???

4.is there any Space Factors we have have to consider, when we are making all these panels???

5.Give me list of Busbar Sizes to carry all these for each level…

ThX n Advance,

[vinothkumar asaithambi]

Hi Megha!
Can u send me some reference materials for LT switch borad design?
vinotbe@gmail.com dis s my mail id.

Thx n advance

[vinothkumar asaithambi]

Hi Guys! i have the basic knowledge about LT Switch Boards & Control Panels. But i want to know about KA rating in selecting the Breakers & Panel Sizing, Can you provide me a piece of idea on this???

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