How to calculate busbar size & what is the procedure we
make for determine that?
Question Submitted By :: Electrical-Engineering
I also faced this Question!! Answer Posted By
Usually busbar sizes selection depends mainly on two
factors. Which is current + temperature. The size which you
are going to select must carry the current you need and
must not create much heat which excess the limits.
Our formula , we use 1.5 A / 1 sqmm. Khan
we need to consider short ckt(KA) also. Say short ckt level
is 20KA then we need to select busbar accordingly. Md.mahmudul Hasan
Please Give the references........otherwise its very
CURRENT DENSITY OF CU=1.2A/MM2
CURRENT DENSITY OF AL=.8A/MM2
FOR EX: DESIGN REQUIREMENT OF 400A MAX.CAPACITY.
CONSIDER THE BUSBAR IS CU.
AREA OF THE BUSBAR=400A/1.2=333.33MM2
APPROX. VALUE= 350MM2
SO THAT, THE STANDARD SIZE IS 50MMX8MM Santhoshsasidharan
The bus bar size normally for copper 1sqmm=1.25Amp and
aluminium is 1sqmm=0.8Amp Dubai
I want to ask to vijay that is there any relation between
current denesity of copper and material purity.
also is ther any standard which defines the standard
current denesity of material. Gajanan
We have consider so many factors to calculate Busbar sizing.
a) Current carrying capacity : for that Copper can go upto
1.6A/Sq.mm and Aluminium is 1A/Sq.mm
b) Ambient temp. and temp. rise to considered.
c) Heat loss to be considered.
d) Short circuit current to be considered. Renukaswamy
Aluminum current transfer capacity :0.8 amps/sq mm
Copper current transfer capacity :1.6 amps/sq mm
x= 640 / .8 = 800 sq mm
800/10 (Say 10 mm Width)
L=80 MM, W=10 MM Jk
simply the dinesty of the copper equal 2A/mm2 or 1.5A/mm2
accprding purity of the substance so using mentioned
formula to get size of bus bar . Karim Halawa
Thumb rule for copper is 1.25 Amps per sq.mm and for Aluminum 0.8 amps for sq.mm