What is Bus Bar and how to calculate bus current carrying capacity

Busbar is defined as conductor or group of conductor used for transferring the power supply from incoming feeder and distribute them into outgoing feeders.

In other word,  it is type of electrical junction in which all the incoming and outgoing current meet.

Busbar are available in aluminium, copper, steel, iron, gold, silver etc..

But we are mostly using the aluminum and copper made busbars.

Bus bar are coming in market at different sizes

Like 20x4mm,20x6mm,20×10mm,25x5mm,25x6mm,25x10mm,30x10mm,40x10mm,80×8mm,100x10mm etc..

Let us discuss on current carrying capacity of bus bars..

Aluminium:

There is a thumb rule to calculate current carrying capacity. 

CCC = area of bus bar x 0.8 

Example:

We consider the bus bar size as 100x10mm,where 100mm is width of busbar and 10mm is thickness of busbar.

To calculate area,we need to multiply both w and t .

Area =100×10=1000Sqmm...

Now apply this area into above our thumb rule,

CCC= 1000×0.8=800A ..

So the current carrying capacity of aluminum busbar will be 800A ..

Copper:

Here the thumb rule is area of busbar x 1.4A.

We use the same busbar size I.e 100x10mm

We have already calculated the area .

So CCC =1000×1.4=1400A

So the current carrying capacity of copper busbar willbe 1400A ..