what is busbar ? why its used ? what is the advantage (benefit) of using it ?

what is busbar ? why its used ?

what is the advantage (benefit) of using it ?

what's the disadvantage of using it in a distribution ?

what should be the size of busbar(s) if the load is 150 Amps ?

How many should be the strips of the busbars ?

Is it used to bear the load or to divide the load ? Or to bear the maximum load on itself & not on the cable only ?

thanks

If you have a factory with multiple high power machines you might have a 300 A incoming breaker (three phase + neutral), feeding 4 busbars along the back of the cabinet. There would also be a earth busbar. So machine #1, would be fed by a 50A isolator, which would have three phases running through it, each being connected to the busbars with a piece of wire. The outputs from the isolator would go through fuses, then off to the machine with the machines earth wire connected to the earth busbar. This arrangement would be in place for each machine. If a circuit was only single phase, then a selected phase + neutral would be used, again this would be duplicated for all single phase circuits using a different phase to balance the load as required.
The bus bar is a physically convenient method of spreading the output terminals of the incoming breaker, to perhaps 20 different circuits.
Frank