What is Busbar Current Carrying Capacity Calculation 5 Types of Busbar

What is Bus Bar?

Bus bar is a metallic strip or conductor shaped in square or rectangle or any…which is used in major electrical panel such as MCC (Motor Control Circuit), PCC (Power control circuit), MLDB (Main Lighting Distribution Board) etc.

Bus Bars are made up of copper or aluminium or iron or silver or galvanized iron etc. different types of bus bars are used for different types of applications.

For example, copper and aluminium used in electrical panel as conductor, iron bus bar used in traction conductor such as lifts, trolleys etc. galvanized iron is used as earthing bus bar. Gold and Silver bus bar is used in high conductivity applications.

Why Busbar are preferred for electrical installation?

  • Easy installations
  • Great flexibility
  • Easy plugin add-on (easy expandable)
  • High current carrying capacity as compared with cables
  • Easy manufacturing
  • Less cost.

Difference between AC bus bar and DC bus bar:

The bus bar which carries alternating current such bus bar is called AC busbar and the Busbar which carries direct current such a bus bar is called DC bus bar. But there is no difference at all. Many of the electrical engineer confuses about AC bus bar and DC busbar. In practically, Busbar means a conductor, which allows both Alternating current and Direct current that all. There is no difference or special manufacturing is required to carry alternating current and direct current. If a bus bar can allow 150 Amps means, we can send either AC 150 Amps or DC 150 Amps.

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Lets see the current carrying capacity of copper, aluminium, silver,

Copper Busbar current carrying capacity:

The copper has high conductivity and low resistivity. Copper is having high current carrying capacity.

I have worked in a panel manufacturing company for three years, the standard current carrying capacity of Copper busbar is 1.2 times of its area.

Which means, take a copper bus bar of 100 mm width and 10 mm thickness, the area of copper bus bar is 10 * 100 sqmm. The total current carrying capacity of the busbar is 1.2 * area => 1000 sqmm* 1.2 =1200 Amps.

Hence the total current carrying capacity of the copper 1200 Amps of 100mm width and 10 mm thickness.

Aluminium Busbar current carrying capacity:

The aluminium bus bar widely used and most popular than copper busbar. The aluminium bus bar is cheaper than copper busbar, but the resistivity of the aluminum busbar is high as compare with copper busbar.

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Also aluminum has the less current-carrying capacity as compared with copper. But performance/cost is high in aluminum bus bars. Take the same busbar of 100mm wide and 10 thick, the current carrying capacity of the aluminum busbar is 800 Amps. We should take a multiple factors as 0.8.

Iron busbar:

In very rare applications, the iron busbar used. Generally, these busbar used in trolleys, tractions, unloader etc. the I2R loss of the iron busbar is high as the resistance of the iron high. Iron bus bar is cheap as compared with aluminum and copper. These bus bars will get corrode easily. These are not suitable for high moisture are. Consider the same bus bar..

Galvanized steel busbar:

These galvanized bus bars are most popular in electrical earthing. You can see them in railway tracks. These bus bars are manufactured from iron and they will be galvanized. Hot dip galvanising protects the material such as steel and ferrous material from corrosion and various weather conditions by providing a tough metallic zinc envelope, which completely covers the steel surface and seals it from the corrosive action of its environment. Let see the current carrying capacity of the galvanized busbar.

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It is same as the iron busbar.

Cost comparison:

Copper > aluminium > galvanized iron > steel

Performance to cost ratio

Aluminium > copper > galvanized iron > steel

Also see:


    • Dear Sharma,

      As per IS standard, the Al bus bar should carry 0.7 to 0.8 A per cubic milli meter and Cupper should carry 1.2 Amps per cubic milli meter.


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