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Material generally used for bus bar is
Copper
Aluminium
Steel
Tungsten
Aluminium
Aluminium is the most widely used material for modern electrical bus bars due to its excellent balance of cost-effectiveness, weight, and conductivity. While copper has higher electrical conductivity, aluminium's significantly lower cost and weight-to-performance ratio make it the standard for high-current sub-station and industrial distribution applications.
Aluminium is the most widely used material for modern electrical bus bars due to its excellent balance of cost-effectiveness, weight, and conductivity. While copper has higher electrical conductivity, aluminium's significantly lower cost and weight-to-performance ratio make it the standard for high-current sub-station and industrial distribution applications.
R=╧БALтАЛ тАФ Resistance formula relating material resistivity ╧Б to bus bar dimensions
I=J├ЧA тАФ Current capacity based on current density J and cross-sectional area A
A bus bar acts as a low-impedance junction where multiple power circuits are connected. The selection of material depends on the resistivity (╧Б), temperature coefficient of resistance (╬▒), and mechanical properties. Aluminium provides roughly 61% of the conductivity of copper but is about 30% of its weight, reducing structural support requirements in large substations.
Aluminium is preferred for its low density (2.70 g/cm┬│) compared to copper (8.96 g/cm┬│).
Bus bars are sized to maintain current density within limits to prevent overheating.
Corrosion resistance is enhanced by the natural oxide layer on aluminium surfaces.
Copper is still used in space-constrained environments due to higher conductivity.
Significantly cheaper than copper
Lightweight, reducing structural costs
Easily extruded into desired shapes
Good resistance to atmospheric corrosion
Lower conductivity than copper (requires larger cross-section)
Forms insulating oxide layer requiring specialized contact joint preparation
Higher thermal expansion coefficient
Indoor and outdoor electrical substations
Industrial power distribution boards
Large-scale switchgear assemblies
| Feature | Copper | Aluminium |
|---|---|---|
Conductivity (% of IACS) | 97-100% | 60-61% |
Density (g/cm┬│) | 8.96 | 2.70 |
The International Annealed Copper Standard (IACS) defines pure annealed copper as 100% conductivity.
Option A (Copper) is technically superior in electrical performance but often economically unfeasible for large-scale utility bus systems.
Tungsten (Option D) has a high melting point but is rarely used for bus bars due to high resistivity and cost.
B is correct тАФ Aluminium is the most economically viable and widely adopted material for large-scale electrical bus bar installations.
Always remember that in electrical design, economic constraints often dictate material choice over pure physical performance (conductivity) unless space is severely limited.