Indal (now part of the Hindalco Industries family) was a pioneer in the Indian aluminium industry. Recognizing that aluminium behaves differently than copper under electrical load, Indal produced a comprehensive design handbook. This document serves as a bridge between theoretical metallurgy and practical electrical engineering, ensuring that aluminium busbars are designed for safety, efficiency, and longevity.
The handbook suggests that for hot applications, a rectangular busbar with a higher aspect ratio (thin and wide) is superior to a square bar. Why? Because the surface area exposed to ambient air is maximized. For very high currents, the handbook recommends hollow sections or multi-laminate bars to increase the cooling perimeter without increasing weight.
The INDAL Handbook does not forbid aluminium busbars from running hot, but it imposes strict conditions: indal handbook for aluminium busbar hot
Final engineering rule from INDAL: A hot aluminium busbar is not a failed busbar—provided the heat is uniform, the joint pressure is maintained, and the thermal expansion is managed. A single hot joint is a pending arc flash.
If you need the actual numerical tables from the original INDAL handbook (current ratings vs. cross-section vs. temperature), let me know and I can reconstruct those based on E91E alloy datasheets. Indal (now part of the Hindalco Industries family)
For hot/high-load applications, the handbook typically specifies:
Published by: Power Engineering Review / INDAL Technical Series The INDAL Handbook does not forbid aluminium busbars
Scenario: 2500A aluminium busbar in a 50°C ambient chemical plant. Observation: Joint temperatures reached 145°C after 2 years. Root cause per INDAL:
Remediation: