| Parameter | Limit (INDAL/E91E Alloy) | Consequence of Exceedance | | :--- | :--- | :--- | | | 105°C (Class B insulation rating) | Annealing (loss of tensile strength) | | Short Circuit Temp (1 sec) | 250°C | Permanent deformation, joint loosening | | Junction/Contact Temp | 90°C (with bolted joints) | Creep relaxation → arc flash risk | | Ambient Correction | Derate 1.5% per °C above 35°C | Premature aging of insulation |
(Coating) : Adjusts ratings for painted, sleeved, or bare busbars. indal handbook for aluminium busbar hot
Power systems occasionally run at 120-150% rated load. The INDAL handbook allows this for aluminium, but with strict limits: | Parameter | Limit (INDAL/E91E Alloy) | Consequence
. This involves starting with a "Basic Rating" and applying specific derating factors ( to account for real-world operating conditions: Indal Al Busbar | PDF - Scribd This involves starting with a "Basic Rating" and
(Enclosure Factor): Factors in the size and ventilation of the enclosure . 3. Manufacturing via Hot Extrusion
While often considered a "high frequency" issue, the INDAL handbook notes that at high currents (4000A+), the becomes a thermal problem. As the bar heats, the resistivity rises, pushing current toward the surface.