Indal dedicates significant attention to joints. Aluminium oxide (Al₂O₃) forms instantly and is insulating.
Required joint procedure:
Do NOT:
The Indal Handbook’s section on short-circuit performance is often cited in tender documents worldwide.
Unlike copper, aluminium’s lower conductivity exacerbates AC current crowding. The handbook provides a rule-of-thumb table for effective cross-section utilization at 50Hz:
| Bar Thickness (mm) | Utilisation Factor (AC/DC) |
| :--- | :--- |
| 6 mm | 97% |
| 10 mm | 92% |
| 15 mm | 84% |
| 20 mm | 73% |
Indal’s solution: For currents above 2500A, use multiple thin bars (e.g., two 10mm bars instead of one 20mm bar). This not only improves AC resistance but also increases surface area for cooling.