Aluminum tubular busbars are typically supplied in maximum lengths of 12 meters locally, with welded sections allowing total lengths up to about 140 meters.

Typical Lengths and Manufacturing Limits

For aluminum tubular busbars used in high-voltage outdoor substations, local manufacturing in Southern Africa can produce tubes with diameters up to 160 mm and wall thicknesses of 8 mm, with a maximum length of 12 meters per section. Larger diameters or longer lengths are usually supplied by recognized foreign manufacturers. To achieve longer runs, tubular busbars can be welded together, allowing a total continuous length of approximately 140 meters .

Material and Standards

Aluminum busbars are commonly manufactured according to EN 755-2, which specifies aluminum alloy properties. The choice of alloy affects both mechanical strength and electrical conductivity:

• Alloy 6101B T6: Higher mechanical strength, lower conductivity
• Alloy 6101B T7: Higher conductivity, lower mechanical strength Copper tubular busbars are also used, particularly for extensions to existing copper systems, and must match the existing type and fittings .

Design Considerations

The length of a busbar section is influenced by:

• Thermal loads: Ensuring the busbar can carry the rated current without excessive temperature rise
• Mechanical loads: Including short-circuit forces, wind loading, and support span between insulators
• Support spacing: Maximum span between busbar supports is critical to prevent sagging or mechanical failure

Summary

• Local aluminum tubular busbar length: up to 12 meters per section
• Total welded length: up to ~140 meters
• Material standards: EN 755-2 for aluminum, ENA TS 41-11 for fittings
• Design factors: Current rating, short-circuit withstand, mechanical support, and thermal limits These specifications ensure safe, reliable, and efficient operation of tubular busbars in substations and high-current applications.