Cable Bus vs. Bus Duct

Comparison of the two technologies

Bus duct is defined in the NEC 368.2 as a grounded metal enclosure containing factory mounted, bare or insulated conductors, which are usually copper or aluminum bars, rods, or tubes

Types of Bus duct

  • Air insulated
  • Air insulated with segregated phase barriers
  • Gas insulated (sulfur hexafluoride)
  • Isolated phase
  • Forced Cooled
  • Enclosed oil cooled

Comparison of Bus Duct and Cable Bus

Bus Duct Superior Bus ™

System arrives as complete made to measure segments with conductors factory installed, only needing assembly.

  • Making small field adjustments very difficult if not impossible.

Arrives in pre-cut easy to assemble segments.

  • Can easily be modified and adjusted to fit on site.
  • Conductors installed after enclosure to ensure exact fit.

Busbar jointing can be simple, through the use of bolted connections.

  • Providing inadequate conductor contact area increasing joint resistance.
  • Require regular inspection and adjustment.
  • Drastically increase operating and maintenance costs.

Conductors are fully continuous throughout system.

  • Eliminating joint resistance, and potential weaknesses.
  • Simplifying installation.
  • Drastically reducing maintenance and operating costs.

Busbar jointing can be effective, through the use of copper welding, or clamped joints.

  • Largely increasing the cost of installation and/or materials.

Maintains free air rating.

  • Allowing cables to remain rated and use up to 40% less copper/aluminum
  • Greatly reduces conductor material costs.

Many system types available for specific application needs.

  • Increasing complexity of design and maintenance requirements
Only one type needed for almost all applications.