Busbar Conductor

Cuponal

Cuponal is an established bi-metallic conductor developed to provide an economic alternative to solid copper in busbar applications.
Cuponal consists of a solid core of electrical grade aluminium with an outer layer of copper molecularly bonded to the aluminium core during manufacture.
Cuponal has been successfully evaluated and used by many of the world's leading electrical equipment manufacturers.  Applications include L.V. distribution, switchboards, motor control centres, panel boards, busbar chambers, overhead busbar trunking systems, H.V. distribution, vacuum switchgear and generator sets.  Cuponal is also used in transformer and rectifier applications, motor windings, fuse gear and crane rail supply systems.

Advantages
Cuponal combines the advantages of two established conductive metals in one carefully engineered conductor offering economic and weight saving advantages over solid copper without any detrimental effect to reliability.
Cuponal in many applications can offer the same performance size for size as solid copper busbars without the expense or weight of solid copper.

Costs
In many applications considerable savings can be achieved in both the material and labour costs when compared with solid copper conductors.
Dependent upon application, cost savings of at least 15% and in some instances as high as 30% can be achieved when compared with solid copper components.

Approvals and Standards
Cuponal complies with BS159-1957 and conforms to DIN43670 Part 2.
The aluminium core is electrical grade to DIN40501, Part 3 and the copper cladding to BS1036.
Additionally Cuponal has been approved for use by the following authorities: Germanischer Lloyd, Net Norske Veritas, ABS, Bureau Veritas Lloyds, SABS, ULA, British Telecom, British Rail, British Steel, British Aerospace, CEGB.

Working with Cuponal
Cuponal is as easy to work with as solid copper busbars.  Requiring only minor modifications to bending techniques, while cutting, punching and joining are easily accomplished.

Support Systems
Cuponal is compatible with most commercially available busbar support systems.

Bending
Cuponal busbars may be readily bent, normal to the plane or on edge, by the methods outlined below.  Cuponal has less spring back than copper, and as a result a bend is easier to achieve.  However, a larger radius is required than with copper to allow for the flow characteristics of the copper aluminium mating face.  Cuponal busbar should not be bent around a knife edge.  The recommended radii for bending standard rectangular sizes of Cuponal busbar are detailed in the Table 3.  Forming pressure should be applied gradually and not by impact.  Drilling and punching should be performed after bending is complete.

Bending Method 1
This involves pressing a forming tool against the bar, the reverse side of which is resting against two smooth supports.  The surface of both the forming tool and the supports must be smooth.  It is important that the two supports are set sufficiently far apart to permit the bar to move and bend freely as pressure is applied to the forming tool.  For angles of bend greater than ninety degrees, it may be necessary to set the supports closer together to complete the final stage of the bend.

Bending Method 2
This involves holding the busbar firmly against a forming tool and applying pressure to the revers side of the bar by means of a rolling or sliding follower.  When using this method with the busbar gripped in a vice or clamp, it is important that the point of grip is sufficiently far from the bend to allow for elongation and material flow at the bend.  A distance of about four times the thickness (or width for an edge bend) from the clamp to the start for the bend has proved adequate.

Bolted Joints
Contact surfaces should be flat, clean and uniformly roughened.  Perfectly flat joint faces are not necessary since very good results will be obtained merely by ensuring that the joint is clean and tight.  A slight improvement may be gained by preventing reoxidation of the surfaces after cleaning by coating the surfaces with petroleum jelly.

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Last modified: June 29, 2001