CUPAL standards and the standards of its application area

When it comes to CUPAL copper-aluminium bimetal composite, it is important to draw a clear distinction between the standards of the material itself and the standards of its application area. This article presents these two categories cleanly separated.

The material standards of CUPAL

The two constituents of CUPAL — the aluminium core and the copper cladding — are formally classified by the following material standards:

Aluminium component

Copper component

Quality assurance on the supplier side

We source the CUPAL base material from Germany (WMH Westdeutscher Metall-Handel GmbH, Essen). The supply chain operates under an ISO 9001:2015 quality management system, which ensures consistent, traceable material quality on every shipment.

These three standards — DIN 17007, DIN 1787 and ISO 9001:2015 — directly describe the CUPAL material itself and the process by which it is supplied.

The standards of the application area

These standards do not apply to the CUPAL material; they apply to the equipment and joints in which CUPAL transition elements (washers, sheets, strips) are typically used. CUPAL is a solution that fits into these contexts, but it is not a product holding a "certificate" against them.

DIN 43671 — copper and aluminium busbars

DIN 43671 governs the dimensions, current-carrying capacity and design principles of copper and aluminium busbars used in switchgear. When connecting busbars made of dissimilar metals, a CUPAL transition element can be the appropriate solution in the spirit of this standard.

IEC 61439 — low-voltage switchgear and controlgear assemblies

The IEC 61439 series sets out the design, manufacturing and verification requirements for low-voltage distribution boards and switchgear cabinets, including the assessment of contact resistance and temperature rise. In assemblies built to IEC 61439, CUPAL transition elements can be used to form Cu/Al joints.

IEC 61238 — compression and mechanical connectors

IEC 61238 lays down the requirements for compression and mechanical connectors used on power cables (mechanical, electrical and thermal tests). At connections between dissimilar metals, a CUPAL washer or transition element helps create a contact zone that supports meeting these requirements.

IEC 62305 — lightning protection

The IEC 62305 series defines the requirements for the lightning protection systems of buildings and structures. At joints between dissimilar metals (e.g. a copper gutter and an aluminium down-conductor), a CUPAL strip or transition element can provide corrosion protection for the joint.

Material and environmental compliance

The material contains no substances restricted under RoHS/REACH. An SVHC-free declaration can be requested per shipment from our supplier, tied to a specific project or production lot.

Why the distinction matters

In practice, a design engineer asks two questions:

1. "What material is CUPAL made of?" — DIN 17007 / DIN 1787 / the Werkstoff numbers give the precise answer.
2. "Can CUPAL be used for the Cu/Al transition in my equipment, which I design to IEC 61439 / DIN 43671 / IEC 62305?" — Yes; CUPAL is a transition material developed for exactly this purpose and proven over decades.

What must be made clear, however, is that the conformity of the equipment (e.g. the certification of a switchgear cabinet manufactured to IEC 61439) is always demonstrated by the equipment manufacturer — CUPAL participates in this as a component.

Summary

• CUPAL material standards: DIN 17007 (Al 3.0255), DIN 1787 (Cu 2.0065), supplier ISO 9001:2015.
• Application-area standards: DIN 43671, IEC 61439, IEC 61238, IEC 62305 — it is the equipment that conforms to these, with CUPAL featuring as a compatible transition material in that context.
• RoHS/REACH: an SVHC-free declaration can be requested per shipment.

For questions about interpreting standards or project-specific material classification, request expert advice.