Knowledge Base
Technical guides, application tips and answers about CUPAL — in plain English
What CUPAL bimetal is, and when you need it
CUPAL is a cold-roll-bonded, diffusion-welded copper-aluminium composite: an aluminium core with a copper cladding. You need it wherever copper and aluminium conductors meet in a bolted joint — busbar transitions, switchgear cabinets, cable-lug connections. Direct Cu–Al contact starts galvanic corrosion, contact resistance rises and the joint runs hot. Interposing a CUPAL transition washer, sheet or strip means each side only ever touches its own metal. The articles below cover the material itself, size selection, installation and the relevant DIN and IEC standards.
Laser cutting or punching? Custom CUPAL parts from a drawing — which process pays off when
A custom copper-aluminium part can be cut from CUPAL sheet in three ways: on a shear, by laser or with a punching tool. What decides between them, what is different with a bimetal, and what to put in your quote request to get an accurate price first time.
Transition washer: toothed or bimetallic? How to tell which one your drawing means
Two physically different parts are sold as a transition washer — a toothed copper-alloy washer and a roll-bonded copper–aluminium bimetal disc. How to tell them apart, which suits which joint, and the 11 bimetal sizes from M6 to M20.
Connecting Copper to Aluminium: Which Part for Which Joint
Copper meets aluminium in five different joints, and each one takes a different part — including one where the answer is not us. Which lug, splice, washer or cut plate fits, in what size, and which way round it goes.
CUPAL part number cross-reference: which size matches your code?
Distributor and manufacturer designations for CUPAL washers, sheet and strip — 880111, 880109, ICALCU10CS, Cupal M 10 Al-Cu, VCUP2, 1053 — mapped to the sizes we stock, with dimensions and our SKU.
Connecting a copper cable to an aluminium mast without galvanic corrosion
Bolting a copper earth or bonding cable straight to an aluminium mast starts galvanic corrosion within a season. What actually fails, why a stainless washer only delays it, and what to put in the joint instead.
CUPAL vs. Copper–Aluminium Transition Methods: Which One Lasts?
CUPAL bimetal compared against the real copper–aluminium jointing alternatives — antioxidant paste, CCA conductor, bimetal cable lug and the bare bolted joint — on permanence, galvanic-corrosion protection and IEC 61238 / IEC 61439.
EN 10204 2.2 Certificate Meaning — Type 2.2 vs 3.1 Explained
EN 10204 type 2.2 is a generic test report; type 3.1 is a lot-specific inspection certificate. What each type means, when you need which, and how to request one for a CUPAL order.
CUPAL ISO 9001:2015 compliance (WMH supplier chain)
The CUPAL base material is supplied by our German supplier WMH Westdeutscher Metall-Handel GmbH under an ISO 9001:2015 certified quality management system. What does this mean in practice for audits and public procurement?
CUPAL RoHS / REACH compliance and SVHC declaration
CUPAL copper-aluminium bimetal contains no substances restricted under RoHS / REACH. An SVHC-free declaration can be requested per shipment or tied to a specific project.
CUPAL Installation and Processing Guide
How do you process CUPAL? A guide to cutting, bending, soldering, electroplating and the heat-treatment limits.
CUPAL washer size guide: which size should I choose?
How to select the right CUPAL washer size, with a table of every available size from M6 to M20.
CUPAL technical datasheet — full specification
Full technical datasheet of the CUPAL copper-aluminum bimetal composite material: physical, mechanical and chemical properties.
CUPAL standards and the standards of its application area
The actual material standards of CUPAL bimetal (DIN 17007, DIN 1787, ISO 9001) and the standards of its application area (DIN 43671, IEC 61439, IEC 61238, IEC 62305).
Can Copper & Aluminium Touch? Galvanic Corrosion Explained
Yes, copper and aluminium can touch — but their ~2 V potential difference drives galvanic corrosion. A CUPAL bimetal transition layer stops it (IEC 61238).
CUPAL vs Pure Copper vs Aluminium — A Comparison
A detailed comparison of CUPAL, pure copper and aluminium: weight, conductivity, cost and corrosion resistance.
What is CUPAL?
CUPAL is a cold-roll-bonded, diffusion-welded copper-aluminum bimetal composite. Learn its composition, manufacturing process and properties.
Have a question?
Got a question about a specific joint? Send us the size and thickness — we reply with a quote within one business day.