# UNS C11000 copper

Specify electrolytic tough-pitch copper by product form, temper, conductivity and oxygen-sensitive processing requirements.

Reviewed: 2026-11-01

Tags: materials, copper, electrical-conductors, forming

## Identify the material and purchase specification

Aurubis lists **≥58 MS/m (≥100% IACS)** for **PNA 211 Cu-ETP strip in the soft condition**. The CDA reference defines **100% IACS as 58 MS/m at 20°C**. Use temperature, temper and measured section for a conductor comparison. An installed current rating also requires joint resistance and heat dissipation. [Aurubis PNA 211 conductivity note](https://www.aurubis.com/es/dam/jcr%3A46190e64-c82a-4f86-b990-a0870243bbe8/PNA%20211_Cu-ETP_C11000-E.N-%5BRP%5D.pdf), [CDA conductivity reference](https://kupfer.de/wp-content/uploads/2019/11/Copper-for-Busbars.pdf)

**UNS C11000** denotes electrolytic tough-pitch copper, commonly associated with **Cu-ETP / CW004A** in European supplier literature. It is an oxygen-containing high-conductivity copper, rather than an oxygen-free grade. Aurubis' **PNA 211 strip** sheet lists copper **≥99.90%** and oxygen **≤0.04%**, with C11000, CW004A and JIS C110 as comparable designations. These are the named product's composition entries, not a promise that all cross-system requirements are identical. [Aurubis PNA 211, EN_2026_01](https://www.aurubis.com/es/dam/jcr%3A46190e64-c82a-4f86-b990-a0870243bbe8/PNA%20211_Cu-ETP_C11000-E.N-%5BRP%5D.pdf)

For example, Aurubis' US C11000 sheet identifies ASTM B152, B370 and ASME SB152 among applicable specifications, whereas Kanthal's C11000 conductive-wire sheet lists ASTM B1, B2, B3 and B250. Select the standard appropriate to the supplied product and function; do not apply a sheet-property row to wire because both carry C11000. [Aurubis US C11000 sheet](https://www.aurubis.com/es/dam/jcr%3Aec116d17-1541-419a-a897-ad31b4fa6c93/c11000-cu-etp-us.pdf), [Kanthal conductive wire](https://prodshop.kanthal.com/en/products/datasheets/material-datasheets/wire/conductive-wire/c11000-etp/)

## Temper and form control mechanical behavior

Cold-worked and soft conditions serve different purposes. Preserve the manufacturer's temper system rather than translating an R designation into an ASTM H temper by name alone. Compare strength, elongation, test basis, thickness and bend direction together.

The PNA 211 strip table illustrates the range:

| Supplier temper | Tensile strength | Yield strength | Elongation A50 |
| --- | --- | --- | --- |
| R220 | 220–260 MPa | ≤140 MPa | ≥33% |
| R290 | 290–360 MPa | ≥250 MPa | ≥4% |
| R360 | ≥360 MPa | ≥320 MPa | ≥2% |

These are supplier reference entries; confirm acceptance limits for the ordered size and condition. [Aurubis PNA 211](https://www.aurubis.com/es/dam/jcr%3A46190e64-c82a-4f86-b990-a0870243bbe8/PNA%20211_Cu-ETP_C11000-E.N-%5BRP%5D.pdf)

KME's C11000 sheet gives bend ratios only for **strip thickness ≤0.50 mm**. Its R360 90° values are **r/t = 1 good way and 2 bad way**. That thin-strip guidance is not a minimum bend-radius rule for thick busbar. Establish rolling direction, bend-axis convention, tooling and edge condition, and trial the actual stock when the bend is critical. [KME C11000 – Cu-ETP_2023](https://www.kme.com/fileadmin/DOWNLOADCENTER/COPPER%20DIVISON/4%20Industrial%20Rolled/3_Datasheets/01_2023_C11000_Cu-ETP_e.pdf)

The Copper Development Association's busbar guide explains that cold work increases strength while annealing softens copper. Consequently, the material state after a heating/joining cycle needs assessment: an incoming hard-temper certificate does not establish the finished heated region's strength. [Copper for Busbars, sections 1.2.2.2 and 1.2.3](https://kupfer.de/wp-content/uploads/2019/11/Copper-for-Busbars.pdf)

## Conductivity, resistance and a bounded example

**%IACS is a conductivity reference, not copper purity.** The CDA guide defines 100% IACS as **58 MS/m at 20°C**. Aurubis specifies its PNA 211 conductivity of **≥58 MS/m / ≥100% IACS for the soft condition only**. Keep condition and temperature with the value; do not treat room-temperature conductivity as a hot operating resistance. [CDA guide, section 1.2.2.1](https://kupfer.de/wp-content/uploads/2019/11/Copper-for-Busbars.pdf), [PNA 211 conductivity note](https://www.aurubis.com/es/dam/jcr%3A46190e64-c82a-4f86-b990-a0870243bbe8/PNA%20211_Cu-ETP_C11000-E.N-%5BRP%5D.pdf)

**Illustrative calculation, not a current rating:** assume a uniform 1 m conductor with cross-section 100 mm², conductivity exactly 58 MS/m at 20°C and DC current 100 A. Using R = L/(σA):

- A = 100 × 10⁻⁶ m²; R = 1/(58 × 10⁶ × 100 × 10⁻⁶) = **0.0001724 Ω**.
- Voltage drop IR = **0.01724 V**.
- Conductor loss I²R = **1.724 W**.

This excludes joints, temperature rise and AC effects. An installed current rating also needs cooling, enclosure, ambient temperature, support and connection limits. The CDA guide treats heat dissipation, skin/proximity effects and joint resistance separately; the calculation cannot replace that assessment. [CDA guide, sections 2 and 6](https://kupfer.de/wp-content/uploads/2019/11/Copper-for-Busbars.pdf)

## Oxygen-sensitive heating and joining

KME explains the relevant mechanism: during heating in a reducing atmosphere, hydrogen can penetrate copper and react with copper oxide to produce water vapor; the resulting pressure can cause embrittlement. Its processing table rates soft soldering/brazing favorably but resistance, gas-shielded arc and laser welding less favorably. Such ratings do not qualify a joint, filler, atmosphere or thermal cycle. [KME C11000 sheet](https://www.kme.com/fileadmin/DOWNLOADCENTER/COPPER%20DIVISON/4%20Industrial%20Rolled/3_Datasheets/01_2023_C11000_Cu-ETP_e.pdf)

Avoid reducing-atmosphere processing of ordinary oxygen-bearing ETP unless the specific material and process have been demonstrated suitable. Define furnace atmosphere, joining consumables, temperature/time and final inspection. If the design needs oxygen-free copper or a deoxidized joining grade, order that requirement explicitly rather than assuming all high-conductivity copper is equivalent.

An important bounded exception illustrates why supplier identity matters: **Aurubis PNA 213 wire**, marked **EN_2024_11**, is manufactured by the conform process from Cu-OFE and lists oxygen **≤0.002%**. Its description reports no hydrogen-embrittlement abnormalities, despite listing C11000/CW004A as comparable standards. The same sheet retains a general reducing-atmosphere warning on page 2. Resolve that inconsistency with the supplier before critical exposure; neither the introductory statement nor the comparable designation qualifies ordinary PNA 211 strip. [Aurubis PNA 213](https://www.aurubis.de/aurubis-com/dam/jcr%3A9e7f6dc8-3224-4db3-bc08-66453148ae45/PNA%20213_CuETP_C11000-EN-%5BBP%5D.pdf)

## Fabrication, exposure and release

KME rates C11000 cold forming excellent but machining less suitable, with a comparative machinability rating of 20. That rating is not a cutting-speed prescription. For machined conductors, qualify dimensions, burr removal, contact-surface condition and cleaning on the actual temper and tool setup. A substitute chosen for easier machining needs its own conductivity and joining review. [KME C11000 sheet](https://www.kme.com/fileadmin/DOWNLOADCENTER/COPPER%20DIVISON/4%20Industrial%20Rolled/3_Datasheets/01_2023_C11000_Cu-ETP_e.pdf)

Corrosion resistance is exposure-specific. Aurubis warns about ammonia, oxidizing acids and seawater, particularly at high flow rates. Record the actual fluid, concentration, temperature, flow and contacting materials; an architectural weathering application does not qualify a chemical-service component. [Aurubis PNA 211 exposure guidance](https://www.aurubis.com/es/dam/jcr%3A46190e64-c82a-4f86-b990-a0870243bbe8/PNA%20211_Cu-ETP_C11000-E.N-%5BRP%5D.pdf)

Release the component against its ordered grade/form/temper, dimensions, surface requirements and relevant electrical or mechanical tests. Retain material identity through plating, forming and heating, and distinguish incoming stock certification from demonstrated finished-assembly performance. Contact geometry and assembly instructions belong with an electrical connection, including its specified fastening procedure; raw copper conductivity alone does not establish connection reliability.

## Source versions and related reference

Primary sources were reviewed November 1, 2026. Printed identifiers are **Aurubis EN_2026_01**, **EN_2024_11**, **KME C11000 – Cu-ETP_2023**, and **Aurubis US 18 08 US**; the last code is preserved without interpreting it as a full revision date. Kanthal states **updated February 4, 2021**. The CDA guide is **revised May 2014**, rather than the date in its hosting URL. Supplier tables are selection references, with actual purchase acceptance governed by the agreed specification.

[Grades, conditions and material selection](../grades-tempers-and-conditions.md)