UNS C11000 copper
Specify electrolytic tough-pitch copper by product form, temper, conductivity and oxygen-sensitive processing requirements.
Tags: materials, copper, electrical-conductors, forming
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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, CDA conductivity reference
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
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, Kanthal conductive wire
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
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
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
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, PNA 211 conductivity note
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
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
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
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
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
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.