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Certifications: EN 10204 3.1 / 3.2 material test certificates, electrical conductivity (IACS) verification, and complete export documentation packages.
Copper C110
(ETP Copper)
A world-class technical reference for EPC contractors, electrical and mechanical engineers, procurement heads, and TPI inspection agencies specifying Copper C110 (Electrolytic Tough Pitch copper) bar, tube, sheet, and fabricated components — covering composition and metallurgy, the critical oxygen-content distinction from oxygen-free and phosphorus-deoxidised copper grades, mechanical and electrical properties by temper, hydrogen embrittlement risk in reducing atmospheres, and the QC and documentation discipline required for critical EPC and electrical project supply.
Composition &
Metallurgical Character
Copper C110 — Electrolytic Tough Pitch (ETP) copper, UNS C11000 — is the most widely produced and specified commercially pure copper grade globally, the default material for electrical conductor, busbar, and general engineering copper applications wherever maximum electrical and thermal conductivity at minimum cost is the governing specification driver.
1.1 — What Copper C110 (ETP Copper) Mean
C110 (also written C11000, its full five-digit UNS designation) is the Copper Development Association / UNS designation for Electrolytic Tough Pitch copper — the highest-volume commercially pure copper grade in global production. “Electrolytic” refers to the refining process (electrolytic refining of blister/anode copper to a minimum 99.90% purity); “tough pitch” is a historical metallurgical term referring to the deliberate, controlled presence of a small amount of dissolved oxygen (typically 0.02–0.04% by weight) in the copper, present as finely dispersed cuprous oxide (Cu₂O) particles within the copper matrix. This oxygen content is not a contaminant or defect — it is a deliberate, standard characteristic of ETP copper that arises from the fire-refining process historically used to control the “pitch” (a metallurgical term relating to the fracture/casting characteristics) of the copper, and remains a defining compositional feature of C110 to this day, distinguishing it from oxygen-free copper (C10100/C10200) and phosphorus-deoxidised copper (C12200) discussed in Section 1.3.
1.2 — Key Engineering Properties
Electrical Conductivity
C110 ETP copper is the reference standard against which electrical conductivity is measured — by definition, annealed ETP copper conductivity is 100% IACS (International Annealed Copper Standard), the baseline against which all other conductive metals and copper alloys are compared as a percentage. This exceptional electrical conductivity (second only to silver among practical engineering metals) is the primary reason C110 dominates electrical busbar, wire, and conductor applications.
Thermal Conductivity
Correspondingly high thermal conductivity (approximately 391 W/m·K at room temperature) makes C110 copper the standard material for heat exchanger tube, heat sink, and thermal management applications where efficient heat transfer is the governing design requirement.
Ductility and Formability
In the annealed (soft) temper, C110 copper offers excellent ductility, allowing extensive cold forming, drawing, and bending without cracking — a key characteristic supporting its use in wire drawing, tube forming, and gasket/washer applications requiring the material to conform to a mating surface under compressive load.
Corrosion Resistance
Good general atmospheric corrosion resistance through formation of a protective, adherent oxide/patina layer — copper corrodes very slowly in most atmospheric, freshwater, and many mild chemical environments, though it is attacked by ammonia-containing compounds (stress corrosion cracking risk in cold-worked tempers), strong oxidizing acids, and sulphide-containing environments (tarnishing).
1.3 — Critical Distinction: ETP (C110) vs. Oxygen-Free (C102) vs. Phosphorus-Deoxidised (C122) Copper
| Grade (UNS) | Type | Oxygen Content | Electrical Conductivity | Weldability / Reducing Atmosphere Service |
|---|---|---|---|---|
| C11000 (ETP) | Electrolytic Tough Pitch | 0.02–0.04% O (as Cu₂O) | 100% IACS (reference standard) | Not suitable for high-temperature reducing atmosphere or oxy-fuel welding — hydrogen embrittlement risk (Section 3.2) |
| C10200 (OF) | Oxygen-Free | < 0.001% O | 101% IACS (slightly higher than ETP) | Excellent — no hydrogen embrittlement risk; suitable for vacuum, hydrogen, and welding applications |
| C10100 (OFE) | Oxygen-Free Electronic | < 0.0005% O | 101% IACS | Excellent — highest purity, used for electronic/vacuum applications requiring maximum purity |
| C12200 (DHP) | Phosphorus-Deoxidised, High Residual P | Deoxidised — oxygen combined with phosphorus, not free | ~85% IACS (reduced by phosphorus content) | Excellent — the standard grade for copper tube requiring brazing/welding (e.g., refrigeration, plumbing tube) |
Product Forms
& Temper Classification
C110 copper is manufactured across bar, rod, tube, sheet, and wire product forms, each governed by a specific ASTM standard, and supplied in multiple temper conditions with mechanical properties controlled by the degree of cold work. Full detail on related materials is available across our standards reference library.
Submit form, temper, size, and quantity to sales@rrhydraulics.com for a certified offer.
2.1 — Governing Standards by Product Form
ASTM B152 — Copper Sheet, Strip, Plate, and Rolled Bar
Governs flat-rolled copper products including C110 sheet and plate — used for busbar, gasket blanks, electrical contact stock, and general fabrication sheet stock, defining chemical composition, temper designation, and dimensional tolerances.
ASTM B187 — Copper Bus Bar
The primary standard for copper busbar specifically for electrical power distribution applications — defines the rectangular bar dimensional tolerances, minimum electrical conductivity, and temper requirements specific to busbar’s high-current-carrying function.
ASTM B75 / B68 / B42 — Copper Tube
B75 governs seamless copper water tube; B68 governs seamless copper tube, bright annealed; B42 governs seamless copper pipe — the family of standards covering C110 copper tube in various finish and application-specific configurations for plumbing, refrigeration, and general fluid-carrying applications (though C122 DHP is more commonly specified where brazed joints are required, per Section 1.3).
ASTM B1 / B2 / B3 — Copper Wire
B1 (hard-drawn), B2 (medium hard-drawn), and B3 (soft/annealed) govern copper wire in the respective temper conditions — the standard specifications for C110 copper wire used in electrical conductor and general wire applications.
ASTM B133 — Copper Rod, Bar, and Shapes
Governs copper rod, bar, and various rolled/extruded shapes — the general specification for C110 bar stock used in machining, forging, and general fabrication applications beyond the specific busbar (B187) or sheet (B152) product forms.
ASTM B170 — Oxygen-Free Copper Reference
While governing C102/C101 oxygen-free copper rather than C110 directly, B170 is frequently referenced alongside C110 specifications to clarify the compositional distinction and guide correct grade selection between ETP and oxygen-free alternatives per the discussion in Section 1.3.
2.2 — Temper Classification and Mechanical Properties
| Temper | Designation | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Typical Application |
|---|---|---|---|---|---|
| O60 (Soft/Annealed) | Fully annealed — maximum ductility | 220–250 | 60–80 | 40–45 | Wire drawing, deep forming, gaskets/washers |
| H01 (Quarter-Hard) | Light cold work | 250–280 | 150–180 | 25–35 | Moderate forming with increased strength |
| H02 (Half-Hard) | Moderate cold work | 280–330 | 200–250 | 15–25 | Busbar, general engineering bar stock |
| H04 (Hard) | Significant cold work | 330–380 | 280–320 | 4–10 | Maximum strength applications, minimal forming required |
| H08 (Spring) | Heavy cold work | 380–420 | 340–380 | 1–4 | Spring contacts, applications requiring maximum hardness |
2.3 — Electrical Conductivity Verification
QC significance: Electrical conductivity measurement (per ASTM B193, using a four-point resistivity probe or eddy-current conductivity meter) is a standard, rapid QC check for C110 copper — a measured conductivity significantly below the expected 97–100% IACS range for the specified temper indicates possible contamination (particularly by common conductivity- degrading impurities such as phosphorus, iron, or silicon) or grade substitution, and should trigger further chemical composition verification.
Welding Limitations
& Fabrication Guidance
C110 ETP copper’s dissolved oxygen content — the same characteristic giving it its name — creates a specific and well-documented hydrogen embrittlement risk during high- temperature reducing-atmosphere processing that fundamentally limits its weldability and fabrication route compared to oxygen-free copper grades.
3.1 — The Mechanism: “Steam” or Hydrogen Embrittlement of Tough Pitch Copper
3.2 — Practical Implications for Fabrication and Service
Welding and Brazing Restrictions
C110 should not be oxy-fuel (oxy-acetylene) welded or brazed under reducing flame conditions, and is generally avoided for any welding process where the weld zone will be exposed to a hydrogen-bearing atmosphere — where copper components require welded or brazed joints, specify C102/C101 oxygen-free copper or C122 DHP copper (Section 1.3) instead, both of which lack the free dissolved oxygen that drives the embrittlement reaction.
Furnace Brazing and Annealing Atmosphere Control
Where C110 components must be furnace-annealed or furnace-brazed, the furnace atmosphere must be carefully controlled to avoid hydrogen or strongly reducing conditions — inert (nitrogen, argon) or oxidizing atmospheres are used instead, or the process temperature/duration is limited to avoid conditions conducive to the embrittlement reaction.
Service Temperature Considerations
C110 components in normal ambient-to-moderate-temperature service (well below the ~400°C threshold discussed above) are not at risk of hydrogen embrittlement from typical atmospheric or process fluid exposure — the risk is specifically associated with high-temperature fabrication processes and specific high-temperature reducing-atmosphere service environments, not general room-temperature or moderate-temperature use.
Mechanical Joining as the Preferred Alternative
For C110 components requiring a permanent joint where the embrittlement-prone fabrication route is undesirable, mechanical joining methods (compression fittings, crimping, bolted/riveted connections) or joining processes that do not involve the specific high-temperature reducing conditions that trigger embrittlement (e.g., soldering at lower temperature, or brazing under a properly controlled oxidizing/inert atmosphere) are the standard alternative fabrication approaches.
3.3 — Manufacturing Process
C110 copper is produced from electrolytically refined cathode copper, cast into shapes (billets, cakes, or wire bar) and then hot and/or cold worked into the finished product form — hot rolling or extrusion for bar, sheet, and busbar stock, followed by cold drawing/rolling to achieve the specified temper and final dimensions for wire, tube, and precision bar products. The tough-pitch fire-refining step historically controlled the residual oxygen content that defines the grade; modern electrolytic refining achieves the target 99.90%+ Cu purity with the characteristic 0.02–0.04% oxygen content controlled through the casting and refining process parameters.
Industry Applications
& Documentation
RR Hydraulic maintains full traceability from certified cathode copper heat to finished, tested, and packed C110 component shipment. Chemical composition, mechanical, and conductivity verification are standard on all project-grade supply.
4.1 — Inspection & QC Protocol
4.2 — EN 10204 / Documentation Requirements
| Certificate | Content | EPC Requirement | When Mandatory |
|---|---|---|---|
| 2.1 / 2.2 | Declaration / non-specific | Not acceptable for critical electrical or engineering supply | Never for busbar or critical conductor supply |
| 3.1 (EN 10204) | Heat-traceable chemical + mechanical + conductivity results | Mandatory — all EPC C110 supply | All busbar, conductor, and engineering component supply |
| 3.2 (EN 10204) | 3.1 + TPI countersign | Critical / owner-specified critical items | Safety-critical electrical infrastructure supply |
4.3 — Applications by Industry
Electrical Busbar and Power Distribution
C110 half-hard busbar (per ASTM B187) is the standard material for low-voltage and medium-voltage electrical power distribution busbar in switchgear, panel boards, and substation applications — the combination of 97–100% IACS conductivity and adequate mechanical strength/stiffness in the half-hard temper makes it the default busbar material across the electrical power industry worldwide.
Grounding and Earthing Systems
C110 copper rod, wire, and strip for electrical grounding and earthing systems — copper’s combination of high conductivity, good corrosion resistance in soil and atmospheric exposure, and established design basis in grounding system codes make it the standard earthing conductor material across electrical infrastructure projects.
Gaskets and Compression Sealing Washers
Annealed (soft temper) C110 copper washers and gaskets for compression sealing applications, particularly on high-pressure or high-temperature fittings where a soft, ductile, conformable sealing material is required — copper’s ductility in the annealed condition allows the gasket to deform and fill minor surface imperfections under bolt compression load, similar in application principle to the soft aluminium and stainless sealing washers discussed in RR Hydraulic’s other materials references.
4.4 — Export Packaging Specification
- Copper bar, sheet, and tube protected from surface tarnishing during transit with paper interleaving or light protective wrap, particularly for bright-finish or precision electrical contact stock
- Heat/lot number marked or tagged on each bundle/coil for traceability to the accompanying material test certificate
- Copper components segregated from steel and other ferrous materials during packing and storage to avoid surface contact marking or galvanic staining
- Documentation in a waterproof pocket: EN 10204 3.1/3.2 MTC, chemical composition report, mechanical properties report, electrical conductivity report, and packing list with form/temper/size breakdown per item
- ISPM-15 timber or export cartons for international shipment, with country of origin and HS tariff code documentation matched to the copper product form category
Submit your form, temper, size, and quantity to RR Hydraulic for a complete, certified commercial offer.