C101 / CW004A / ETP Copper

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Electrolytic Tough Pitch Copper (ETP)  C101 / CW004A is a commercially pure high conductivity grade of copper refined by electrolytic deposition which is then melted and oxidised to the “tough pitch” condition with a controlled low oxygen content. This is the most widely used of all the coppers because of its combination of electrical and thermal conductivity, corrosion resistance, workability and aesthetic beauty.

C101 / CW004A is the normal grade for general electrical use as busbar, motor and transformer components, windings and many other current carrying applications. It is also very popular with architects for applications where the corrosion resistance is required for building applications. Over time the C101 will also develop the weathered copper, green patina, appearance that offers additional corrosion resistance and a desirable look.  

The use of this alloy in elevated temperature environments can be limited due to oxygen being present in the form of Cu2O. This can cause the alloy to be susceptible to hydrogen embrittlement in reducing gasses or when welding or brazing using an oxy-fuel gas flame.

Chemical Composition


99.90 min


0.005 – 0.040

Total Imps

0.03% max (excl. O2 & Ag)

Related Specifications




C11000 ETP


DIN 2.0060

Key Features

  • Very High Electrical Conductivity 
  • Excellent formability
  • Very Good Thermal Conductivity
  • Excellent Joining Characteristics

 Typical Physical Properties

Melting Point  



8.92 g/cm³

Specific heat

385 J/Kg °K

Thermal conductivity

393 W/m°K

Thermal expansion coefficient  (20-200°C)

17.3 x 10-6 Per °C

Electrical conductivity

100 % IACS

Electrical Resistivity  

0.0172 x10-6 microhm /m 

Modulus of elasticity

118000 N/mm²

Fabrication Properties

Hot Working Temperature Range


Hot Formability


Cold Formability


Cold reduction between anneals

90% max

Machinability rating

(free cutting brass = 100)            


Annealing Temp. Range


Stress Relieving Temp. Range


Joining Methods





Oxy-acetylene welding

Less Suitable

Gas-shielded arc welding


Resistance welding:   spot and seam

Not Recomended


Typical Uses:

The C101 / CW004A is mostly utilised for general electrical busbar, motor and transformer components, windings, electrical conductors, contacts, terminals and many other current carrying applications. Other uses include architectural metalwork, gutters, flashing, roofing, automotive and industrial radiators, together with chemical process equipment, vats, kettles and pans.

This technical information is given by Holme Dodsworth Metals without charge and the user shall employ such information at their own discretion and risk. For more detailed technical advice on temper selection, fabrication, joining, machining, physical and mechanical data please contact us as space does not permit the listing of every feature of the material.

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Holme Dodsworth Metals Limited.
59/69 Heaton Park Road.
Newcastle Upon Tyne NE6 1SQ
Registered in England. Company No. 00842702