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A Guide to Copper Wires

Copper wires conduct electrical currents that power our homes and electrical appliances we use every day. Copper wire is the preferred conductor for many electrical applications because of the high conductivity of copper, which contributes to its optimal performance. Suitable for a wide range of applications due to its versatility, copper requires less insulation and can be stretched more effectively than other metals. Though copper is an excellent conductor of electricity, there are several different types of copper conductors to choose from, and it is important to understand the variances when selecting wire for your application.

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A Guide to Copper Wires

Types of Copper Conductors

Copper conductors are available in many different varieties, each with its own benefits. The types include:

  • Copper Bare: As indicated by the name, bare copper does not have any coating. Bare copper wire has excellent conductive properties, high strength, good ductility, malleability, and creep resistance, making bare copper conductors ideal for applications in electrical transmission, jumpers, grounding electrical systems, electrical hookups, and electrical appliances.
  • Copper Tin Plated: This is uninsulated copper wire coated with a thin layer of tin to protect against oxidation. A tin-plated copper wire has exceptional conductivity, weldability, and resistance to corrosive environments and is suitable for water treatment, desalination, power generation, and chemical processing applications.
  • Copper Wire Plated with Nickel or Silver: This copper alloy conductor is often used in aerospace, defense, petrochemical, nuclear, and medical applications.
  • Oxygen-Free Copper Wire: can be bare or plated. This is a top-grade type of copper wire that’s been refined in an electrically charged solution of copper sulfate and sulfuric acid, causing the copper to have an exceptionally low oxygen level (0.001%). Oxygen-free copper wire offers high thermal and electrical conductivity, great corrosion resistance and solderability, and higher temperature resistance, recrystallization, and workability making it suitable for applications that demand high durability and accuracy.
  • Copper Clad Steel (CCS): This type of wire combines the high tensile strength of steel as its core and the conductive properties of copper as its outer layer. Common applications of copper-clad steel wire include temperature measuring instruments, medical products, motors, intelligent pressure, hardware, magnetic assemblies, and power supplies.
  • Copper Clad Aluminum (CCA): With an aluminum core and an external layer of copper, copper-clad aluminum is a more affordable alternative to pure copper wire. CCA possesses increased strength compared to copper and enhanced conductivity compared to aluminum.
  • Copper Alloy: Conductor made of copper alloy might include different chemical elements, which define the properties of the final product – copper alloy wire. Here are a few examples of copper alloys: Zirconium, Beryllium, Chromium, Cadmium, Brass and Bronze. Application and requirements for strength, solderability, durability, and insulation define which copper alloy conductor to utilize.

Copper Wire Applications

Copper wires are used in various applications:

  • Electrical wiring: Copper wire is most commonly used in residential and commercial buildings to generate power. Approximately half of all mined copper is used to produce electrical wiring.
  • Industrial machinery: Copper wires are used in industrial applications such as factory automation, robotics, mining operations, railway infrastructure, residential and commercial construction, industrial heating, and watercraft applications.
  • Power generation: Copper wires are used in power generation systems as electrical conductors.
  • Telecommunications: While fiber optic is taking over in the telecommunications industry, copper wires are still being used for High Digital Subscriber Line (HDSL) and Asymmetrical Digital Subscriber Lines (ADSL).
  • Automobile industry: Copper wire applications for the automobile industry include aftermarket electrical components, battery cables and charging stations, shielding products, busbars for EV battery interconnects, and airbags.
  • Aerospace: Valued for its thermal and electrical conductivity, copper wire is commonly used in aerospace applications such as airframe wiring, in-flight entertainment, cabin management systems, and more.

Benefits of Copper Wire

  • Electrical and thermal conductivity: The high electrical and thermal conductivity of copper makes it stand out from other metals. This makes copper wiring the go-to option for applications such as transformers, switch gears, and many other electrical applications.
  • Ductility and malleability: Copper wires are highly ductile and malleable and can be formed and stretched easily without breaking or affecting their electrical properties.
  • Good tensile strength: Copper wiring has a high tensile strength which prevents breakage, stretching, and other physical damage.
  • Creep resistance: Creep is the deformation of metal conductors that occurs when they expand and contract under cyclic loads. Copper has higher creep resistance compared to other metals like aluminum.
  • Corrosion resistance: Copper wires generally have good corrosion resistance properties and keep good performance when affected by moisture, humidity, industrial pollution, and other environments.

Copper Wire Products at International Wire

Copper wiring is the most versatile wiring product with applications across industries. It offers excellent electrical and thermal conductivity, malleability and ductility, tensile strength, creep and corrosion resistance, as well as impressive alloy compatibility. At International Wire, we provide a wide range of copper wire products which include single-end wire and copper wire on bobbins, metal and textile braided products, stranded conductors, and flat wire. Contact us today to learn more, or request a quote.

Types of Copper Alloys

Unlike pure copper, copper alloys are complex formulations of metal with a copper base and alloy elements such as nickel, aluminum, silicon, tin, and zinc in varying concentrations that give the alloy desired properties. Learn more about popular copper alloys and their common applications.

ETP and OF CopperBare Copper Wire

Two popular alloys of copper are electrolytic tough pitch (ETP) copper and oxygen-free (OF) copper.

ETP Copper (C110)

For ETP copper properties, this alloy is extremely versatile and is the most commonly used copper alloy. It offers 100% IACS minimum conductivity, making it popular for electrical applications and those necessitating low resistance levels. 

OF Copper (C101)

OF copper is a 99.99% pure copper alloy with 0.0005% oxygen content. This alloy has 101% IACS conductivity rating, it is resistant to oxidation, and less vulnerable to hydrogen embrittlement.


Both ETP and OF coppers are malleable, making them easy to work with and form during manufacturing. These alloys offer high levels of thermal and electrical conductivity and low chemical reactivity. They also have resistance properties for oxidation, corrosion, microbes, and bacterial contamination. 


Some of their most common applications include:

  •     Aerospace parts
  •     Construction
  •     Electronics
  •     Elements in heat exchangers
  •     Medical equipment
  •     Power transmission lines and components

Cadmium Copper (C162)

Cadmium copper is a high-performance alloy made from 98 – 99 % % copper, 0.1 – 1.5% cadmium and sometimes minor amounts of other materials. The cadmium imbues the metal with more strength and makes it responsive to some heat treatments.


Cadmium copper offers an extended flex life and good tensile strength characteristics, making it a more pliable option for industrial and scientific applications. The alloy also has excellent thermal stability and a high degree of electrical conductivity.


Some of the most popular applications of cadmium copper include:

  •     Electrical components (circuit breaker switches, connectors, spring contacts, electrical conductors)
  •     Trolley wire
  •     Geophysical exploration equipment
  •     High strength transmissions lines

Tensile-Flex High-Performance Copper Alloy

This alloy is recognized as a high-performance conductor alloy that can perform specialized functions while meeting or exceeding the requirements of industrial regulations. Tensile-flex high-performance copper alloy complies with the following industrial standards:

  •     ASTM B624
  •     MIL-W-29606
  •     NEMA WC67
  •     SAE AS22759


This alloy has high tensile strength and maintains this key characteristic even at elevated temperatures of 700° F and higher. The material also has high thermal stability and excellent conductivity characteristics and can resist annealing at high temperatures.


Because this alloy retains its positive characteristics at high temperatures, it’s an excellent choice for:

  •     Aerospace 
  •     Medical applications
  •     Geophysical applications

80EF: Environmentally Friendly Copper Alloy

80EF copper is a Restriction of Hazardous Substances (RoHS)-compliant alternative to cadmium copper. This alloy doesn’t have cadmium and other heavy metals like lead or mercury in its composition.


Despite not having cadmium, 80EF still has extremely favorable characteristics, such as good flex life and tensile strength, and it operates similarly to cadmium copper. It’s also highly conductive and offers good thermal stability. 


This alloy is ideal for applications that must comply with RoHS regulations and requirements. Additional applications include:

  •     Commercial aerospace applications
  •     Geophysical exploration components
  •     Medical equipment

35EF: Environmentally Friendly Copper Alloy

35EF copper alloy is free of heavy metals like cadmium, lead, or mercury. Alloy 35EF copper also complies with several specialized industry standards, including:

  •     ASTM B624
  •     MIL-W-29606
  •     NEMA WC67
  •     SAE AS22759


35EF is thermally stable and offers excellent conductivity. It also has a high tensile strength that makes it ideal for a variety of applications.


This alloy is a popular choice for any RoHS application due to its directive compliance.

CS-95: Ultra-High Strength Copper Alloy

This alloy has a composition that offers increased strength for use in extreme environments. It allows manufacturers to decrease the size and weight of components without sacrificing strength or integrity.


Ultra-high-strength copper alloy has excellent strength- and conductivity-to-weight ratios as well as a high degree of tensile strength. This durable alloy has excellent flex life in mechanical applications, and it’s another RoHS-compliant alloy.


Components fabricated from ultra-high strength copper alloy CS-95 are used in the following applications:

  •     Aerospace and aeronautic cabling systems
  •     Miniature electronics
  •   Medical diagnostic equipment
  •   Miniature Invasive Medical Sensors and Probes

BronzeBronze Wire on Bobbin

Bronze alloys are composed primarily of copper and about 12-12.5% tin, as well as other metals, such as aluminum, manganese, nickel, phosphorus, or silicon.


Regarding bronze’s properties, the alloy is well regarded for its strength, resistance to corrosion and conductivity.


Some of the most common applications of bronze include:

  •     Automotive parts
  •     Electronic and electrical components, including contacts and relays
  •     Marine components

Copper Alloy Wires at International Wire

As a leading U.S. manufacturer of copper alloy wire products, International Wire Group utilizes high-quality metals to meet clients’ unique specifications. Contact us today to learn more about our selection of copper alloys or our in-house cable services.

Tinned Copper vs. Bare Copper Wire

Electrical wires and cables made from copper are designed to conduct electric currents. Depending on the application, you may require either bare copper or tinned copper conductors. International Wire Group offers reliable bare and tinned wires and cables that provide top-notch performance in various industries and applications. Learn more about the features, benefits, and applications of tinned copper and bare copper wires.

What Is Tinned Copper Wire?

Tinned copper wire is an uninsulated wire that is coated by a layer of tin. Why do you need tin-plated copper wire? Recently manufactured, fresh bare copper conductor works very well, but bare copper wire is prone to oxidation over time much more than its tinner counterpart. Oxidation of bare wire leads to its degradation and failure in electrical performance. The tin coating protects wire from oxidation in humid and rainy conditions, high heat environments, and in some soil types. Generally, tinned copper is used in environments with long-term exposure to excess moisture to prolong the lifespan of copper conductors.Solid Tinned Copper Wire

Benefits of Tinned Copper Wire

Bare copper and tinned copper wires are equally conductive, but the latter provides robust protection against corrosion and oxidation. Here are some other benefits of tinned copper wires:

  • Corrosion resistance, especially in wet or saltwater environments
  • Extended cable life
  • Easy solderability

Tinned Copper Wire Applications

Tinned copper wires are preferred for humid and high-temperature environments. The following are some specific applications:

  • Electronic components
  • Circuit boards
  • Test lead wire
  • Wastewater treatment facilities
  • Subway systems
  • Utility projects
  • Jewelry making

What Is Bare Copper Wire?

As the name suggests, bare copper wire is a copper wire with no coating. Bare copper possesses unmatched conductive properties and can be made in hard, medium-hard, or soft annealed tempers. Bare wire is also known as grounding wire. Bare conductors are available in stranded, braided, or solid (single-end) constructions, depending on the requirements of the application.Solid Bare Copper Wire

Benefits of Bare Copper Wire

Copper is one of the best conductors of electricity, second only to silver. These are several other benefits of bare copper wires:

  • High thermal conductivity
  • Good ductility and malleability
  • High strength
  • Creep resistance
  • High melting point
  • Long-term durability
  • Good solderability
  • Resistance to damage while handling a large amount of electricity

Bare Copper Wire Applications

Bare copper wire is best for use in dry environments, including these applications:

  • Electrical transmission
  • Grounding electrical systems
  • Electrical hookups
  • Jumpers
  • Electrical appliances

Copper Wire Products at International Wire Group

When choosing between bare copper and tinned copper conductor, the most crucial factors to keep in mind are the type of application and the environment. Copper wires are often preferred over other metals due to their excellent high conductivity and great performance. They are also known for high tensile strength, making them less likely to break under extreme conditions.

International Wire Group provides a range of wire products and services designed with your specific application in mind. Whether you need bare copper or tin-plated copper wire, you can trust us to meet your specific needs. Our dedicated team of engineers and customer service representatives is ready to guide you in making the right choice for your project. To learn more about our bare copper, tinned copper, and other wire solutions, contact us today.