4/0 Copper Wire: Essential Guide

4/0 copper wire, a versatile and widely used electrical conductor, has earned its place in numerous applications across various industries. This robust cable, with its notable thickness and impressive electrical properties, is a go-to option for those in need of dependable and enduring connections. The numerical designation of ‘4/0’ represents the cable’s size.

With its excellent conductivity, resistance to corrosion, and ductility, 4/0 copper wire provides numerous benefits and has become a popular choice for electrical professionals. The wire’s high current carrying capacity makes it ideal for heavy-duty operations, including power distribution systems, service entrance installations, and industrial equipment connections. Additionally, its thermal stability ensures a long-lasting performance, even under the most demanding conditions.

In the following, we will delve into the specifics of 4/0 copper wire, its construction, applications, and essential factors that make it a top choice for electrical wiring projects. Furthermore, we will explore the capabilities and industry standards surrounding this prominent electrical wire, so you can make an informed decision regarding its use for your next project.

4/0 AWG Copper Wire Basics

4/0 AWG copper wire, also known as 0000 AWG, is a large and heavy-duty wire size commonly used for high-power electrical applications. The American Wire Gauge (AWG) system designates wire sizes, and the 4/0 AWG copper wire is among the larger sizes available.

Copper is the primary material used in 4/0 AWG wires due to its excellent conductivity and flexibility. This makes it a popular choice for electrical power distribution in residential, commercial, and industrial settings. Copper wire is known for its durability, corrosion resistance, and ability to effectively transmit electrical current with minimal losses.

The size of the wire is determined by its cross-sectional area. In the AWG system, the larger the number, the smaller the wire diameter. Conversely, smaller numbers represent larger wire diameters. The 4/0 AWG copper wire has a diameter of approximately 0.460 inches or 11.7 millimeters. The larger diameter of this wire allows it to carry higher electrical current capacities, making it suitable for applications requiring substantial power transfer.

A common use for 4/0 AWG copper wire is in service entrance cables for residential and commercial buildings. It is also used in electrical grounding systems and connections for large electrical appliances. When selecting copper wire for any application, it is important to consider factors such as current carrying capacity (ampacity), voltage drop, and insulation type. The ampacity of a 4/0 AWG copper wire typically ranges from 195-260 amps, depending on the insulation material and installation conditions.

In summary, 4/0 AWG copper wire is a versatile and reliable choice for high-power electrical applications, due to its size, conductivity, and durability. It is important to select the appropriate wire size and insulation for the specific application to ensure optimal performance and safety.

Physical Properties

Size and Diameter

4/0 copper wire, also known as 0000 AWG, is a large gauge wire often used in electrical applications and power distribution systems. Its size and diameter can be described in both millimeters and inches for easier understanding:

  • Diameter: 4/0 copper wire has a diameter of approximately 11.7 mm or 0.46 inches.
  • Cross-sectional area: Due to its circular shape, the cross-sectional area of a 4/0 wire is about 107 mm² (square millimeters) or 0.166 square inches. Another popular dimension the circular area in kcmil (a thousand circular mil, or thousandths of an inch). For 4/0 wire, the cross-sectional area is about 212 kcmil.


Heavier than smaller gauge wires, the weight of 4/0 copper wire is an essential factor to consider in installation and transportation. The following information outlines the weight characteristics of this copper wire:

  • Weight per unit length: Typically, 4/0 copper wire weighs roughly (depending on insulation) around 0.7 lb/ft (pounds per foot) or 1.04 kg/m (kilograms per meter).
  • Total weight for a given length: To calculate the total weight of a 4/0 copper wire in a project, multiply the weight per unit length by the needed length.

For example, if you require 100 feet of 4/0 copper wire for a project, the total weight would be approximately 70 pounds (0.7 lb/ft x 100 ft).

Remember that these values are approximate and can vary slightly depending on the manufacturer and insulation used.

Construction and Stranding

4/0 copper wire, also known as 0000 AWG, is a large and heavy-duty electrical wire commonly used in residential and commercial applications. Its construction is primarily made up of bare copper strands, providing high conductivity and flexibility for installation in various environments.

The design of 4/0 copper wire typically features stranded construction, meaning it’s composed of multiple smaller strands of copper twisted together. This configuration enhances the wire’s flexibility and tensile strength, allowing it to be easily bent and installed in tight spaces without compromising performance. The actual number of strands within a 4/0 copper wire can vary depending on the manufacturer and specific application requirements, but there are typically 19 strands that comprise a 4/0 conductor.

The cross-sectional area of 4/0 copper wire is measured in kcmil (thousands of circular mils), which simplifies the specification of large wire sizes. In the case of 4/0 copper wire, it has a size of about 212 kcmil, signifying a significant copper content capable of handling high-current applications.

Adherence to standards is crucial for the quality and reliability of 4/0 copper wire. Manufacturers must ensure that their products comply with various industry regulations like ASTM (American Society for Testing and Materials), UL (Underwriters Laboratories), and NEC (National Electrical Code). This ensures that the wire exhibits attributes such as high conductivity, durability, and heat resistance suitable for safe and efficient operation in its intended applications.

In summary, 4/0 copper wire boasts a robust and flexible structure due to its stranded bare copper construction and various stranding options. Compliance with industry standards guarantees the wire’s quality and performance, ultimately making it a reliable choice for many electrical wiring projects.

Industry Specifications

4/0 copper wire is a large and heavy-duty electrical cable with various applications in the industry. To ensure its quality, it must adhere to specific industry standards which are set by renowned organizations, such as the ASTM and the National Electrical Code (NEC).

The ASTM B8 is a specification concerning the conductivity, tensile strength, and dimensions of bare stranded 4/0 copper wire. To be compliant with ASTM B8, 4/0 copper wire must exhibit the following characteristics:

  • Breaking strenght: between 6,459 lbs and 9,154 lbs depending on manufacturing technique.
  • Diameter: about 528 mils
  • Ampacity: the ampacity for bare stranded (vs insulated) is MUCH higher per ASTM B8 standards, 480 amps.

When insulated, the NEC guidelines, 4/0 copper wire holds its importance due to the following ampacity related attributes:

  • Ampacity: 4/0 copper wire typically carries a current of up to 195 to 260 Amps, making it suitable for various heavy-duty applications.
  • Temperature rating: It comes in insulation ratings like 60, 75, and 90 degrees Celsius, depending on the specific application environment. These ratings dictate the ampacity you can use.

In summary, 4/0 copper wire’s quality and performance are assured by compliance with ASTM B-8 and NEC standards. The wire demonstrates high conductivity, adequate tensile strength, and proper dimensions, which make it suitable for various industrial and electrical applications with stringent requirements. The knowledgeable technician ensures the product’s safety, performance, and reliability by adhering to these industry specifications.

Electrical Characteristics

4/0 Copper Wire Ampacity

4/0 copper wire ampacity is approximately 195-260 amps when used in a typical residential application. This makes it suitable for supplying power to heavy-duty equipment and high demand electrical systems. Factors like insulation type and ambient temperature can impact the ampacity. As pulled from the NEC Table 310.16:

  • At 60°C insulation: 195 amps
  • At 75°C insulation: 230 amps
  • At 90°C insulation: 260 amps

It is essential to select the appropriate insulation and temperature rating based on the installation environment. Also note that the numbers above are based on nominal conditions. There are other factors that negatively impact these ratings, such as ambient temperature and bundling with other current-carrying conductors, all of which is discussed in the NEC.

4/0 Copper Wire Voltage

The voltage rating of the 4/0 copper wire refers to the maximum voltage it can safely handle without causing electrical failure. It is generally available with an insulation rating of 600V, 2kV, or variable ratings designed for specific applications.



4/0 copper wire is widely used for grounding applications in various industries due to its excellent electrical conductivity and corrosion resistance. Some common grounding applications include:

  • Electrical panel grounding: Ensuring proper and safe connections to ground for various types of electrical panels.
  • Transformer grounding: Providing a solid connection to ground for transformers, protecting systems from potentially harmful voltage transients.
  • Static discharge grounding: Providing a path to ground for static electricity buildup.

When choosing 4/0 copper wire for grounding applications, it is essential to follow the appropriate application specifications defined by the National Electrical Code (NEC) and other regulatory authorities.

4/0 copper wire is known for its excellent conductivity and durability, making it a popular choice for various electrical applications. The conductor material used in these wires is typically copper, which is known for its high electrical conductivity, thermal conductivity, and resistance to corrosion.

The most common temper for copper conductors is annealed, which provides increased flexibility and resistance to work-hardening. This allows for easier installation and longevity, making annealed copper conductors ideal for permanent wiring systems.

There are various related products on the market that cater to specific applications, among which THHN and MTW wiring are popular choices. THHN (Thermoplastic High Heat-resistant Nylon-coated) wire is commonly used in building wiring for commercial and industrial applications due to its resistance to heat, moisture, and mechanical stress.

On the other hand, MTW (Machine Tool Wire) is a versatile option used across multiple industries for general wiring purposes, such as control cabinets, machine tools, and appliances. It boasts a durable PVC insulation that can withstand oil, moisture, and abrasion.

In summary, 4/0 copper wire, with its high-quality conductor material and annealed temper, offers a reliable and durable solution for various electrical applications. Paired with related products like THHN and MTW wiring, customers have a range of options to suit specific wiring needs in various industries, all while maintaining confidence in their choice of materials and products.

Reference and Resources

Books and Standards:

One valuable resource is the National Electrical Code (NEC), which provides guidelines for the safe installation of electrical wiring and equipment. It contains detailed information about the requirements for 4/0 copper wire, including ampacity, conduit fill, and more.

Another key reference is the Insulated Cable Engineers Association (ICEA) standards, which offer information on the manufacturing and testing of different types of cable, including 4/0 copper wire.

Online Resources:

A useful online platform is the Copper Development Association (CDA) website. It contains a wealth of knowledge about copper and its various properties, including its use in electrical systems. Additionally, the Wire & Cable Manufacturers’ Alliance (WCMA) website offers resources on the wire and cable industry.

Industry Forums:

Participating in specialized industry forums can also be beneficial. These platforms allow engineers, electricians, and other professionals to discuss topics related to 4/0 copper wire, share experiences, and provide guidance to others.

Frequently Asked Questions

How many amps can 4/0 copper wire handle?

4/0 copper wire can typically handle between 195-260 amps depending on the insulation type, ambient temperature, and other factors as defined in the NEC.

What are common uses for 4/0 AWG cable?

Common uses for 4/0 AWG copper wire include but are not limited to service entrance wiring, industrial power distribution, and commercial electrical applications. They can be used in both underground and overhead installations.

What is the diameter of 4/0 copper wire?

The diameter of a 4/0 copper wire, also known as its cross-sectional area, is approximately 0.46 inches or 11.7 millimeters. This measurement refers to the conductor only and does not include the insulation thickness.

Is 4/0 copper wire suitable for 200 amp service?

4/0 copper wire is likely suitable for 200 amp service, but as always, check with the NEC to verify your application. It allows for ample current carrying capacity and is often recommended for this application due to its ability to manage heat and resistance effectively.

How does 4/0 copper wire compare to 4/0 aluminum wire?

Copper is a better conductor than aluminum and has a greater ability to manage resistance and heat. However, aluminum wire needs to be larger gauge to accommodate similar ampacity.

What is the difference between 4/0 copper wire and 2/0 copper wire?

The main difference between 4/0 and 2/0 copper wire is their dimensions and current carrying capacity. 4/0 copper wire has a larger diameter and can handle a higher current compared to 2/0 copper wire. Consequently, 4/0 copper wire performs better in applications that require larger loads and higher current flow.

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