Enamelled Copper Wire

Not sure which kind of enamelled copper wire you need? Then you’ve made a good decision coming to TEMCo, the place for picking enamelled copper wire.

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What is Enamelled Copper Wire?

Enamelled wire has a very thin layer of insulation or enamel. The wire is typically copper or aluminum, while the insulation is either a thin varnish, a polyester or a fiberglass yarn.


Enamelled copper wire is used in applications which require tight coils of wire, in applications such as inductors, motors, speakers, hard disk head actuators, or electromagnets..

Enamelled Copper Wire for Motors Enamelled Copper Wire for Transformers Enamelled Copper Wire for speakers


Conductor Type

Most enamelled wire will be copper, but aluminum is also used in certain applications, such as large transformers and loudspeaker coils.

There are numerous reasons that copper is the most widely used metal in enamelled wire.

Copper is the highest electrical conductivity of all non-precious metals. Because it has a lower conductivity than copper, aluminum wire requires a cross section that is 1.6 times larger for it to create the same current capability as a copper wire, making copper wire more energy efficient aluminum wire.

Copper is also 300% stronger than aluminum, allowing it to withstand more extreme conditions.

TEMCo offers two types of wire produced by Essex: Soderon 155 and GP/MR-200.


Common shapes for enamelled wires are square, round or rectangular. There are wires that are hexagonal, but they are far less common and are used in applications such as voice coils.

Round wire will have more space between the wires simply because of the lack of edges. It will not be wound as tightly as other wires but this is not an issue with higher gauge wires that have the diameter of a strand of hair.

Square copper wires have much less space between the turns of the wire when they are formed in a coil. Square wires are often used in confined spaces and in applications where higher power is required.

Rectangular copper wires can be wound even tighter than square wires. They are arranged in a plane and then laminated into a flat ribbon.

Rectangular Enamelled Copper Wire Round Enamelled Copper Wire

Pictured above: Rectangular wire (left), round wire (right)


The color of an enamelled copper wire has no effect on the wire itself. Color is purely for aesthetic purposes. The insulation, diameter, weight, breakdown voltage, gauge and thermal class will not be affected.

Wires can come in a variety of colors, such as red, green or amber. A specific wire color can be provided if it is preferred or needed, in cases where multiple wires will have to be soldered, as some manufacturers will provide customers with a wire in the color of their choice.

Color Enamelled Copper Wire


Insulation is used to protect the enamelled copper wire from shorting itself out by having its turns each other. It also enhances the thermal endurance of the wire.

When bare wire is coiled, the turns are not able to touch each other since there is no insulation to protect it from shorting out. Turns of insulated wire, on the other hand, can be wound so that the wires do touch. Insulation is especially important for coils that requires hundreds or thousands of wire turns.

There are many different types of insulation to chose from, each with different thermal capacities, diameters, gauges applications. They include:

  • Polyester-imide has high thermal endurance along with solvent resistance. It also has low friction, which makes it easy to wind.
  • Polyamideimide is made for inverter duty applications, as well as motors that may have voltage spikes.
  • Formvar is extremely flexible and has a very high resistance to abrasion.
  • Polyester Nylon contains a dual coat insulation, polyester basecoat and a nylon topcoat. The high thermal properties of the polyester and the high mechanical properties of the nylon are transferred to the wire.
  • Polyester-amide-imide has a dual coat insulation, which contains a polyester basecoat and an outer coating of amide-imide. This insulation has good windability, heat shock resistance and overload capacity.
  • Dacron glass is a served filament that is a combination of glass and polyester fibers. It can be unvarnished or else will be varnished with silicon or organic material. It is flexible and is resistant to abrasion.
  • Polyamide-ML is made of polyimide resins and has high resistance to chemical solvents, as well as burnout, which is why it is used in extreme conditions.

Insulation materials were once made of things like cotton, paper, and silk. Given that they have a thermal rating of 105°C, these insulations have limited functions.

Large power transformers that operate at high voltages may be insulated by oil-impregnated paper or pressboard, examples of electrical insulation paper.

The wires offered by TEMCo come with a polyurethane insulation that is overcoated with polyamide, an insulation with a thermal rating of 155°C. TEMCo also offers wires that have a polyester-imide insulation and a polyamide-imide overcoated. This wire has a thermal rating of 200°C.

Enamelled Copper Wire Bare Copper Wire

Pictured above: Insulated wire (left), bare wire (right)

Wire Gauge

The United States and Canada use American wire gauge (AWG) standards, which give specific specifications for round, solid wire, including their diameter, resistance, weight and current. There are 44 standard wire gauges, the smallest being 0000 and the largest being 40.

As the wire weight and diameter becomes smaller, the AWG number becomes greater. An example of this is a wire with a gauge of 3 and one with a gauge of 38. The wire that is 3 gauge has a diameter of 5.827 millimeters, while a 38 gauge wire has a diameter that measures 0.101 millimeters.

The smallest diameter will be 11.684 mm, while the largest diameter is 0.0799 mm.

The smallest weight will be 640.5005 lbs per 1000 feet, while the largest weight is 0.0299 lbs per 1000 feet.

Temperature Rating/Thermal Class

The temperature at which an enamelled copper wire has a 20,000 hour service life is known as the thermal class, or temperature rating. Service life of the wire can be extended by using the wire at a lower temperature.

Thermal class is measured in degrees celsius. 130°, 155°, 180° or 200° are among some of the more common temperatures.

Copper also has a lower thermal expansion rate than aluminum, which will move around 33% more than copper will.

Copper can also withstand higher thermal temperatures than aluminum as it has a higher melting point.

Bondable Enamelled Copper Wire

Bondable contains an extra adhesive film, which can be epoxy, polyester or polyamide, on top of the usual insulation. The adhesive activates when heated up, bonding the windings of the wire into a self-supporting coil. This eliminates the need for the spindles around which the wire is wound, called bobbins.

The three main techniques for bonding are solvent, oven and resistance.

Solvent bonding will be applied while the wire is winding. if not, then the completed coil will be dipped in the solvent when the wire is fully coiled.

During oven bonding, the wire is fully wound first before it is put into an oven. The size of the coiled wire will determine how long oven bonding takes, generally ranging from 10 to 30 minutes.

Resistance bonding uses an electric current to bond the wire after it has been coiled. How long it will take to complete the process is dependant on the size and design of the coil. Resistance bonding is not typically used for wire that are less than 34 gauge.

Soldering Process

Enamelled copper wire needs to be soldered. Soldering is the process in which two metals are fused together. This done by taking a third metal, which will be melted down, and putting it between the wire and whatever it is being soldered to. When the third metal solidifies, it will fuse the wire to the other application.

Older wire sometimes needs insulation to be removed before the wire can be soldered, but that is not usually the case. The majority of wire being made now has insulations that acts as a flux, and therefore will not need to be removed before the wire can be soldered. GP/MR-200 wire needs its insulation to be removed first, but the Soderon 155 does not.

Breakdown Voltage

There are three types of breakdown voltage, another name for the dielectric strength of wire insulation: Grade 1, Grade 2 and Grade 3. The breakdown voltage grade will increase with thicker insulations.

Breakdown voltage is based on AWG standards, with smaller gauges having higher breakdown voltages.

The insulation thickness, or build, is the diameter of the enamel, which can be calculated by subtracting the total diameter of the bare copper wire from the total diameter of the insulated wire.

Insulation builds are known as single, heavy, triple or quadruple. Single and heavy are the most commonly found.

Where to purchase Enamelled Copper Wire

View TEMCo’s enamelled copper wire selection by clicking the link below. Wires are available in numerous different gauges, temperature ratings and insulations. Find your enamelled copper wire at TEMCo today!

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