Copper Magnet Wire

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Soderon 155 » GP/MR-200 »


What is Copper Magnet Wire?

Copper magnet wire is covered with a layer of insulation or enamel and is used to convert electric energy into magnetic energy.


Applications that have tight wire coils will use copper magnet wire. Transformers, inductors, motors, speakers, hard disk head actuators, or electromagnets are among the applications that use coiled copper magnet wire.

Copper Magnet Wire for Motor Copper Magnet Wire for Speaker Copper Magnet Wire for Transformer

Magnet Wire Specifications

Conductor Type

Copper is the default metal for most wire, but aluminum is used in some applications as well, including large transformers and loudspeaker coils.

The reason that copper is so widely used is that it is the highest conducting non-precious metal, second overall only to silver. Aluminum, on the other hand, has a much lower overall conductivity than copper does. Aluminum wire requiring a cross-section that is 66% larger than a copper wire would need in order to achieve equal ratings.

Wires that are made from metals, like copper, that are good electrical conductors will run more efficiently than metals that are don't conduct electricity as well, like aluminum. Poor electrical conductors will result in wasted heat.


Copper magnet wire are normally square, round and rectangular. The wire shapes is important in determining how tightly the wire can be coiled.

Square copper wire: less space between the windings as they are formed into a coil. Often used in confined spaces. Applications that require higher power, and that have a larger capacity and wire gauge, will also need square wire coils.

Round wire: more spaces between the wires makes it so that it cannot be wound as tightly as square wire.

Rectangular wire: flat ribbon that is the most easily wound. Found on edge-wound coil springs.


The color the copper magnet is purely aesthetic. The color of the wire will have no effect on the insulation, diameter, current, or any other aspect of the wire's functionality.

Common copper wire colors include red, green and amber. In some cases, manufacturers will provide customers with a wire in a specific color if it is required.

Color Copper Magnet Wire


Insulation is put on copper wire to protect it while it is winding. Turns of bare wire, meaning wires without any insulation, are not able to touch each other, since the wire would short out if they did. Wires need hundreds or thousands of turns to coil, so copper wire needs the protection that the insulation provides.

Extra high-temperature tape made of polyimide or fiberglass is sometimes used on wires with thicker insulations. These wires also have a varnish covering that is designed to both increase the strength of the wire, as well as the endurance.

Cotton, paper, and silk are among the older materials used to insulate wire. These are only useful for low-temperature applications, though, since their thermal rating is only around 105°C.

Copper magnet wire insulations are varnish or a yarn. Formvar, polyurethane, polyester, and polyester-imide are some of the many different kinds of insulation that a copper magnet wire might use. Wires can also be double coated, meaning they will have both an undercoat and a topcoat.

TEMCo sells wires that have a polyurethane insulation with a polyamide overcoat called Solderon 155, and polyester-imide insulation overcoated with polyamide-imide, called GP/MR 200.

Wire Gauge

American wire gauge (AWG) is used in the U.S. and Canada to represent the specifications of a round wire, such as diameter, resistance and current.

As wire diameter and weight decrease, the the wire's gauge increases. A wire with a diameter of 4.621 millimeters will have an AWG size of 5, for example, while a wire with a diameter that measures 0.143 millimeters will have an AWG size of 35.

American wire gauge sizes go from from 0000, which will have a diameter of 11.684 mm, to 40, which has a diameter of 0.0799 mm.

0000 gauge wires have a weight of 640.5005 lbs per 1000 feet. The 40 gauge wire has a weight of 0.0299 lbs per 1000 feet.

Copper Magnet Wire Gauge

Temperature Rating/Thermal Class

The temperature at which a wire will have a 20,000 hour service life is called the thermal class, or temperature rating. Wires generally have temperature ratings of 130°, 155°, 180° or 200°, all in degrees celsius.

If the wire is used at a lower temperature, this will extend the wire's service life.

Bondable Copper Magnet Wire

There are three main bonding processes: solvent, oven and resistance.

The solvent bonding coat will be applied in one of two ways: either during the winding process, or else the coiled wire will be have to be dipped in the solvent after the winding is finished.

For oven bonding and resistance bonding, the wire is fully wound and is then heated up, thus allowing the coil to bond. Oven bonding requires the wire to be put into an oven, while resistance bonding involves giving the coil an electric current.

Oven bonding can take 10 to 30 minutes, with the time depending on the coil's size. Resistance bonding time depends on both the size of the wire and the coil's design. Resistance bonding won't generally be done on a wire that has a gauge of less than 34.

Soldering Process

When a wire is soldered, it means that it is being fused to another metal. This is done by melting a third metal, which will then connect the other two together.

In most cases, enamel does not have to be removed from the wire before the soldering process, but it really just depends on the type of wire. The GP/MR-200 does have to have the insulation removed, while the Soderon 155 wire does not.

Breakdown Voltage

Breakdown voltage is an indication of the dielectric strength of the wire's enamel insulation. The breakdown voltage can be of 3 types: Grade 1, Grade 2 and Grade 3. The thicker the insulation, the higher the grade. Higher ambient temperatures can lead to a reduction in breakdown voltage.

The dielectric strength of the wire's enamel insulation is also called its breakdown voltage.

The breakdown voltage grade 1, grade 2 or grade 3. The thicker the insulation build, the higher the grade will be.

The insulation build is the measurement of the insulation that has been added to the bare copper wire. It can be either single, heavy, triple or quadruple, with single and heavy being the commonly uses. The total diameter of the insulated wire, minus the diameter of just the bare wire, will give you the insulation build.

Wires with smaller gauges have higher breakdown voltages, given that smaller gauges have larger diameters.

Where can I purchase my Copper Magnet Wire?

TEMCo offers wire in a wide range of gauges, temperature ratings and insulations. View our product selection below to purchase your magnet wire. Don't see what you need? Call TEMCo for a quote on any type of wire today!

View Soderon 155 Wire Selection View GP/MR-200 Wire Selection

Call us at 877.474.8209