Magnetic Wire

Looking to purchase magnetic wire, but not sure which kind you need? TEMCo has the guide for picking the right kind for you. Call us at 877.474.8209 or view our online product selection below.

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Soderon 155 » GP/MR-200 »


What is Magnetic Wire?

Magnetic wire is copper or aluminium wire coated with a very thin layer of insulation or enamel. It is used to change electric energy into magnetic energy.

Magnetic Wire Applications

Magnetic wire can be found in applications which require tight coils of wire, for example transformers, inductors, motors, speakers, hard disk head actuators, or electromagnetics.

Magnetic Wire for Motor Magnetic Wire for Speaker Magnetic Wire for Transformer

Magnetic Wire Specifications

Conductor Type

Magnetic wire is most commonly made out of copper, but can also be made from aluminum. Aluminum wires are typically used on large transformers.

Aluminum has a lower conductivity than copper, which is the highest conducting non-precious metal, so to create the same current capability as a copper wire, aluminum wire requires a cross section that is 1.6 times larger. Aluminum does, however, have more resistance to corrosion than copper.


Magnetic wire can be square, round or rectangular. The shape of the wire will determine how tightly the wire can be coiled.

Square copper wires will have less space between the turns when they are formed in a coil and are typically used in confined spaces. They will also be found in applications that require higher power and that have a larger capacity.

Round wire, on the other hand, will have more space between the wires and cannot be wound as tight.

Rectangular copper wires are arranged in a plane and are then laminated into a flat ribbon of flexible insulating plastic. Rectangular copper wire is the most easily wound since it lays flat. Edge-wound coils springs use flattened wire.


The color of magnetic wire will have no bearing on the insulation or any other element of how the wire will function. The different colors make it easier to differentiate the wires during soldering. Wires can come in a variety of colors, including red, green and amber.

If a certain wire color is required, manufacturers will sometimes be able provide customers with a wire in a specific color.

Color Magnetic Wire


Magnetic wire insulations are either a thin varnish, a yarn made out of polyester or fiberglass, or both.

Square or rectangular wires with thicker insulations can sometimes come with an additional high-temperature polyimide or fiberglass tape. The windings are often covered with an extra insulating varnish that is meant to improve the strength and long-term reliability of the winded wire.

The insulation serves to enhance the thermal endurance of the wire and protect the wire from shorting itself out. Some wires are bare, meaning they have no insulation, but in those cases the turns of the wire would not be able to not touch each other. Insulated wire can be wound so that the wires are touching. In the case of a wire needing to have hundreds or thousands of turns, the wire will require protection from insulation.

Different insulation types will have different thermal capacity, diameter (which can be measured in millimeters or inches), AWG wire size, and application.

Some common types of insulation include polyester and polyurethane.

TEMCo offers the Soderon 155 line, which has a polyurethane insulation with a polyamide overcoat, and will a thermal rating of 155°C. We also offer the GP/MR-200 line, which comes with a polyester-imide insulation overcoated with polyamide-imide, which has a thermal rating of 200°C. Both of these wires come with a double coat of insulation.

Increased wire strengthen and increased durability are the main reasons for wire to have double insulation. On top of that, the wire also takes on characteristics of both insulations. The GP/MR 200 has higher dielectric properties and chemical resistance to common solvents and refrigerants because of its insulation, while the Soderon 155 is resistant to solvents and has very high windability.

Older insulation materials used to be made of things like cotton, paper, or silk. These are only useful for low-temperature applications with a thermal rating of 105°C.

Wire Gauge

Wire diameter can be determined by the American wire gauge (AWG) rating of the wire. AWG is used in the U.S. and Canada to represent specific characteristics of round wire, such as diameter, resistance and current.

Diameter and AWG number work inversely: as the wire diameter decreases, the AWG number increases. For example, a wire with a diameter of 5.827 millimeters will have an AWG size of 3, while a wire with a diameter that measures 0.101 millimeters will have an AWG size of 38.

There are 44 standard wire gauges in all, ranging from 0000-40. The smallest gauge wire will have a diameter of 11.684 mm, while the largest gauge wire has a diameter of 0.0799 mm.

Magnetic Wire Gauge


Like the wire diameter, wire weight will be based on AWG standards and will have an inverse relationship with the gauge, meaning as the gauge becomes greater, the weight of the wire will decrease.

Wire is calculated by weight, rather than length. This is done for accuracy, since weighing wire is a simpler process than measuring out miles of wire.

The largest wire weight is 640.5005 lbs per 1000 feet, with a gauge of 0000. For a 40 gauge wire, the weight is 0.0299 lbs per 1000 feet.

Temperature Rating/Thermal Class

The thermal class, or temperature rating, indicates the temperature of the wire at which it will have a 20,000 hour service life. If the wire is used at a lower temperature, then the service life of the wire will be extended.

130°, 155°, 180° and 200° are some common temperatures found in different types of insulation. The maximum thermal class is 250°.

Thermal class is measured in degrees celsius.

Bondable Magnetic Wire

Bondable wire contains an extra adhesive film on top of the usual insulation that activate when heated up. It will bond the turn to turn windings of the wire into a self-supporting coil. eliminating the need for bobbins, the spindles around which the wire is wound.

Bonding agents include epoxy, polyester and polyamide.

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

A solvent bonding coat will be applied while the wire is winding, or else the coiled wire will be dipped in the solvent after the winding has completed.

For oven bonding, the wire is fully wound and then will be put into an oven to allow the wire to bond. Oven bonding can take 10 to 30 minutes, depending on the size of the coiled wire.

Resistance bonding requires an electric current to heat up the completed coil, which will then cause the wire turns to bond. The amount of voltage and time necessary to complete the process are dependent on the size of the wire and the design of the coil. Resistance bonding is typically used for wire sizes 34 gauge or higher.

Soldering Process

Wire will be soldered to another wire or to a metal circuit board. A third metal will be melted down to merge the wire with the other metal. The third metal will have with a lower melting point; lead or tin is commonly used.

Depending on the type of wire, insulation may or may not need to removed before the wire can be soldered. The GP/MR-200 wire offered by TEMCo does require that the insulation be removed from the wire first before the wire can be soldered, while the Soderon 155 wire TEMCo offers does not.

Breakdown Voltage

Breakdown voltage indicates the dielectric strength of the enamel insulation of the wire. The breakdown voltage can be of 3 types: Grade 1, Grade 2 and Grade 3. The thicker the insulation, the higher the breakdown voltage. Higher ambient temperatures result in a reduction of breakdown voltage.

The insulation thickness, or build, is the measurement of the enamel that has been added to the circumference of the bare wire. It can be determined by subtracting the total diameter of the wire from the diameter of the insulation and wire added together.

Insulation build can be single, heavy, triple or quadruple, with single and heavy being the most common.

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

Where can I buy Magnetic Wire?

Click the links below to view the magnetic wire selection from TEMCo. We offer wires in numerous different gauges, temperature ratings and insulations. 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