Copper Magnet Wire Wholesale Supplier, AWG 2-58, Large to small quantities, excellent shipping methods.
Many sizes In-Stock. Various Insulations available such as: FEP, Formvar, Nomex and Polyurethane 155 - 240deg.

Magnet wire is a copper wire covered with thin insulation. It is used in the construction of transformers, inductors, motors and electromagnets; among other applications. However, it is not magnetic itself.

The wire itself is most often fully annealed, electrolytically refined copper. Aluminum magnet wire is sometimes used for large transformers and motors. However, because of its lower electrical conductivity, an aluminum wire must have 1.6 times the cross sectional area as a copper wire to achieve comparable DC resistance. Smaller diameter magnet wire usually has a round cross section. Thicker magnet wire is often square or rectangular (with rounded corners) to permit more efficient use of available winding space. Older insulation materials consisted of cotton, paper or silk and were useful for lower temperature applications (up to 105°C). Modern magnet wire typically uses one to three layers of polymer film insulation, often of two different compositions, to provide a tough, continious insulating layer.

Magnet wire insulating films use (in order of increasing temperature range) polyurethane, polyamide, polyester, polyeseter-polyimide, polyamide-polyimide (or amide-imide), and polyimide. Polyimide insulated magnet wire is capable of operation at up to 250°C. The insulation of thicer square or rectangular magnet wire is often augmented by wrapping it with a high-temperature polyimide or fiberglass tape, and completed windings are often vacuum impregnated with an insulating varnish to improve insulation strength and long-term reliability of the winding.


Copper Magnet Wire


Certified OFHC* (CDA 10100)
The most important characteristic of oxygen-free high-conductivity copper is that it can be heat treated in a reducing atmosphere without embrittlement. Certified OFHC at 99.99% minimum purity displays the inherent qualities of copper to the highest degree.

OFHC* Copper (CDA 10200)
OFHC copper is produced by converting cathodes under very controlled conditions, thereby nearly eliminating all other elements. Where electrolytic copper has purity of 99.0%, OFHC copper has a minimum purity of 99.95%. (Silver is counted as copper.)

ETP Copper (CDA 11000)
Electrolytic Tough Pitch copper is the most widely-used copper for electronic products based on its optimum combination of workability, performance, and economy. For those manufacturing applications in which the presence of from 0.02% to 0.05% oxygen is not critical, ETP copper is specified for most intermediate and end users.


NEMA MW 1000


About Nema MW 1000

MW 1000 is the world's premier standard for general requirements, product specifications and test procedures for the manufacture and packaging of magnet wire. First published in 1965, MW 1000 is a dynamic document that is continually developed and maintained by the NEMA Magnet Wire Section Technical Committee, to ensure that specifications and test procedures reflect evolving magnet wire end user requirements and state-of-the-art magnet wire manufacturing technologies.

MW 1000 is designed to present, in concise and convenient form, all existing NEMA Standards for magnet wire, including standards for round, rectangular, and square film insulated and/or fibrous covered copper and aluminum magnet wire for use in electrical apparatus. MW 1000 contains the definitions, type designations, dimensions, constructions, performance, and test methods for magnet wire generally used in the winding of coils for electrical apparatus.

MW 1000 is approved as an American National Standard through an Accredited Canvass of the American National Standards Institute (ANSI). The Canvass body consists of magnet wiretakeholders including wire and test equipment
 manufacturers, end users, government, testing laboratories and others.


What is Magnet wire?
Magnet wire (also known internationally as winding wire) is an insulated electrical conductor, usually copper or aluminum that when wound into a coil and energized, creates a useful electromagnetic field. Without magnet wire, electricity is essentially useless. Around 90% of all electrical energy requires modification using magnet wire to be of any use.


Comparsion to international standards.
NEMA specifications and test methods differ from those published by the IEC. The following is a general summary of these differences:

Dimensions: NEMA dimensional requirements apply American Wire Gauge (AWG) wire sizing, while dimensional requirements in IEC standards apply metric sizing in mm. Therefore the requirements are not exactly the same, but some overlap occurs between the standards. The IEC and NEMA methods for determining dimensions are technically equivalent.

Resistance to Refrigerants: Both the NEMA and IEC procedures use monochloro-difluoromethane (refrigerant R22). Since R22 is no longer permitted in new equipment, an investigation is underway to identify suitable alternative refrigerants commonly used in newer refrigeration equipment, to test magnet wire for hermetic applications. The challenge is establishing which refrigerants lead to meaningful test results.

Available Specifications: Appendix C of NEMA MW 1000 cross-references NEMA and IEC magnet wire specifications. Not all NEMA specifications have a corresponding IEC specification number and vice versa.

Solderability Requirements: NEMA immersion time requirements for larger wires are more stringent than those specified in IEC specifications. The IEC and NEMA methods for determining the solderability of a given wire construction are technically equivalent and both standards recognize the use of lead-free solder alloys upon supplier/customer agreement.

Continuity Requirements: The NEMA continuity requirements for single build (Grade 1) wire more closely reflect the capabilities of present day manufacturing equipment than do IEC requirements. However, closer harmony between NEMA and IEC requirements for heavy and triple build (Grade 2 and 3) constructions was achieved when a new edition of IEC 60317-0-1 was published in 2013.

Test Procedures: There is an ongoing effort to harmonize IEC and  NEMA test procedures. The following summarizes notable differences in these procedures:

Heat Shock: Differences exist between the test specimen preparation procedures, namely the degree of pre-elongation of wire specimens and the diameter of the test mandrels used for wrapping wire specimens. The NEMA-specified total elongation of wire specimens (pre-stretch + mandrel wrapping) is more stringent than IEC, which specifies only a mandrel wrap.

IEC TC 55 decided not to specify pre-stretching that would result in total elongations equivalent to those in MW 1000.

Dielectric Breakdown: MW 1000 has adopted a shot electrode methodology for determining breakdown of rectangular and large round wires, based on IEC 60851-5.

Thermoplastic Flow (Cut Through): IEC 60851-6 test methods for thermal properties has a single-point method of evaluation. This could be adopted in MW 1000 in the future as a routine test, however for now MW 1000 recognizes a rising-point method as a qualification test.


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