Copper Foil For Transformer Windings

What is a Copper Strip?

Copper strip is a common electrical material. There are two common types of copper strip, called conductive and non-conductive. A conductive copper strip conducts electricity on the top and bottom of the tape, while a non-conductive copper strip conducts electricity only on one side. LP Industry mainly provides Copper foils for transformer winding, which is also called transformer copper super thin strips, are mainly used in the transformers manufacturing industries.

The commonly used copper grades are ETP Grade (Electrolytic Tough Pitch), C11000, UNS C10200 TU1, temper O state.

The thickness of copper foil is usually between 0.01mm-3.0mm.
The transformer winding copper foil can be customized according to customer requirements of different widths and thicknesses.

copper strip

Main specifications

Conductor Copper Strip/Foil
Grade Cu-ETP/C-11000/E-Cu588
Temper Soft(O); Hard(H)
Dimension Thickness 0.1-4.0mm

Width 20-1500mm

Cu (Min) 99.99%, 99.99%
Standard ASTM,EN 13599,GB-T 18813-2002
Packing In coil, inner diameter,300m,400mm,500mm etc.
Application Winding of transformers, large scale motors, generator and stators etc.

Smaple Test

In order to ensure the quality of copper strips before leaving the factory, samples will be taken for testing, either according to standards or according to customer requirements.

Item Condition of supply Size(mm) Temper Weight Batch No.,
Copper foil C11000 0.5×300 soft 1968.50KGS T008-2663
Chemical Composition (%)
Item Cu P Bi Sb As Fe Pb S
Standard requested >99.95 <0.001 <0.001 <0.002 <0.002 <0.005 <0.005 <0.005
Testing result 99.9923 0.00075 0.00033 0.0001 0.00071 0.0029 0.00066 0.0017
Mechanical Properties
Item Vickers Hardness ensile strength(Mpa Conductivity(%IACS) Elongation%(A50)
Standard requested 45-65 195~260 ≥98 ≥35
Testing result 57.5 242 100 48

Upon products arriving, please dismount to Check at once and store in Dry place indoor.

How does Copper foil for transformer winding work?

Working Principle
Electromagnetic Induction:
Just like traditional wire windings, copper foil windings work on the principle of electromagnetic induction. When an alternating current (AC) passes through the primary winding, it generates a magnetic field, which induces a voltage in the secondary winding.

Winding Process:
Uniform Distribution: Copper foil can be wound tightly and uniformly around the transformer’s core. This uniformity helps in maintaining consistent electrical characteristics across the winding.
Layering: Multiple layers of foil can be wound with insulation between each layer to achieve the desired voltage and current characteristics.


Copper foils are commonly used in transformer windings, especially for high-frequency transformers and certain types of power transformers.
Optimize foil thickness
Minimize number of layers
Use multiple parallel foils and swap layers
Use different foil thicknesses for different turns.
Use a parallel litz or thin foil winding in the vicinity of a gap
Interleave winding (transformers only)
Use a low permeability material for core leg

copper foil for transformer winding