Taped Litz Wire


Taped high frequency Litz wire constructions are mainly suitable for applications requiring a high break down voltage. Taping gives Litz wire improved capability to withstand flexing and mechanical stress. Self-adhesive tape material increases protection against re-opening during and after manufacturing processes and thus secures the compliance with defined creepage distance.

Some tapes can be thermally sealed, when used in conjunction with certain wire enamel types.

The individual wires excellent adhesion and bonding characteristics can be achieved. Thermally sealed tapes can be selected from a number of material types for special applications all promoting various degrees of flexibility and mechanical protection for the Litz wire construction.

Features and Benefits of Tapes

VariantsDielectric strengthFlexibilitySplicingContacting
Standardhighvery goodgoodvery good
Thermally Sealedelevatedmediumvery goodvery good
Self-Adhesivevery highgoodvery goodgood


Diameter of single wires0.040-0.500mm
Outer diameter of litz wire0.50-10.0mm
Overlapping single tape50 or 67%
Numbers of tapes (max.)2


  • Inverters
  • RF transformers
  • RF transducers
  • RF chokes
  • Inductive charging
  • Onboard charger
  • DC/DC converters

Technical Data Sheet of Tapes

DescriptionPolyesterPolyethylene NaphthalatPolymide
Breakdown voltagekV5.0
(VDE 0345)
(JIS C 2318)
(ASTM D 149)
Insulation class (UL)°C105 (A)180 (H)200 (C)
Insulation class (VDE)°C130 (B)-200 (C)
Dielectric constantεr3.3
(VDE 0345)
(JIS C 2318)
(ASTM D 150-92)
(VDE 0345)
(IEC 60695-11-10; UL94)
UL-File No. Tapes*E53895E206562E39505
Processingfusiblefusiblemechanical stripping
Thermally SealedPETPENPI
Breakdown voltagekV5.4
(ASTM D 149-81)
(ASTM D 149)
Insulation class (UL)°C105 (A)-200 (C)
Insulation class (VDE)°C130 (B)-200 (C)
Dielectric constantεr3.26
(ASTM D 150-81)
(ASTM D 150-92)
(IEC 60695-11-10; UL94)
UL-File No. Tapes*E93687-E39505
Processingfusible-mechanical stripping
Breakdown voltage1kV5.05.05.0
Insulation class (UL)°C180 (H)180 (H)180 (H)
Dielectric constantεr3.2
(JIS C 2318)
(JIS C 2318)
(JIS C 2318)
Flammability-flame retardant
(UL 501)
flame retardant
(UL 501)
UL-File No. Tapes*E93687E206562E39505
Processingfusiblefusiblemechanical stripping

1 approximate value
* the used foils are variants of UL recognized products
Other materials on demand

Special constructions with VDE-approval for high voltage applications available:
EFOLIT-product family

VDE – certified acc.: DIN EN 60950, annex U
DIN EN 61558, annex K
DIN EN 60601, annex L

Taped high frequenzy litz wire EFOLIT


VDE-certified triple reinforced insulated high frequency litz wire with self adhesive sPET and sPEN film material for diameters up to 5.0 mm. Constructions with self adhesive tapes allow very high break down voltages as well as high flexibility. Compliance with application specific demands for air and creepage distances is covered in perfect manner.


according to specification:

DIN EN 62368, Annex J
DIN EN 60950, Annex U
DIN EN 61558, Annex K
DIN EN 60601, Annex L

Dimensional range EFOLIT

Diameter single conductor0.030 - 0.300 mm
48 - 28 AWG
Total conductor cross section0.100 - 10.600 mm²
Outer diameter Litz Wire (approx.)0.500 - 5.000 mm
24 - 4 AWG
Tape insulation (min.)3-layers

Operating range EFOLIT

Winding Wires for reinforced insulation
Max. rated and peak voltage1000 Vrms,
1414 V peak
Max. frequency500 kHz
Temperature classF / 155°C / 311°F
H / 180°C / 356°F

Labeling EFOLIT

Validated StandardsCodesPETsPEN
DIN EN 60950, 61558,


VDE-Reg.-No.: E078
(nom. test voltage 6,0 kV)
EFOLIT 11Fclass F with enamel type
TI ≥ 155°C / 311°F
EFOLIT 21H-class H with enamel type
TI = 155°C / 311°F
EFOLIT 22H-class H with enamel type
TI ≥ 180°C / 356°F
DIN EN 60950

VDE-Reg.-No.: E450
(nom. test voltage 3,0 kV)
EFOLIT 13Flass F with enamel type
TI ≥ 155°C / 311°F
EFOLIT 23H-class H with enamel type
TI = 155°C / 311°F
EFOLIT 24H-class H with enamel type
TI ≥ 180°C / 356°F

TI = Temperature Index

Technical Data Tape Material

Self-Adhesive TapesPETsPEN
DescriptionPolyesterPolyethylene Naphthalate
Break down voltage5.0 kV5.0 kV
Temperature class (UL)130°C / 266°F (B)180°C / 356°F (H)
Permittivity (JIS C 2318)3.22.9
Flammability (UL 510)-flame retardant
UL File No. Tape*E 93687E 206562

* The used tapes are variants of UL recognized products

Litz Wire Attributes

Typical Litz wire:105 x 0.08 mm OSP18
Overal diameter litz wire:1.05 to 1.15 mm (approx. AWG 18)
Elongation:10 %
Resoftening temperature Smartbond:> 130°C / 266°F
Solderability:4 sec. at 420°C / 788°F
Breakdown voltage (non-bonded twist):1,200 V
Elongation:18 %
Cut through temperature:260°C / 500°F
Bond strength (helical coil):1,700 cN after 180°C / 356°F hot air bonding
1,900 cN after 210°C / 410°F hot air bonding
Litz wire diameter:0.50 mm to 3.50 mm
Base insulation of single wire:high temperature modified Polyurethane
P180 for temperature class 180°C / 356°F (H)
Bond coat on litz wire:modified thermoplastic
Bonding temperature:> 170°C / 338°F
Approvals:UL listed
SGS-data available

Technical values of a typical product

 Standard litz wireServed litz wireSelfbonding litz wireSmartbond
Stability of coil-goodmediumgood
Flexibility / windabilitysoftmore stiffsoftsoft
Bonding process-solventhot airhot air
Mechanical protectionavggoodavggood
Surface and haptic-roughavgsmooth
Second adhesion step without additional adhesivenonolimitedyes

Degree of Overlapping

The degree of overlapping of two adjacent tape windings is defined by the gradient angle between tape and litz wire during the taping process. The overlapping determines the number of tape layers located on top of each other and thus the insulation thickness of the litz wire.

50% Overlap67% Overlap