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

Variants Dielectric strength Flexibility Splicing Contacting
Standard high very good good very good
Thermally Sealed elevated medium very good very good
Self-Adhesive very high good very good good


Diameter of single wires 0.040-0.500 mm
Outer diameter of litz wire 0.50-10.0 mm
重叠的单带 50 or 67 %
Numbers of tapes (max.) 2


  • Inverters
  • RF transformers
  • RF transducers
  • RF chokes
  • Inductive charging
  • Onboard charger
  • 直流/直流转换器

Technical Data Sheet of Tapes

Description Polyester Polyethylene Naphthalat Polymide
Color transparent transparent brown
Standard PET PEN PI
Breakdown voltage kV 5.0
(VDE 0345)
(JIS C 2318)
(ASTM D 149)
Insulation class (UL) °C 105 (A) 180 (H) 200 (C)
Insulation class (VDE) °C 130 (B) - 200 (C)
Dielectric constant εr 3.3
(VDE 0345)
(JIS C 2318)
(ASTM D 150-92)
Flammability °C 400
(VDE 0345)
- V-0
(IEC 60695-11-10; UL94)
UL-File No. Tapes* E53895 E206562 E39505
Processing fusible fusible mechanical stripping
Thermally Sealed PET PEN PI
Breakdown voltage kV 5.4
(ASTM D 149-81)
- 5.0
(ASTM D 149)
Insulation class (UL) °C 105 (A) - 200 (C)
Insulation class (VDE) °C 130 (B) - 200 (C)
Dielectric constant εr 3.26
(ASTM D 150-81)
- 3.4
(ASTM D 150-92)
Flammability n.a. - V-0
(IEC 60695-11-10; UL94)
UL-File No. Tapes* E93687 - E39505
Processing fusible - mechanical stripping
Self-Adhesive PET PEN PI
Breakdown voltage1 kV 5.0 5.0 5.0
Insulation class (UL) °C 180 (H) 180 (H) 180 (H)
Dielectric constant εr 3.2
(JIS C 2318)
(JIS C 2318)
(JIS C 2318)
Flammability - flame retardant
(UL 501)
flame retardant
(UL 501)
UL-File No. Tapes* E93687 E206562 E39505
Processing fusible fusible mechanical stripping

1approximate 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 conductor 0.030 - 0.300 mm
48 - 28 AWG
Total conductor cross section 0.100 - 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 voltage 1000 Vrms,
1414 V peak
Max. frequency 500 kHz
Temperature class F / 155°C / 311°F
H / 180°C / 356°F

Labeling EFOLIT

Validated Standards Code sPET sPEN
DIN EN 60950, 61558,


VDE-Reg.-No.: E078
(nom. test voltage 6,0 kV)
EFOLIT 11F class 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 13F lass 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 Tape sPET sPEN
Description Polyester Polyethylene Naphthalate
Color transparent transparent
Break down voltage 5.0 kV 5.0 kV
Temperature class (UL) 130°C / 266°F (B) 180°C / 356°F (H)
Permittivity (JIS C 2318) 3.2 2.9
Flammability (UL 510) - flame retardant
UL File No. Tape* E 93687 E 206562
Processing fusible fusible

* 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 wire Served litz wire Selfbonding litz wire Smartbond
Stability of coil - good medium good
Flexibility / windability soft more stiff soft soft
Bonding process - solvent hot air hot air
Mechanical protection avg good avg good
Surface and haptic - rough avg smooth
Second adhesion step without additional adhesive no no limited yes

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% Overlap 67% Overlap