Essex is the European leader for Continuously Transposed Cable (CTC), mainly used in transformer' applications. Thanks to its expertise gained over more than 50 years of experience, Essex is selected as a supplier by global companies for their most demanding projects. 
Besides, the Energy Wire dedicated R&D department of Essex is able to develop with the customers specific designs and insulation. 
The Essex production ranges from 5 to 84 strands. The width of strands varies from 3.10 to 12.50 mm and the thickness from 1.00 to 3.30 mm.  

Quick Links 
  CTC Spools & Packaging 
  CTC Product Information 
  Metal Information  
  Energy Wire Brochure 

A wide range of conductors, strand insulation, insulation materials and assembled CTC is available to cover most of the customers' needs.
Furthermore Essex is able to propose a global approach thanks to the energy wire production plants in Asia and America. 
  Enamelled flat wires plants   
Material  IEC Standard 
Transposed Cable   n.a.
Cellulose Paper     60554-3-5
Press Board  60641
Magneform® F-120  60317-18
  Magnetemp CA-200   60317-29 
Magnebond® FX-120  60317-18 (based coat)
Magnebond® FX2-120  60317-18 (based coat)  

Size Range 
Width  Thickness  Section  Width/Thickness 
3,10 - 12,50 1,00 - 3,30 mm 3,50 - 39 mm² 2:1 - 8:1      

Transposed Cable 
Strands  Axial Size  Offset  Pitch 
≤79 mm ≤26 mm  15 - 50 mm ≥5x width

 Wrapping material  
Type of Paper  Special Feature 
Kraft General purpose with high purity 
Calandered Kraft   Higher density and dielectric strength 
 Upgraded   Better thermal properties 
 Upgraded, calandered   Higher density, thermal and dielectric characteristics 
 Calandered, upgraded, creped   Outer layers with very high mechanical strength 
 Epoxy coated upgraded Kraft   Bondable outer layers 
 Aramide   Very high thermal resistance, for traction transformers 
 Epoxy coated aramide   Bondable outer layers, for traction transformers 
 Perforated pape   CTC with improved cooling of LV windings 
 Glass fabric tape   External protection for cast resin transformers  

Size Calculation 
  CTC Size Calculation 

Radial Tolerance 
Transposing factor FT ≥ 7
thickness of strand ≤
 2,00 mm or 
yield point 
Rp0,2  170 MPa
 Transposing factor  FT ≥ 5 thickness of strand > 2,00 mm, or  
yield point 170 < />Rp0,2   220 MPa  
No. of Strands Tolerance mm No. of Strands Tolerance mm
 ≤ 21   -0,10/+ 0,20   ≤ 21   -0,10/+ 0,30 
 ≤ 35   -0,15/+ 0,30   ≤ 35   -0,15/+ 0,50 
 ≤ 55   -0,20/+ 0,80   ≤ 55   -0,20/+ 1,30 
 > 55   -0,50/+ 1,10   > 55   -0,50/+ 1,40 

In case of transposing factors FT  < 5="" or="" yield="" point="" />0,2 > 220 MPa, please contact  Essex for technical support. 
Axial tolerance: - 0,10/+ 0,05 mm, all sizes.