Insulation Taping Method of NOMEX Paper Covered Conductor Continuously Transposed Cable:
Note: 
Total thickness indicates the thickness of the two sides together. One side of the insulation is half of the total thickness.
1 mil = 0.0010 inches. 
Example: - In the following section the insulation thickness is referred as P10. it means the total insulation thickness of the paper insulation that is required is 10 mil. On each side of the conductor, we need 5 mil of insulation covering. 

A. For conductors with total Nomex insulation thickness of 8 mil (N8)
Interleaved taping as shown in figure 1 on page 3 shall be provided. Each layer’s insulation shall be 2mil with the total insulation thickness to achieve required insulation thickness. 

B. For conductors with total Nomex insulation thickness of 12 mil (N12) & above
One layers of 2 mil Nomex with butt-lap taping for inner layer as shown in figure 2 on page 3 and 2 outer layers of 2 mil Nomex with interleaved tapping as shown in figure 1 on page 3 shall be provided.

C. For conductors with total paper insulation thickness of 8 mil (P8)
2 of 2mil interleaved taping as shown in figure 1 of page 3. Thermally upgraded kraft paper (TKP) shall be used for all layers.

D. For conductors with total paper insulation thickness of 10 mil (P10)
Interleaved taping as shown in figure 1 on page 3 shall be provided. The layer insulation paper shall be one layer of 2 mil and one layer of 3 mil or two layers of 2.5mil. Thermally upgraded kraft paper (TKP) shall be used for all layers.

E. For conductors with total paper insulation thickness of 12 mil (P12)
Use two layers of 2mil with interleaved taping as show in figure 1 of page 3 (or) one inner layer of 2mil with butt lap as shown in figure 2 on page 4 and last two outer layers of 2mil with interleaved taping as shown in figure 1 of page3. Thermally upgraded kraft paper (TKP) shall be used for all layers.

F. For conductors with total paper insulation thickness of 20 mil (P20)
Inner layer of 2mil interleaved as shown in figure 1 on page 3 and last 2 outer layer of 3mil interleaved as shown in figure 1 on page 3 and thermally upgraded kraft paper (TKP) shall be used for all layers.

G. For conductors with total paper insulation thickness of 24 mil (P24) & above
Inner and outer layers should be interleaved as shown figure 1 on page 3 with 50% interleaving. Thermally upgraded kraft paper (TKP) shall be used for all layers. 

Note: 
1) The points C to F which are mentioned page 2 & page 3 applicable to circular coils. 
2) Conductors for rectangular coils, conductor insulation on the last two outer layers should be Munksjo (55HDC)/Denison (12HDC) upgraded high density crepe paper. 
3) For rectangular coils, VTC will clearly inform on the ordering sheet about the type of coil to the vendor. 
4) Tolerance on the total paper covering after wrapping with all inner and outer layers = -5% to +5%. Interleaving of paper shall be designed with 50% overlap to achieve insulation tolerance of ±5%.
5) Minimum number of layers should be 3 and the direction of the paper shall be reversed after 4 layers. Exceptions to this are P8, P10 and P12.
6) VTC approved paper per table MS010.400.07 and its thicknesses of 2mil, 2.5mil and 3mil to be used to build the thicknesses for categories C through G.