The insulation layer thicknesses and the corresponding electrical efficiencies are divided into degrees. Depending on the grade, there is a different ratio of copper cross-sectional area to total cross-sectional area. The insulation grades describe a minimum and a maximum value for the increase of the layer thickness. According to the common IEC 60317 standard, grade 1 has the thinnest and grade 3 the thickest insulation layer. However, wires with thinner or thicker insulation or reduced tolerances are also available on a customer-specific basis.
In many calculations, the enamel layer is not taken into account and the effective outer diameter is therefore calculated too tightly.
As shown in this table by the fine wire manufacturer Elektrisola, a 0.100 G1 wire with 0.1 mm copper and an insulation layer has an effective outer diameter of 0.108 mm to 0.117 mm.
Copper Winding Wires
Flat Wire
NEMA MW 1000
What grades of insulation are
