Standard tolerances

Categories: Heating materials , Resistance materials

Standard tolerances for wire are provided below. Size tolerances do not apply to material manufactured to resistance tolerances and vice versa.

Tolerances on electrical resistance

  • Resistance of Wire at 20°C (68°F)
  • Diameter ≤ 0.127 mm (0.005 in): ± 8%
  • All dimensions > 0.127 mm (0.005 in): ± 5%

Tolerances on dimensions

Tolerances on diameter of wire according to the EN 10 218-2 T4 standard

Wire size Max deviation from nominal value Max ovality
  MM IN MM IN
d Tol = ±0.015·√d (Tol = ±0.002976·√d) Tol ≤ 0.015·√d (Tol ≤ 0.002976·√d)

Max ovality = a - b