Cable Ampacity Calculator

Calculate the maximum safe current a cable can carry by its cross-sectional area.

°C
Current Capacity

Formulas

  • Base ampacity from BS 7671 Table 4D2A (clipped) or 4D5 (conduit)
  • Temperature correction: Ca = √((90−Ta)/(90−30))
  • Grouping correction: Cg (from table above)
  • Design current capacity = Base × Ca × Cg