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What happens next

  • A personal response within one business day
  • We’ll walk through the full calculation workflow with you
  • Answer any BS7671 methodology questions you have
  • Discuss the right licence option for your practice
  • Your account is activated and you can start calculating immediately
  • No hard sell - just a straightforward technical conversation

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What CableSpec calculates

  • CCC: Ib ≤ In, Ib ≤ Iz (Reg 433.1.1)
  • Overload: In ≤ Iz × Cf × Cc (Regs 433.1.201–204)
  • VD: Ir·cosφ + Ix·sinφ reactive formula (App 4 §6.4)
  • Zs ≤ Zs_max: correct time per earthing & type (Reg 411.3.2)
  • CPC: S ≥ √(I²t)/k or Table 54.7 (Regs 543.1.3–4)
  • PFC at load end vs breaking capacity (advisory)