Recommended fuse or circuit breaker rating (A) given the load current and cable section, with cable capacity check (Iz) per IEC 60364-5-52.
Recommended rating (A)—
Cable capacity (Iz) (A)—
IEC 60364 verdict—
Formula
Coordination rule : I_load ≤ In ≤ Iz
I_load = load current
In = rated current of protection device (nearest standard ≥ I_load)
Iz = cable's continuous current capacity (depends on section + install method)
Reference: IEC 60364-4-43, IEC 60364-5-52
Returns the recommended standard rating for the protective device (fuse or MCB) based on the load current, and verifies that the chosen cable section can carry it (Iz check per IEC 60364-5-52 simplified table).
Note: The Iz values used here assume Copper / PVC insulation / multi-core cable in air at 30°C (method B2). For different installation methods or temperatures, consult the full IEC 60364-5-52 tables and apply the appropriate correction factors.
