Calculates cathodic protection current density required to polarise a structure to a protection potential of −850 mV vs Cu/CuSO₄ reference. Bare steel requires ≈ 50–150 mA/m² for protection in seawater — pipeline coatings reduce current requirement to 0.5–5 mA/m², dramatically reducing anode mass and power.
Inputs
Area M2
Two-dimensional surface extent (m²). For complex shapes, break into simpler sub-shapes and sum.
I Cp Ma M2
Mass per unit volume (kg/m³). Water: 1,000. Air: 1.225. Steel: 7,850. Affects buoyancy, flow, and structural loads.
Coating Eff Pct
Useful output divided by total input, as a percentage. 100% is impossible due to losses (heat, friction, resistance).
E Pipe V
Reference formula or conversion factor shown for context.
E Prot V
Reference formula or conversion factor shown for context.
Results
total CP current required (A)
Electric charge flow rate (A). Governs wire sizing — too much current causes dangerous heating. Fuses protect circuits from overcurrent.
recommended rectifier current (A)
Electric charge flow rate (A). Governs wire sizing — too much current causes dangerous heating. Fuses protect circuits from overcurrent.