In reinforced concrete structures exposed to marine environments corrosion initiates when the chloride ion concentration at the surface of the embedded steel bar exceeds a chloride corrosion threshold (CT) value. CT is generally assumed to have a conservative fixed value between 0.2-0.4% by weight of cement. However over the last 40 years there have been extensive experimental investigations on chloride corrosion threshold confirming that CT is not a fixed value and that depends on many variables. The potential of the steel while it is in its passive state is one those; marked reductions in CT are associated with more negative pre-activation potentials. Experimental measurements of the effect can be found in the literature but for a limited set of conditions. Experiments were designed and conducted here for more detailed assessment. The results were analyzed statistically along with previous data to identify trends and corresponding descriptive parameters. A formulation with CT = CT0 10^(E-E0)/bCT was used and values of the respective were parameters proposed.