# Non-zero current flow through an electrolytic cell, when an electric potential lesser than that needed for electrolysis is applied?

For instance, the potential needed for water splitting is $$\pu{1.23V}$$. However, there is current flow even at lower potentials (say $$\pu{0.5V}$$). Clearly, there is no redox reaction happening in the cell as evidenced by lack of bubbles. What is the cause of this current?