In case of a standard hydrogen electrode

In electrochemistry, the standard hydrogen electrode (SHE) is conventionally assigned a standard electrode potential (E) of exactly zero volts at all temperatures to serve as a reference point [2]. However, this is a notional definition rather than a physical reality. The absolute electrode potential, which represents the potential difference between the electrode and a point outside the electrolyte (such as an electron at rest in a vacuum), is not zero [5]. Scientific estimates place the absolute potential of the SHE at approximately 4.44
0.02 V at 25 C [3]. While the standard potential is defined as zero by convention to facilitate the comparison of redox couples, the actual energy required to move a charge from the electrode surface to infinity (the absolute potential) remains a non-zero value [5].

Sources

1. [1] https://en.wikipedia.org/wiki/Electrode_potential
2. [2] https://en.wikipedia.org/wiki/Standard_hydrogen_electrode
3. [3] https://en.wikipedia.org/wiki/Absolute_electrode_potential
4. [5] https://pmc.ncbi.nlm.nih.gov/articles/PMC2562797/
5. [4] https://www.nature.com/articles/npre.2010.4354.1