We have determined, via electrophoresis, the zeta-potential at solid/non-polar liquid interfaces. The particles used were either metallic (Al, Ag, Pt) or non-conducting (capacitor paper, polyethylene) ones. The liquid was cyclohexane and its resistivity was modified by the addition of an electrolyte: triisoamylammonium picrate (TiAP). The zeta-potential and thus the electrical charge at the interface, obtained at thermodynamic equilibrium were related to electrical measurements such as the apparent resistivity of the liquid, superficial conduction and ion injection by conducting and non-conducting electrodes.