- The paper is concerned with convection induced by non equilibrium electroosmosis at, an ion exchange electrodialysis membrane, as a source of over limiting conductance through the membrane. Derivation of non equilibrium electroosmotic slip condition is recapitulated along with the results of linear stability analysis of quiescent electrodiffusion. through a flat ion exchange membrane. Results of numerical calculation pertaining to nonlinear convection, developing from the respective instability, are reported along with those of recent experiments with modified membranes. These latter rule in favor of surface versus hl~ origin c of over limiting conductance through ion exchange membranes.