Experimentally, the anomalous transport has been found to decrease remarkably in transport barriers in context of improved confinement modes such as High (H) confinement mode. The leading paradigm for the reduction of turbulent transport in transport barriers is based on sheared radial electric field Er. The shear in Er can reduce transport either through stabilizing the linear modes, by reducing amplitudes or correlation lengths of turbulence, or by changing phases between the turbulent fluctuations. However, the mechanism by which the radial electric field is formed in the transition is still unclear. In Ref. [1], Er from the radial current balance was solved with a fully kinetic five-dimensional neoclassical Monte Carlo simulation of the tokamak plasma edge in a realistic ASDEX Upgrade divertor geometry. In this paper, as a continuation of that work, the shear is simulated also for JET and the obtained shear values are compared to experimental results for the critical shear. The validity of the analysis is not limited to some special collisionality regime, thin orbit approximation is not needed, effect of Er on ion orbits is correctly modeled also for high Mach numbers, and there is no need to make assumptions to separate different current components which consist of the same current carriers because these are consistently evaluated from the guiding-centre motion. Assuming that turbulence is electrostatic, anomalous transport can be assumed to be ambipolar which means that it does not affect the current balance. Thus, the logic of this paper is that the value of critical shear is determined by turbulence theory, but this value is reached due to neoclassical effects.