Hey guys and thank you very much for your answers.
First, I'm glad you confirmed what I said regarding current'd direction.
When I ask how come the Neutral, which is connected to earth, can source electrns during half cycle of sine waveform, I meant to the possitive half where V_phase is larger than V_neutral (earlier you approved that in this possitive half, electrons flow from N to L1).
crutschow, I understand my mistake, its the transfomer's Neutral end that sources the electrons (just like the transformer's L1 end).
If Earth is connected to N, and electrons flow through the N wire, they dont flow also through EARTH on their way to the load?