PHY(domestic circuit)

Only the hole of live was connect to the AC voltage source, the neutral is kept to be zero voltage. The voltage of the live is AC, from +200 to -220V in HK. Neutral acts as the return path back to the power station for completing the circuit.

The potential of the neutral hole is ALWAYS kept at earth potential (i.e. zero volt). As such, there is no potential difference between your finger and your body when you touch the neutral hole. No current would flow through your body.