How can we decrease the voltage between neutral & earthing wire?
Voltage between neutral and earthing is called stray voltage how can we reduce it.

If the neutral and earth is not connected together at one point, there will be a potential difference. Look into connecting both at one point.

If the neutral and earth is not connected together at one point, there will be a potential difference. Look into connecting both at one point.
Neutral is commonly derived from the transformer common or center tap. The earthing wire is bonded to the system ground normally consists of several ground rods bonded with copperweld ground wires. If the system ground resistance is less than 5 ohms, the voltage between neutral and earthing wire should be negligible if not zero. I would suggest to do a ground resistance test if the system ground resistance is acceptable. If ground resistance is > 5 ohms, additional ground rods maybe needed to lower the ground resistance to the desired < 5 ohms. Caution: connection between neutral and earth ground is not arbitrary