Our smallest wind turbines need to be a minimum of 400 metres away from residential properties, ideally 500 metres or more to be sure there will be noise complaints.
They also need to be 110% of tip height away from roads, train tracks, powerlines etc., so a minimum of 110 metres.
Finally they need to be at least 3 rotor diameters apart, if perpendicular to the prevailing wind. Or if a turbine is placed behind another in line with the prevailing wind then they need to be 5 rotor diameters apart.