When you are close to a power line, the height above ground makes a big difference to the field. When you are farther away, the height makes much less difference. The same thing applies to the clearance of the power line above ground. This graph shows the effect of changing either the height above ground or the clearance of the line by 1 m on the magnetic field. This is calculated for a typical power line. The details would vary from line to line but the principle is the same.
You are here: / / / / / How the effect of height varies with distance from a power line