Induced currents

The quantum energy of 50 Hz electromagnetic fields is too small to break chemical bonds. It is clear that power-frequency EMFs or radiation does not cause ionisation in the same way that x-rays or alpha particles do. Instead, the main known way 50 Hz fields interact with people is by inducing currents.

More on the effects that induced currents have on the body.  Microshocks are a related but different phenomenon.

Any alternating magnetic field will induce an electric field, which in turn produces a current in a conducting medium. The human body is conducting and will therefore have a current induced in it – albeit, usually, a very small one. As shown on the right the current circulates round the body.

In power-frequency calculations, it is common to assume the human body has a radius of 0.2 m and a conductivity of 0.2 S m^-1. Using this model, a magnetic field of 160 microteslas (µT) induces a peripheral current density of 1 mA m^-2. More accurate numerical calculations can be done which take account of the actual shape of the body and the varying conductivities of different tissues.

Alternating electric fields also induce currents in the body. As shown on the right, for a vertical field, they run up and down the body.  The calculation has to take account of the perturbation to the field caused by the body itself. For a typical person standing in a vertical field, a current of 1 mA through the body is induced by 70 kV m^-1; more on numerical calculations.