Risks of EMFs Around Conductors

Generally, people become concerned if a power line runs within 200 metres or so of their dwelling. While this distance gives experienced field strengths well outside the guidelines produced by the International Commission on Non-Ionising Radiation Protection (5kV/m and 100 micro Teslas), people still become concerned because of doubts concerning the ability of present scientific methods to reliably predict long term health effects. Because of these concerns, significant protests and challenges to power projects can then ensue.

In the case of overhead power lines, the health worries are reinforced by the significant and permanent visual intrusion that they offer. In fact, the major cause for health concerns of people living near pylons may well be psychological, associated with worry over the lines.

In fact, EMFs extend in fields around conductors which decline with the square of the distance. The field strengths at 30 metres from a 400kV power line are around 1.29 kV/m (electrical) and 1.81 micro Tesla (magnetic). The graphic below gives a comparison between the magnetic fields found around Cross-Linked Polyethylene (XLPE) underground cables and overhead lines. The broader spread of fields from overhead cables can be seen.