48. Electric and magnetic fields (EMFs) are associated with most electrical apparatus, including power lines, underground cables and domestic appliances. They diminish rapidly with distance from the source. Electric fields are associated with voltage and can cause small micro-shocks in certain instances (see “Other Electrical Effects” below). Magnetic fields vary with the current in the line or appliance. Both can be measured with appropriate meters. A separate guide to EMFs, “EMF The Facts”, is available.
49. While there is ongoing debate over the possibility of a hazard to health from low-level EMFs, the balance of the scientific evidence to date is against there being health effects.
50. The Health Protection Agency (HPA, previously the National Radiological Protection Board) is responsible for monitoring the hazards to health from all forms of radiation, and is highly respected for its independent scientific opinions. The Government relies on the scientific advice of the HPA, and has brought EMF exposure limits into force in the UK accordingly.
51. All of the electricity system, including all overhead lines, complies with these limits. The limits are set to prevent all established effects of EMFs on people, and the HPA advises that there is insufficient evidence of harmful effects (for example, cancer) below these levels to reduce the limits. The Government are considering whether any precautionary measures might be justified in addition to the exposure limits, based on a report from a stakeholder group called SAGE, but have not yet introduced any. Therefore, in the UK at present, there are no restrictions on EMF grounds on building close to overhead lines.
52. National Grid follows the advice of the Government and the HPA. National Grid recognises that some public concern exists over this matter. National Grid, together with the Energy Networks Association, can provide information on the research carried out worldwide on this subject or, alternatively, can direct interested parties to experts, independent of the electricity industry, who can provide advice and guidance.