Exposure limits and policy

UK policy

Government policy on EMFs in the UK includes exposure limits and precautionary measures. The policy was formed with advice from the UK Health Security Agency (UKHSA) and the Stakeholder Advisory Group of Experts (SAGE) on Extremely Low Frequency Electric and Magnetic Fields. You can read more about these organisations here

This page sets out the current policy for overhead lines and underground cables.


What is the policy and where is it set out?

The policy is set out in the Written Ministerial Statement of 2009 (formally, this was the Government's response to SAGE's First Interim Assessment), which was reaffirmed in National Policy Statement EN-5. 

The policy for high-voltage overhead lines has two key pillars: compliance with the 1998 ICNIRP exposure guidelines in the terms of the 1999 EU Recommendation, and a precautionary policy called "optimal phasing". 

For low-voltage distribution networks (132 kV and below), the agreed precautionary measures are set out in Engineering Recommendation G92 published by the Energy Networks Association.


Exposure limits

Exposures to the general public in the UK should comply with the ICNIRP 1998 exposure limits in the terms of the 1999 EU Recommendation.
In practical terms this means:

  • An electric field of 9 kV/m.
  • A magnetic field of 360 µT.
  • Both applying where the time of exposure is significant e.g., residential properties, and properties where members of the public spend an appreciable proportion of their time.


Precautionary measures

The UK has embraced the concept of precautionary measures, but has specified which precautionary measures will be applied to different types of equipment. In summary, the measures which apply are:

  • High-voltage overhead power lines: optimum phasing.
  • High-voltage underground cables or substations: no additional precautionary measures.
  • Low-voltage distribution: a series of engineering measures designed to reduce net currents.
  • House wiring: no specific measures.
  • Distribution substations: encouragement to site them away from homes where possible, but no specific requirements.