Health and Safety

The health and safety of the public is very important to Northern Ireland Electricity and we are committed to protecting your health and safety at all times.

We design and operate the electricity network in Northern Ireland to the highest safety standards and continually review and update the network in accordance with Government standards.

Electric and Magnetic Fields (EMF) occur in the natural world, and people have been exposed to them for many thousands of years. The advent of modern technology and the wider use of electricity and electrical devices have inevitably introduced changes to naturally occurring EMF patterns. Energised HV power-transmission equipment is a source of power-frequency or extremely-low-frequency (ELF) alternating EMF, which add to, or modulate the Earth's steady natural fields.

Electric field strengths are measured in volts per metre (V/m) or kilovolts per metre (kV/m). The atmospheric electric field at ground level is normally about 100V/m in fine weather, but may rise to many thousand volts per metre during thunderstorms. Magnetic fields are usually measured in microteslas (µT). The Earth has a natural magnetic field, which is approximately 50 µT in the island of Ireland.

EMFs are also produced in everyday situations by electrical wiring and electrical appliances. Domestic electrical appliances and tools can generate EMF in normal use broadly comparable to those produced by transmission lines 50m away.

There are no statutory regulations in the UK that limit the exposure of people to power frequency EMF. Responsibility for implementing appropriate measures for the control of EMF lies with Government, who act on the scientific advice of the Health Protection Agency, formerly the National Radiological Protection Board (NRPB). The exposure guidelines in place in the UK as a result of Government policy, formulated in 2004 and reiterated in 2009, are those published in 1998 by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), applied in the terms of the 1999 European Union Recommendation.

The ICNIRP guidelines recommend that the general public are not exposed to levels of EMFs able to cause a current intensity of more than two thousandths of an ampere per square metre (2 mA/m2) within the human central nervous system. This recommendation is described as “the Basic Restriction” and broadly corresponds to the effects of an electric field of 9 kV/m or a magnetic field of 360 µT.

For the Northern Ireland section of the Tyrone Cavan Interconnector, the peak electric field, which occurs directly underneath the proposed overhead line, will be 7.8kV/m, and the peak magnetic field will be 47 µT. Both of these levels are within ICNIRP guidelines and comply with UK Government policy.

The question of possible health effects arising from environmental power-frequency fields has been thoroughly reviewed in recent years by a number of national and international bodies, including the NRPB, the International Agency for Research on Cancer and the World Health Organisation (WHO). The UK Government has considered carefully whether any mitigation measures are necessary in response to the possibility of health effects, and in a statement published in 2009 concluded that no precautionary measures are appropriate in relation to HV overhead lines beyond compliance with the existing exposure guidelines.

The advice of the NRPB, endorsed by various UK Government ministers when answering Parliamentary Questions, gives no reason on grounds of a health hazard as to why the proposed overhead line should not be constructed and operated, given that it complies with the relevant exposure guidelines. This conclusion has been further endorsed by the Secretary of State for Trade and Industry, who in various recent decisions has not regarded the evidence on possible health risks as sufficient grounds to refuse to grant either Consents or Necessary Wayleaves for HV overhead lines.

The Tyrone Cavan Interconnector will comply with the ICNIRP and EU guidelines on exposure of the general public to EMF. Such compliance meets UK Government policy for providing the appropriate level of protection for the public.

Additional information sources:
Energy Networks Association www.energynetworks.org
World Health Organisation www.who.int