WG C4.25 Issues related to ELF Electromagnetic Field exposure and transient contact currents


Microshocks are electrical discharges that occur when a person in a high electric field comes close enough to another conducting object that is at a different voltage for a discharge to occur and for transient contact current to flow between the person and the object. In power line or substation work they can be controlled by good practices involving bonding or isolation. Although microshocks experienced by general public may sometimes be felt as annoying or painful, they do not generally constitute a health hazard.  However, contact currents have sometimes to be limited especially for persons wearing a medical device. 

Contact currents related to high electric field are addressed by the international recommendations (ICNIRP, IEEE) and more recently also by the European Directive on the EMF exposure of Workers (2004/40/EC), although they presently address only steady state contact currents.  It is likely that transient currents will also be considered in future revisions of such guidelines.

Pacemakers and other implants are becoming more common. Interferences caused in them by high electric or magnetic fields may happen close to high voltage or high power equipement. Malfunctions appear to be rare but can have serious consequences.  Collecting information on cases related to ELF electromagnetic fields would be useful. Most studies concern steady state fields. Also the impact of contact currents and microshocks on implants will need to be assessed based on data if available

Neither microshocks nor interferences of implants have been studied in detail by Cigre. There is a need to identify and provide guidance on how to mitigate microshocks and how to assess the risks related to interferences of implants. Hence, there is a need to set up a WG addressing these items.


The study will be divided in two parts. One will evaluate the importance and the wave shapes of the different contact currents and recommend mitigation methods that can be used for different situations where high electric fields (AC, DC) occur in substations, on transmission towers and under overhead lines. The other part will address issues related to ELF electromagnetic fields and implants.

Convener: K. Kopsidas (UK)

Progress Report 2013 (pdf, 57kB)

Progress Report 2014 (pptx, 99kB)

Progress Report 2015 (pptx, 100kB)

Progress Report 2016 (pptx, 100kB)