IEC TR 63167:2018 pdf download

IEC TR 63167:2018 pdf download.Assessment of contact current related to human exposure to electric, magnetic and electromagnetic fields
1 Scope
This document, which is a Technical Report, provides general information on the assessment of contact current related to human exposure to electric, magnetic and electromagnetic fields. The contact currents in this context occur when a human body comes into contact with a not electrified conductive object exposed to an electric and/or magnetic field at a different electric potential owing to electric and/or magnetic induction to the object. This is distinguished from the issue of electrical safety where contact with live parts of a conductive object is dealt with. In reference to the international EMF guidelines [1 ]-[4] 1 , the frequency range of contact current covered in this document is direct current to 1 1 0 MHz, and only steady-state (continuous) contact currents are covered. Transient contact currents (spark discharges) which may occur immediately before the contact with the object are not covered.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 contact current current flowing into the body resulting from contact with a conductive object in an electric, magnetic or electromagnetic field 3.2 electric field strength magnitude of a field vector at a point that represents the force (F) on an infinitely small charge (q) divided by the charge 3.3 exposure state that occurs when a person is subjected to an electric, magnetic or electromagnetic field, or to a contact current other than those originating from physiological processes in the body and other natural phenomena 3.4 indirect effect effect resulting from physical contact between a person and a not electrified object, such as a metallic structure in an electric, magnetic or electromagnetic field, at an electric potential that is at least at a point of the object different from the potential of the person 3.5 touch current electric current flowing through a human body when it touches one or more accessible parts of an installation or of equipment Note 1 to entry: The term “leakage current” had also been used as a synonym for touch current in the field of electrical safety. 3.6 spark discharge transfer of current through an air gap prior to making contact with another conductive object at a different potential
5 Contact current in EMF exposure guidelines
Clause 5 overviews contact currents described in the EMF guidelines [1 ]-[4]. In the frequency range up to approximately 1 0 MHz (dominantly up to 1 00 kHz), the flow of electric current from an object in a field to the body of an individual may result in the stimulation of muscles and/or peripheral nerves. With increasing current, this may be manifested as perception, pain from an electric shock and/or burn, the inability to release the object, difficulty in breathing and, at higher currents, cardiac ventricular fibrillation. In the frequency range of about 1 00 kHz to 1 1 0 MHz, shocks and burns can result either from an individual touching an ungrounded metal object that has acquired a charge in a field or from contact between a charged individual and a grounded metal object. In the EMF guidelines, reference levels for steady state (continuous) contact current are given for frequencies up to 1 1 0 MHz to avoid shock and burn hazards (see Annex A). The reference levels are not intended to avoid ventricular fibrillation, which is the basis of standards for electrical safety. The upper frequency of 1 1 0 MHz is the upper frequency limit of the FM broadcast band. Here, the transient currents resulting from spark discharges [5].