1 Scope
Interest in magnetic fields has been stimulated in recent years by concern over the
physiological effects they may have on humans and animals and the deleterious effects
they have on the performance of some electrical equipment, particularly video display
units. Investigations have yielded results which are presented in this report as reference
values.
NOTE 1 The European Union EMC Directive has prompted magnetic field measurements, particularly
in respect of the commercial office environments associated with supply authority
substations and electrical distribution systems within buildings. Supply authorities
have sponsored most of the work and the results are generally within the frequency
range of 50 Hz to 2 kHz, and presented as r.m.s. values. There is, however, a need
to have some knowledge about d.c. fields and the fields up to 150 kHz as they may
interfere with some types of equipment.
NOTE 2 Most of the magnetic field data in this report is associated with sinusoidal current
sources and r.m.s. values may be assumed unless otherwise stated.
Power supply systems operating at voltages less than or equal to 1 000 V are designated
low-voltage, those above 1 000 V and up to 35 kV are designated medium-voltage, and
those in excess of 35 kV are designated high-voltage.
Open preview (PDF)Electromagnetic compatibility (EMC). Environment - Low frequency magnetic fields in various environments