⚡ Power frequency (50/60 Hz) magnetic field immunity — PN-EN 61000-4-8

Electronics and EMC PN-EN 61000-4-8

Overview

WHAT THIS TEST IS (clause 1 of IEC 61000-4-8:2009; a matching scope on the PKN card). Immunity requirements for equipment — only under operating conditions — to magnetic disturbances at the power frequencies of 50 Hz and 60 Hz, encountered in residential and commercial premises, in industrial installations and power plants, and in medium- and high-voltage substations. Whether the standard applies to equipment at a given installation site is decided by the presence of the phenomenon (clause 4). The standard does NOT cover disturbances due to capacitive and inductive coupling in cables and other parts of the installation — those are described by other standards on conducted disturbances. The aim is a common, reproducible basis for evaluating equipment for domestic, commercial and industrial use in continuous and short-duration fields; the standard specifies recommended test levels, the test equipment, the test setup and the procedure. It is a basic EMC publication according to IEC Guide 107 — the levels and criteria for specific products are set by product standards.

WHERE THE FIELD COMES FROM (clause 4). The power frequency field is generated by the current in conductors, less often by other devices (e.g. transformer leakage). The current in normal operation gives a steady field of relatively small value; a short-circuit current — a much larger but short-duration field, until the protective devices operate (a few milliseconds with fuses, a few seconds with protective relays). Testing with a continuous field may concern all equipment for public and industrial low-voltage networks and equipment in electrical plants; the highest short-duration values concern mainly equipment at exposed locations in electrical plants. The field from harmonics is in many cases negligible.

TEST LEVELS (clause 5; field strength in A/m, 1 A/m corresponds in free space to a flux density of 1.26 µT): • continuous field (Table 1): level 1 — 1 A/m, 2 — 3 A/m, 3 — 10 A/m, 4 — 30 A/m, 5 — 100 A/m, x — special; • short-duration field, from 1 s to 3 s (Table 2): levels 1–3 — not applicable, 4 — 300 A/m, 5 — 1000 A/m, x — special; • level x can be any — above, below or in between — and may be given by the product specification (for short-duration also the duration). Selection of levels — Annex C, values encountered in practice — Annex D.

TEST EQUIPMENT (clause 6). The field is generated by a current flowing in an induction coil; the equipment under test is placed at its centre (immersion method). Generator — a voltage regulator supplied from the mains, a current transformer and a control circuit for short-duration operation; continuous or short-duration operation. The connection between the transformer and the coil as short as possible, the conductors preferably twisted, so that the current in them does not distort the field. Requirements for the generator (Table 3): • standard square coil 1 m × 1 m, one turn: current in continuous operation from 1 A to 120 A, in short-duration operation from 320 A to 1200 A; • standard rectangular coil 1 m × 2.6 m, one turn: from 1 A to 160 A and from 500 A to 1600 A; • other coils — the current needed to obtain the field strengths in Table 4; • sinusoidal waveform, current distortion factor ≤ 8 %, continuous operation up to 8 h, short-duration from 1 s to 3 s, floating transformer output — not connected to the protective earth conductor PE. Verification of the generator (6.2.3): the current in the standard coils is measured with a current probe and an instrument with an accuracy better than ± 2 %, in other coils — the field strength with a meter with an accuracy better than ± 1 dB; the distortion factor is also checked.

DEFINITIONS WORTH NOTING (clause 3): coil factor — the ratio of the field strength at the centre of the coil plane (without the equipment under test) to the current; proximity method — a small coil moved along the side of the equipment under test to find particularly sensitive areas; ground reference plane (GRP) — a conductive surface whose potential is the common reference for the generator and the auxiliary equipment; it may close the loop of the coil.

WHAT EDITION 2 CHANGED (foreword of IEC 61000-4-8:2009): the scope was extended to 60 Hz; the characteristics, parameters and verification of the generator and the coils were changed; changes were introduced in the test setup (GRP) and in the procedure. Edition 2 replaced edition 1 of 1993 together with amendment 1 of 2000.

EDITIONS (state on 25.09.2026). PKN: PN-EN 61000-4-8:2010 — English version, publication 29-07-2010, 36 pages, KT 104 Electromagnetic Compatibility, introduces EN 61000-4-8:2010 and IEC 61000-4-8:2009 [IDT], without the "Wycofana" [Withdrawn] header; it replaced PN-EN 61000-4-8:1998 (Polish version, withdrawn 29-07-2010) and its amendment A1:2003. The catalogue has no Polish version of the current edition. CENELEC (iTeh catalogue): EN 61000-4-8:2010 published 12-02-2010. IEC: IEC 61000-4-8:2009, edition 2.0 of 03-09-2009, 65 pages, stability date 2027 (IEC website, read on 25.09.2026).

HOW ACCREDITATION SCOPES CITE THE STANDARD. Measurement of 25.09.2026 on the database of PL accreditation scopes (1310 laboratories with entries): 18 entries at 14 laboratories; notations "PN-EN 61000-4-8:2010" (16) and "EN 61000-4-8:2010" (6), in several entries both at once. Subject of the test: electrical and electronic equipment with a list of groups — among others railway rolling stock equipment, military equipment, lighting equipment, in vitro diagnostic devices, laboratory equipment, fire automation and alarm systems. The methodology most often "Odporność na pole magnetyczne o częstotliwości sieci elektroenergetycznej" [Immunity to power frequency magnetic field] (8), with declared levels, among others "do 30 A/m", "do 100 A/m" [do = up to], "(0,1 – 40) A/m" and test levels (1 – 300) A/m and (1 – 1000) A/m. In the same entries stand, among others, EN 50121-4, PN-EN 60255-26, PN-EN IEC 61326-1 and PN-EN IEC 61326-2-6, and other parts of PN-EN 61000-4 (separate entries in this database).

THE KEY OF THE "LABORATORIES" TAB: "PN-EN 61000-4-8" — 13 laboratories and 16 entries, without foreign entries. The tab will not show 1 laboratory (AB 053), which wrote the standard only as "EN 61000-4-8:2010".

WHAT WE DO NOT GIVE. We had a fragment of the text of IEC 61000-4-8:2009 made available by the publisher: the table of contents, the foreword, the introduction and clauses 1–6.2.3 (up to Table 4). We do not have the values of Table 4 (verification currents for the coils), the characteristics of the coils (6.3, Annex B), the test setup (clause 7 — ground reference plane, positioning of the equipment under test and the coil), the laboratory reference conditions and the course of the test (clause 8 — among others coil rotations and field orientations), the evaluation of the results (clause 9) or the test report. We do not give these parameters.

Method principle

The equipment under test, operating under normal service conditions, is placed at the centre of an induction coil (immersion method) through which a sinusoidal current of power frequency (50 Hz or 60 Hz) flows from the generator; the field strength is set to the level from Table 1 (continuous field) or 2 (short-duration, 1–3 s), and the functioning of the equipment is observed. The evaluation criteria are set by product standards.

Applications

• Electrical and electronic equipment for residential and commercial premises, industrial plants and power plants
• Equipment installed in medium- and high-voltage substations and close to conductors carrying high currents
• Products for which product standards require the test — in accreditation scopes among others rolling stock equipment, lighting equipment, IVD devices, laboratory equipment
• Testing according to product standards and generic EMC standards referencing IEC 61000-4-8

Key parameters

Standard

Standard number

PN-EN 61000-4-8:2010 (wersja angielska; wprowadza EN 61000-4-8:2010 i IEC 61000-4-8:2009 [IDT]; zastąpiła PN-EN 61000-4-8:1998 z A1:2003)

Title (PL)

Kompatybilność elektromagnetyczna (EMC) — Część 4-8: Metody badań i pomiarów — Badanie odporności na pole magnetyczne o częstotliwości sieci elektroenergetycznej

Title (EN)

Electromagnetic compatibility (EMC) — Part 4-8: Testing and measurement techniques — Power frequency magnetic field immunity test

Step-by-step procedure

1. Test plan

   Level and type of field (continuous, short-duration) according to the product standard or Annex C; operating modes of the equipment under test and evaluation criteria from the product standard.

2. Verification of the generator and the coil

   Current in a standard coil (± 2 %) or field strength in another coil (± 1 dB), and the distortion factor (≤ 8 %).

3. Test setup

   Equipment under test at the centre of the coil (immersion method); for floor-standing equipment — a ground reference plane. WE DO NOT GIVE the details of clause 7.

4. Test

   Continuous and/or short-duration (1–3 s) field at the selected level; observation of the functioning of the equipment under test. WE DO NOT GIVE the orientations and times of clause 8.

5. Evaluation and test report

   Evaluation according to the criteria of the product standard (clause 9) and test report (clause 10) — WE DO NOT GIVE the details.

Required equipment and apparatus

Health and safety (OHS)

• High currents in the coil with a short-duration field (up to 1600 A) — terminal covers, interlocks, work according to the generator manual
• Strong magnetic field — persons with pacemakers and implants outside the test area
• Equipment under test at mains voltage — safety rules for electrical equipment

Frequently asked questions