⚡ Immunity of electrical and electronic equipment to impulse magnetic fields (lightning, faults, switching in substations) — field from an induction coil fed with an 8/20 µs current surge, test levels 100, 300 and 1000 A/m or level X, PN-EN 61000-4-9

Electronics and EMC PN-EN 61000-4-9

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN 61000-4-9:2016-11 (the “Scope” field in Polish translation, quoted as it appears on the card; our English rendering): “This part of IEC 61000 specifies the immunity requirements, test methods and range of recommended test levels for equipment subjected to impulse magnetic disturbances mainly encountered in: industrial installations, power plants, railway installations, medium voltage and high voltage substations. The applicability of this standard to equipment installed in different locations is determined by the presence of the phenomenon, as specified in Clause 4. This standard does not consider disturbances due to capacitive or inductive coupling in cables or other parts of the installation. (…) The object of this standard is to establish a common reference for evaluating the immunity of electrical and electronic equipment when subjected to impulse magnetic fields. (…)” We read the text of the standard in the preview of IEC 61000-4-9:2016 (edition 2.0, 2016-07) from the cover to subclause 6.2.3 (calibration of the generator, page 13) and in the redline version (RLV) to Clause 4.

ACCORDING TO THE TEXT OF THE STANDARD (foreword, clauses 1–6.2.3). The standard was prepared by IEC SC 77B; it has the status of a basic EMC publication (IEC Guide 107) — product committees decide whether the test is applied and set the levels and performance criteria. The second edition replaces the first of 1993 and Amendment 1:2000; as technical changes the foreword lists new annexes: B (field distribution of the coils), D (measurement uncertainty), E (mathematical modelling of the surge waveform), F (characteristics with two standard coils), G (3D numerical simulations), and the treatment of coil factor calculation and calibration using current measurement. The test is to determine the reaction of the equipment under test (EUT) under specified operating conditions to impulse magnetic fields caused by switching and lightning; the standard does not deal with disturbances coupled capacitively or inductively in cables. According to Clause 4, impulse fields are generated by lightning strikes on buildings and metal structures (masts, earth conductors, earth networks) and by initial fault transients in low, medium and high voltage systems, and in high-voltage substations also by switching of bus-bars and lines by circuit breakers; the test mainly concerns electronic equipment installed in electricity generation and distribution plants and their control centres, it is not relevant for distribution network equipment (e.g. transformers, lines); product committees may consider other applications. Test levels (Table 1, peak field strength): levels 1 and 2 — not applicable, 3 — 100 A/m, 4 — 300 A/m, 5 — 1 000 A/m, X — special (above, below or between the others, given in the equipment specification); 1 A/m corresponds in free space to a flux density of 1,26 µT; the level is chosen according to the installation conditions (installation classes in Annex C). Instrumentation (6): the combination wave generator (same waveform as in IEC 61000-4-5) works as a current source — only the 8/20 µs current waveform is relevant, measured as short-circuit current without the coil connected; generator parameters: positive and negative polarity, phase shifting 0°–360° relative to the a.c. line voltage of the EUT with a tolerance of ±10°, repetition at least once per minute, short-circuit peak current from 100 A to 1 000 A or the required level divided by the coil factor, peak current tolerance ±10 %, floating output; front time Tf = 1,25 × Tr = 8 µs ± 20 %, duration Td = 1,18 × Tw = 20 µs ± 20 % (Tr — between 10 % and 90 % of the peak, Tw — between the half-peak points); an 18 µF capacitor in the output circuit; for calibration of the generator the current probe must not saturate, its lower (−3 dB) corner frequency must be below 100 Hz, and the oscilloscope or other instrument must have a bandwidth of at least 1 MHz; calibration is done for all levels applied. The definitions (3.1) include among others the coil factor (ratio of the field strength at the centre of the coil plane without the EUT to the current) and the proximity method (a small coil moved along the side of the EUT to find particularly sensitive areas); the RLV shows as text deleted from the previous edition the definitions of the “immersion method” (EUT at the centre of the coil) and the “decoupling network”. The table of contents then lists: 6.3 — induction coil (field distribution, standard coils 1 m × 1 m and 1 m × 2,6 m), 6.4 — calibration of the test system, 7 — test setup (table-top EUT, floor-standing EUT, in-situ test — 7.5), 8 — procedure (climatic and electromagnetic laboratory conditions, execution), 9 — evaluation of results, 10 — test report, Annexes A (non-standard coils, coil factor), B, C (selection of test levels), D, E, F, G.

STATUS (cards as of 02.10.2026). The card of PN-EN 61000-4-9:2016-11 (English version) has no “Withdrawn” header — the standard is CURRENT: published 24-11-2016, 62 pages, price group V, Information and Communication Technologies Sector, KT 104 for Electromagnetic Compatibility, ICS 33.100.20, “Introduces: EN 61000-4-9:2016 [IDT], IEC 61000-4-9:2016 [IDT]”, “Replaces: PN-EN 61000-4-9:1998/A1:2003 - Polish version, PN-EN 61000-4-9:1998 - Polish version”. There is no Polish version of the 2016 edition in the catalogue: the PKN search for “PN-EN 61000-4-9” (02.10.2026) shows 2016-11 (English), 1998 (Polish) and amendment A1 (Polish 2003, English 2002). Card of PN-EN 61000-4-9:1998 (Polish version; EN 61000-4-9:1993, IEC 61000-4-9:1993): “Withdrawn and replaced by PN-EN 61000-4-9:2016-11 - English version”, withdrawal date 24-11-2016; card of amendment PN-EN 61000-4-9:1998/A1:2003 (Polish version): “Withdrawn and replaced by PN-EN 61000-4-9:2016-11”, withdrawal date 24-11-2016, “Scope”: “The content of the clauses on climatic conditions, evaluation of test results and test report was changed”. What the change to the 2016 edition means for the result — according to the foreword: coil factor calculation and system calibration with current measurement and new annexes (field distribution, uncertainty, two coils); we do not have the content of these points. We have not checked the status of IEC 61000-4-9:2016 on the IEC website. Nor have we checked whether the standard is listed among the standards harmonised under the EMC directive.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 02.10.2026). The number 61000-4-9 appears in 11 records of 9 laboratories: AB 022, AB 053 (2), AB 117, AB 167, AB 171, AB 261 (2), AB 295, AB 310, AB 1604. Current scopes on the PCA website (read 02.10.2026, scope issues from 30.12.2024 to 08.09.2026): the number stands in 12 lines — at AB 117 twice in one item (“PN-EN 61000-4-9:1998” and “PN-EN 61000-4-9:1998+A1:2003”), at AB 053 and AB 261 in two items. Editions in PCA: 2016-11 — AB 022, AB 167, AB 171, AB 261, AB 310; 2016 without month — AB 295 (“PN-EN 61000-4-9:2016”) and AB 053 (written “EN 61000-4-9:2016”, without “PN-”); the withdrawn 1998 with A1:2003 — AB 117 and AB 1604. None of these items is suspended (at AB 171 the footnotes on the suspension of part of the scope from 13.05.2026 concern lines in bold italics — the line with 61000-4-9 is not set that way). The “Laboratories” tab searches for entries BEGINNING WITH “PN-EN 61000-4-9” and shows 8 laboratories — without AB 053, which writes “EN 61000-4-9:2016”; checked with the tab query on the production server labcoda.pl on 02.10.2026: “PN-EN 61000-4-9” — 8, “EN 61000-4-9” — 3 (AB 053 and two Czech laboratories accredited by ČIA, No. 1341 and 1695), “PN-EN IEC 61000-4-9” — 0.

WHAT THE LABORATORIES TEST (items in PCA). Object: electrical and electronic equipment — at eight of them, including low-voltage equipment with lighting, IT and traction equipment (AB 022), electronic equipment of rolling stock and other product groups (AB 053, two items), with input current ≤ 16 A (AB 117, AB 295), medical devices (AB 1604), equipment for military use (AB 171 — in one item with many defence standards and other parts of PN-EN 61000-4), tests at the laboratory and at the installation site (AB 261, “IN SITU”); at AB 310 the object is “Industrial and railway installations, power plants, medium and high voltage substations” with the “direct method”. Test levels in the scopes: up to 1000 A/m (AB 053, AB 117, AB 310; AB 295 — “up to 1 kA/m”, “SURGE type”), (100–1000) A/m (AB 261), levels 3, 4, 5 and X from 100 to 1000 A/m (AB 167), (100–2200) A/m (AB 1604, with the 1998 edition with A1:2003) — a value above level 5 is level X in Table 1, defined by the equipment specification; AB 022 and AB 171 give no level.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With the instrumentation: the generator is calibrated with the short-circuit current without the coil, and the field strength follows from the current and the coil factor — a peak current set without taking the coil factor into account (required level divided by the factor) gives a field strength different from the declared level; a saturating probe, one with a lower corner frequency above 100 Hz, or an oscilloscope with a bandwidth below 1 MHz distort the measured 8/20 µs shape; tolerances: front time and duration ±20 %, peak current ±10 %. In the procedure: the generator must provide both polarities, phase shifting relative to the line voltage (0°–360°, ±10°) and repetition at least once per minute — how many surges, in which polarities and phases are applied in the test is set by Clause 8, which we do not have, as are the evaluation criteria (Clause 9). With the level: levels 1 and 2 in Table 1 are “not applicable”, and level X and the performance criteria are set by the product committee or the equipment specification — a result “immune at 1000 A/m” without a performance criterion does not say how the equipment behaved. With the edition: AB 117 and AB 1604 cite the 1998 edition with A1:2003 (withdrawn 24.11.2016), which according to the card of amendment A1 had different wording on climatic conditions, evaluation of results and the report than the 1998 edition without the amendment; the 2016 edition added among others system calibration with current measurement.

WHAT WE DO NOT GIVE. From the 2016 edition we do not have the points from 6.3 onwards (coils, field distribution, system calibration), Clauses 7–10 (table-top, floor-standing and in-situ setups, laboratory conditions, execution of the test, evaluation of results, report) or Annexes A–G (coil factor, installation classes, uncertainty). We therefore do not give the setup dimensions, coil positions, number of surges or the performance criteria.

Method principle

A combination wave generator working as a current source feeds an 8/20 µs surge (front time 8 µs, duration 20 µs) into an induction coil of known coil factor, which produces in the volume of the equipment under test an impulse magnetic field with a peak strength of 100, 300 or 1000 A/m (or level X from the product specification); the generator provides surges of both polarities and with phase shifting relative to the line voltage, and the operation of the equipment is observed under specified operating conditions and evaluated against the criteria set for the product.

Applications

• Electronic equipment for electricity generation and distribution plants, medium and high voltage substations, industrial and railway installations (scope of the standard) — in the scopes: rolling stock, control equipment, AB 310 — installations and substations
• General-purpose, medical and military electrical and electronic equipment — immunity tests according to the product specification (9 laboratories)
• Test at the installation site (“IN SITU”) — AB 261

Key parameters

Standard

Standard number

PN-EN 61000-4-9:2016-11 (wersja angielska; EN 61000-4-9:2016, IEC 61000-4-9:2016 IDT)

Title (PL)

Kompatybilność elektromagnetyczna (EMC) — Część 4-9: Metody badań i pomiarów — Badanie odporności na impulsowe pole magnetyczne

Title (EN)

Electromagnetic compatibility (EMC) — Part 4-9: Testing and measurement techniques — Impulse magnetic field immunity test

Step-by-step procedure

1. Choice of level

   Test level from Table 1 (100, 300, 1 000 A/m or X) according to the installation conditions (classes in Annex C) and the product specification; performance criteria — from the product committee. PN-EN 61000-4-9:2016-11 current (card as of 02.10.2026).

2. Generator calibration

   Short-circuit current without the coil: 8/20 µs (±20 %), peak current ±10 %, for each level applied; probe < 100 Hz (−3 dB), bandwidth ≥ 1 MHz.

3. Coil current

   Peak current = required field strength divided by the coil factor; coil factor and field distribution of the coils — subclause 6.3 and Annexes A, B (content NOT GIVEN).

4. Setup and test

   Table-top EUT, floor-standing EUT (with reference ground plane) or at the installation site (Clause 7); number of surges, polarities and phases from Clause 8 NOT GIVEN (the generator must allow both polarities and phase shifting).

5. Evaluation and report

   The operation of the EUT is evaluated against the criteria in the product specification (Clause 9), report — Clause 10 (content of both NOT GIVEN).

Required equipment and apparatus

Health and safety (OHS)

• The surge generator produces high voltages and currents up to 1 000 A — work according to the equipment instructions; the read text of the standard contains no health and safety warnings
• TECHNICAL NOTE: the field strength depends on the current and the coil factor — the generator current alone is not the test level; AB 117 and AB 1604 cite the 1998 edition with A1:2003, withdrawn 24-11-2016

Frequently asked questions