Surge and burst tests: IEC 61000-4-5 and 61000-4-4
IEC 61000-4-5 (surge) and IEC 61000-4-4 (EFT/burst) are the two basic EMC publications for conducted transient immunity. They define waveforms, generators, coupling networks, setups and a range of test levels, but they do not decide which level a product must pass: generic and product standards do. This page gives the current editions with their dates, the level tables cell by cell, the procedure rules that test plans most often get wrong, the levels actually required by the generic standards cited under the EMC Directive, and a list of common claims that the texts contradict.
Editions and status, dated
Section titled “Editions and status, dated”| Publication | Edition | Date | Status on 7 October 2026 |
|---|---|---|---|
| IEC 61000-4-5 | 2.0 | 2005 | Replaced by edition 3.0 |
| IEC 61000-4-5 | 3.0 | 15 May 2014 | Current, amended by AMD1:2017 |
| IEC 61000-4-5 | 3.1 (consolidated, 2014 + AMD1:2017) | 4 August 2017 | Current consolidated version; IEC stability date 2027 |
| IEC 61000-4-4 | 2.0 | 2004 (+ AMD1:2010) | Replaced by edition 3.0 |
| IEC 61000-4-4 | 3.0 | 30 April 2012 | Current; IEC stability date 2026 |
Edition 3.0 of IEC 61000-4-5 added four annexes against 2005: mathematical modelling of surge waveforms (Annex E), measurement uncertainty (Annex F), calibration of impulse measuring systems (Annex G) and coupling/decoupling for lines rated above 200 A (Annex H). The surge test for ports connected to outdoor telecommunication lines, previously in 6.2, moved to a normative Annex A that specifies the 10/700 µs generator. Edition 3.0 of IEC 61000-4-4 "improves and clarifies simulator specifications, test criteria and test setups" and replaced the 2004 edition with its 2010 amendment.
Neither basic standard is itself listed under the EMC Directive. Presumption of conformity comes from the generic and product standards that call them up (see below).
Surge: IEC 61000-4-5
Section titled “Surge: IEC 61000-4-5”The standard covers immunity to unidirectional surges caused by over-voltages from switching and lightning transients. It is not intended to test insulation withstand to high-voltage stress, and direct lightning strikes are out of scope.
Test levels (Table 1)
Section titled “Test levels (Table 1)”| Level | Line-to-line, open-circuit voltage | Line-to-ground, open-circuit voltage |
|---|---|---|
| 1 | Not applicable | 0.5 kV |
| 2 | 0.5 kV | 1 kV |
| 3 | 1 kV | 2 kV |
| 4 | 2 kV | 4 kV |
| X | Special | Special |
"X" can be any level, above, below or in between, and is set by the equipment specification. The test must be applied at all levels in Table 1 up to and including the specified level, because protection components have non-linear current-voltage characteristics. For symmetrical interconnection lines the test can be applied to several lines simultaneously with respect to ground.
Levels are not "classes". Annex B separately describes installation classes 0 to 5 (from a well-protected environment, often a special room, up to equipment connected to communication cables and overhead power lines in a non-densely populated area) and gives example level tables per class, which the standard says are for illustration only and are not a recommendation or requirement.
The two generators
Section titled “The two generators”| Parameter | 1.2/50 µs combination wave generator | 10/700 µs combination wave generator (Annex A) |
|---|---|---|
| Used for | All ports except the case on the right | Ports intended for outdoor symmetrical communication lines (PSTN, xDSL), typically longer than 300 m |
| Open-circuit voltage front time / duration | 1.2 µs ±30 % / 50 µs ±20 % | 10 µs ±30 % / 700 µs ±20 % |
| Short-circuit current front time / duration | 8 µs ±20 % / 20 µs ±20 % | 5 µs ±20 % / 320 µs ±20 % |
| Effective output impedance (peak voltage / peak current) | 2 Ω | 40 Ω (typically internal 15 Ω and 25 Ω) |
| Repetition rate | 1 per minute or faster | 1 per minute or faster |
| Phase shifting | 0° to 360° relative to the AC line, ±10° | Not applicable |
At the generator output the 1.2/50 µs generator delivers 0.25 kA at 0.5 kV, 0.5 kA at 1 kV, 1 kA at 2 kV and 2 kA at 4 kV (Table 3, ±10 %). The waveforms are specified at the point where they are applied to the EUT, so for AC or DC power ports they are verified at the output of the coupling/decoupling network (CDN), not at the generator.
For outdoor telecom ports, Annex A asks for testing with the intended primary protection so that coordination between primary and secondary protection can be verified, and refers to ITU-T K.44. It gives as examples a low level (0.5 kV or 1 kV) with only the secondary protection to evaluate equipment immunity, and a higher level (2 kV or 4 kV) with primary protection to evaluate system immunity.
Coupling, per port type
Section titled “Coupling, per port type”| Port | Coupling defined in the standard |
|---|---|
| AC/DC power, line-to-line | 18 µF capacitor, 2 Ω generator impedance |
| AC/DC power, line-to-ground | 9 µF capacitor plus 10 Ω resistor |
| Unshielded unsymmetrical interconnection lines | Line-to-ground and line-to-line through a coupling device, with a 40 Ω coupling resistor |
| Unshielded symmetrical lines (twisted pairs) | Always common mode, all lines to ground; coupling resistors on each line chosen so that their parallel value is 40 Ω (for example 4 × 160 Ω on a four-line port), up to 8 lines/4 pairs per CDN |
| Shielded lines, shield grounded at both ends | Surge applied to the shield (or the EUT enclosure), 2 Ω source with the 18 µF capacitor; cable to the auxiliary equipment 20 m preferred, or the shortest length over 10 m |
| Shielded lines, shield grounded at one end | Treated as unshielded lines; no surge on the shield |
Other setup rules that test plans regularly miss: the power cord or interconnection line between the EUT and the CDN must not exceed 2 m unless otherwise specified; no line-to-ground surges are applied to double-insulated products without a dedicated earth terminal; no test is required for shielded cables of 10 m or less according to the manufacturer specification; and on high-speed lines no surge is applied when normal functioning cannot be achieved because of the CDN. With gas arrestors as coupling devices, levels below their ignition point (about 300 V for a 90 V rated arrestor) cannot be specified.
Number of impulses and timing (clause 8.3)
Section titled “Number of impulses and timing (clause 8.3)”| Port | Impulses per coupling path (unless the relevant standard says otherwise) |
|---|---|
| DC power ports and interconnection lines | 5 positive and 5 negative |
| AC power ports | 5 positive and 5 negative at each of 0°, 90°, 180° and 270° (40 impulses) |
| AC coupling path without mains voltage (for example N to PE in TN-S) | 5 positive and 5 negative, no synchronisation |
- Time between impulses: one minute or less. If a test at a faster rate fails and a test at one per minute passes, the one-per-minute test prevails.
- Three-phase systems: the phase angle is taken from the voltage between the lines under test (for example L2 to L3).
- Line-to-ground: lines are tested individually in sequence unless otherwise specified.
- Low-voltage DC ports (≤ 60 V): surges are not applied when isolated secondary circuits are not subject to transient over-voltages (reliably grounded, capacitively filtered, ripple below 10 % of the DC component).
- Product committees may select different phase angles and increase or reduce the number of surges per phase.
Since all lower levels must also be tested, a single-phase AC port tested to level 3 line-to-ground runs the 40-impulse sequence at level 1 and level 2 before level 3, on each coupling path.
EFT/burst: IEC 61000-4-4
Section titled “EFT/burst: IEC 61000-4-4”The test applies bursts of fast transients to power, signal, control and earth ports. The standard describes it as significant for its high amplitude, short rise time, high repetition frequency and low energy, and as representative of switching transients such as interruption of inductive loads and relay contact bounce.
Test levels (Table 1)
Section titled “Test levels (Table 1)”| Level | Power ports and earth port (PE) | Signal and control ports | Repetition frequency |
|---|---|---|---|
| 1 | 0.5 kV | 0.25 kV | 5 or 100 kHz |
| 2 | 1 kV | 0.5 kV | 5 or 100 kHz |
| 3 | 2 kV | 1 kV | 5 or 100 kHz |
| 4 | 4 kV | 2 kV | 5 or 100 kHz |
| X | Special | Special | Special |
The note under the table states that 5 kHz is traditional, 100 kHz is closer to reality, and product committees decide which frequency is relevant. The same note was already in the 2004 edition. Annex B describes level 1 as a well-protected environment, level 2 as protected, level 3 as typical industrial and level 4 as severe industrial.
Generator and burst (clause 6.2)
Section titled “Generator and burst (clause 6.2)”| Parameter | Requirement |
|---|---|
| Effective output impedance | 50 Ω |
| Rise time into 50 Ω / 1 000 Ω | 5 ns ±1.5 ns / 5 ns ±1.5 ns |
| Pulse width into 50 Ω | 50 ns ±15 ns |
| Pulse width into 1 000 Ω | 50 ns, tolerance -15 ns to +100 ns |
| Burst duration | 15 ms ±3 ms at 5 kHz, 0.75 ms ±0.15 ms at 100 kHz |
| Burst period | 300 ms ±60 ms |
| Relation to AC mains | Asynchronous |
| DC blocking capacitor | 10 nF ±2 nF |
| Output range | At least 0.24 kV to 3.8 kV into 1 000 Ω, 0.125 kV to 2 kV into 50 Ω |
Both repetition frequencies give 75 pulses per burst (15 ms at 5 kHz, 0.75 ms at 100 kHz). Annex A explains that 0.75 ms was chosen as the reference duration at 100 kHz for that reason.
Coupling and setup (clause 7)
Section titled “Coupling and setup (clause 7)”- Power ports: direct coupling through a coupling/decoupling network with 33 nF coupling capacitors is the preferred method. Without a suitable CDN (for example above 100 A), direct injection through 33 nF ±6.6 nF capacitors is preferred, then the capacitive clamp.
- Signal and control ports: the capacitive coupling clamp, with the cable in the centre of the clamp. The clamp sits on the ground reference plane, which extends at least 0.1 m beyond it; the generator is connected at the end nearest the EUT.
- Earth terminal: the test point is the protective earth terminal; without a CDN, injection through a 33 nF capacitor.
- Distances: table-top EUT 0.1 m above the ground reference plane on an insulating support; floor-standing EUT on a 0.1 m support. Distance between coupling device and EUT 0.5 m (-0/+0.1 m) for table-top and 1.0 m ±0.1 m for floor-standing equipment, unless the product standard says otherwise. Excess cable length is bundled 0.1 m above the plane, on the auxiliary equipment side when the clamp is used.
- Duration: both polarities are mandatory, and the duration per port is never less than 1 minute.
The 2004 edition gave a typical clamp coupling capacitance of 100 pF to 1 000 pF. The 2012 edition replaced that with fixed plate dimensions (lower plate 1 000 mm ±50 mm long, 140 mm ±7 mm wide, 100 mm ±5 mm high) and a calibration with a transducer plate, noting that the actual coupling capacitance depends on the cable.
Performance criteria: who sets them
Section titled “Performance criteria: who sets them”Both methods end with the same recommended classification of results: (a) normal performance; (b) temporary loss of function or degradation that ceases after the disturbance, without operator intervention; (c) temporary loss or degradation that needs operator intervention; (d) loss not recoverable because of damage to hardware or software, or loss of data. IEC 61000-4-5 adds that equipment shall not become dangerous or unsafe as a result of the tests. The acceptance criterion comes from the generic or product standard.
The EU-cited generic standards define three criteria:
| Criterion | EN 61000-6-1:2007 and EN 61000-6-2:2005 |
|---|---|
| A | Operates as intended during and after the test, no degradation below the performance level specified by the manufacturer |
| B | Operates as intended after the test; degradation is allowed during the test, but no change of actual operating state or stored data |
| C | Temporary loss of function allowed, provided it is self-recoverable or can be restored by the operation of the controls |
Levels required by the EU-cited generic standards
Section titled “Levels required by the EU-cited generic standards”Under Directive 2014/30/EU, the generic immunity standards that give presumption of conformity are EN 61000-6-1:2007 (identical to IEC 61000-6-1:2005) and EN 61000-6-2:2005 with AC:2005 (IEC 61000-6-2:2005), both cited in the Commission communication published in the OJEU C 246 of 13 July 2018. Their surge and burst rows read:
| Port | Test | EN 61000-6-1 (residential, commercial, light industrial) | EN 61000-6-2 (industrial) | Criterion |
|---|---|---|---|---|
| AC power | Surge 1.2/50 µs | 2 kV line-to-earth, 1 kV line-to-line | 2 kV line-to-earth, 1 kV line-to-line | B |
| AC power | Burst 5/50 ns, 5 kHz | 1 kV | 2 kV | B |
| DC power (input) | Surge 1.2/50 µs | 0.5 kV line-to-earth, 0.5 kV line-to-line | 0.5 kV line-to-earth, 0.5 kV line-to-line | B |
| DC power | Burst 5/50 ns, 5 kHz | 0.5 kV | 2 kV | B |
| Signal | Burst 5/50 ns, 5 kHz, capacitive clamp | 0.5 kV, cables that may exceed 3 m | 1 kV, cables that may exceed 3 m | B |
| Signal | Surge 1.2/50 µs | No surge test | 1 kV line-to-earth, cables that may exceed 30 m | B |
The DC rows carry footnotes: they do not apply to input ports for a battery that must be removed or disconnected for recharging; a product powered by an AC-DC adaptor is tested on the AC input of that adaptor; DC ports not intended for a DC distribution network are treated as signal ports; and the DC burst test applies to input ports intended to be connected permanently to cables longer than 3 m. Both generic standards use 5 kHz, not 100 kHz.
For multimedia equipment, the EMC list cites EN 55035:2017 with A11:2020 (added by Decision (EU) 2021/455, consolidated in Decision 2019/1326). EN 55024:2010 left the list on 16 September 2022. EN 55035 is based on CISPR 35:2016 and has its own surge and burst tables per port type.
Surge, burst and ESD compared
Section titled “Surge, burst and ESD compared”| Test | Basic standard | Waveform | Phenomenon in the standard | EN 61000-6-1 level |
|---|---|---|---|---|
| ESD | IEC 61000-4-2 | Contact and air discharge | Electrostatic discharge (ESD) | 4 kV contact, 8 kV air (enclosure) |
| EFT/burst | IEC 61000-4-4 | 5/50 ns pulses in bursts | Switching transients, inductive loads, relay contact bounce | 1 kV on AC power |
| Surge | IEC 61000-4-5 | 1.2/50 µs voltage, 8/20 µs current | Switching and lightning over-voltages | 2 kV line-to-earth, 1 kV line-to-line on AC power |
See RED tests for EMC tests under the RED directive and CE tests for EMC Directive 2014/30/EU.
Road vehicles: ISO 7637-2, not IEC 61000-4-5
Section titled “Road vehicles: ISO 7637-2, not IEC 61000-4-5”On-board 12 V and 24 V supply lines of road vehicles are covered by ISO 7637-2, whose current edition dates from 2011, with its own pulse set (pulses 1, 2a, 2b, 3a and 3b). Load dump was a single pulse in ISO 7637-2:2004; it moved to ISO 16750-2, which requires 10 pulses at 1 minute intervals (secondary source: Vishay application article). A pass at a given IEC 61000-4-5 level says nothing about ISO 7637-2 performance: the waveforms and source impedances differ. For type approval see UN R10 (ECE R10).
Claims the texts contradict
Section titled “Claims the texts contradict”| Common claim (including on earlier versions of this page) | What the text says |
|---|---|
| Surge pulses need at least one minute between them | IEC 61000-4-5 clause 8.3: "1 min or less"; one per minute prevails only if a faster rate fails and one per minute passes |
| Surge levels are "Class 1 to 4" with environments such as "residential = Class 3" | Table 1 has levels 1 to 4 and X; installation classes 0 to 5 are a separate, informative Annex B scale |
| The surge is applied only at the target level | All lower levels in Table 1 up to and including the selected level shall be tested |
| A 12 Ω source applies to "high-impedance signal ports" | 10 Ω plus 9 µF is the line-to-ground coupling on power ports; unsymmetrical interconnection lines use 40 Ω coupling |
| Short symmetrical signal ports use a 42 Ω CDN "type S" | Symmetrical lines are coupled in common mode with resistors whose parallel value is 40 Ω |
| The 10/700 µs wave comes from ITU-T K.20 and K.21 | Annex A of IEC 61000-4-5 specifies the generator itself and refers to ITU-T K.44 for primary protection |
| EN 61000-6-1 requires 1 kV / 0.5 kV surge on AC mains | EN 61000-6-1:2007 Table 4: 2 kV line-to-earth, 1 kV line-to-line |
| EN 61000-6-1 has a 0.5 kV surge on signal ports | EN 61000-6-1 Table 2 has no surge row; EN 61000-6-2 has 1 kV line-to-earth for cables that may exceed 30 m |
| The 2012 edition of IEC 61000-4-4 introduced the 100 kHz option | The 2004 edition already listed 5 or 100 kHz, with the same note |
| 100 kHz is the preferred frequency for modern tests | The standard leaves the choice to product committees; EN 61000-6-1 and 6-2 specify 5 kHz |
| The burst clamp provides 50 pF to 200 pF and sits 0.1 m above the plane | The 2012 edition sets no capacitance value and places the clamp on the ground reference plane; the EUT and cables are 0.1 m above it |
| EFT level 3 is "moderate industrial, residential" | Annex B of IEC 61000-4-4 calls level 3 "typical industrial environment" |
| Criterion B tolerates temporary data loss | EN 61000-6-1 and 6-2: no change of actual operating state or stored data under criterion B |
| Every port with a cable leaving the enclosure is surge tested | In EN 61000-6-2, signal port surges apply only to cables that may exceed 30 m; EN 61000-6-1 has none; IEC 61000-4-5 exempts shielded cables of 10 m or less |
| EN 55024 is still an alternative for IT equipment | EN 55024:2010 left the EMC list on 16 September 2022 |
| ISO 7637-2 includes load dump pulses 5a/5b and starter pulse 4 | The 2011 edition covers pulses 1, 2a, 2b, 3a and 3b; load dump is in ISO 16750-2 |
Pitfalls in test plans
Section titled “Pitfalls in test plans”- Wrong surge generator for the port. Ethernet and other LAN ports take the 1.2/50 µs generator; 10/700 µs is for outdoor symmetrical communication lines intended for widely dispersed systems.
- Waveform verified at the generator, not at the CDN output. For power ports the specified waveforms apply at the EUT port of the CDN.
- Skipped lower levels. IEC 61000-4-5 requires every lower level of Table 1.
- Missing phase angles. AC power surges are synchronised at 0°, 90°, 180° and 270° unless a product standard says otherwise; the generator must phase-shift over 0° to 360° within ±10°.
- Cable lengths and distances. 2 m maximum between EUT and surge CDN; 0.5 m or 1.0 m between burst coupling device and EUT; excess burst cable bundled 0.1 m above the plane.
- Incomplete report. Both standards require drawings or pictures of the setup, all cable types and lengths, the performance criterion and the rationale for the pass/fail decision.
Test reports are usually produced by a laboratory accredited to ISO/IEC 17025 for these methods; the accreditation scope shows which editions are covered.
Takeaways
Section titled “Takeaways”- Current editions: IEC 61000-4-5 edition 3.1 (2014 + AMD1:2017) and IEC 61000-4-4 edition 3.0 (2012).
- Surge: levels 1 to 4 run 0.5 to 4 kV line-to-ground; 2 Ω generator, 18 µF line-to-line, 9 µF + 10 Ω line-to-ground; 10/700 µs with 40 Ω only for outdoor telecom lines; ten impulses per path, forty on AC with phase angles; one minute or less between impulses.
- Burst: 5/50 ns into 50 Ω, 75 pulses per burst at 5 kHz or 100 kHz, one burst every 300 ms, at least 1 minute per polarity; 50 Ω source; 33 nF CDN or capacitive clamp.
- EU levels come from the generic or product standard: EN 61000-6-1:2007 and EN 61000-6-2:2005 on AC mains require 2 kV / 1 kV surge, with 1 kV or 2 kV burst at 5 kHz, criterion B.
- Criteria A, B, C belong to the generic and product standards, not to the test methods.
See also
Section titled “See also”- Voltage dips + interruptions (IEC 61000-4-11)
- Harmonics and flicker (IEC 61000-3-2 and 3-3): mains quality
- Radiated emissions EMC test: pre-scan and final scan
- HEMP and IEMI: IEC 61000-4-25 and hardened electronics
- ESD per IEC 61000-4-2: method and test levels
- IEC 61000-4-6: conducted RF immunity
- EMC Directive 2014/30/EU: scope, standards, modules
- Glossary for the terms used here (EUT, IEC)
Sources & references
- IEC 61000-4-5:2014+AMD1:2017 CSV (Edition 3.1, 4 August 2017), surge immunity test, IEC webstore.iec.ch/en/publication/61166
- IEC 61000-4-5:2014 (Edition 3.0, 15 May 2014), surge immunity test, changes against the 2005 edition, IEC webstore.iec.ch/publication/4223
- IEC 61000-4-4:2012 (Edition 3.0, 30 April 2012), electrical fast transient/burst immunity test, IEC webstore.iec.ch/publication/4222
- IS 14700 (Part 4/Sec 4):2008, identical to IEC 61000-4-4:2004 (Edition 2), full text, Bureau of Indian Standards (via Public.Resource.Org) law.resource.org/pub/in/bis/S04/is.14700.4.4.2008.pdf
- IS 14700 (Part 6/Sec 1):2008, identical to IEC 61000-6-1:2005, Tables 2 to 4, Bureau of Indian Standards (via Public.Resource.Org) law.resource.org/pub/in/bis/S04/is.14700.6.1.2008.pdf
- IS 14700 (Part 6/Sec 2):2008, identical to IEC 61000-6-2:2005, Tables 2 to 4, Bureau of Indian Standards (via Public.Resource.Org) law.resource.org/pub/in/bis/S04/is.14700.6.2.2008.pdf
- Commission communication under Directive 2014/30/EU, OJ C 246, 13 July 2018 (EN 61000-6-1:2007, EN 61000-6-2:2005), Publications Office of the European Union publications.europa.eu/resource/celex/52018XC0713%2802%29
- Commission Implementing Decision (EU) 2019/1326, harmonised standards for EMC, consolidated text of 10 June 2022, Publications Office of the European Union publications.europa.eu/resource/celex/02019D1326-20220610
- Harmonised standards for electromagnetic compatibility, decisions and summary list, European Commission single-market-economy.ec.europa.eu/single-market/goods/european-standards/harmonised-standards/electromagnetic-compatibility-emc_en
- CISPR 35:2016, electromagnetic compatibility of multimedia equipment, immunity requirements, IEC webstore.iec.ch/en/publication/25667
- ISO 7637-2:2011, road vehicles, electrical transient conduction along supply lines only, ISO www.iso.org/standard/50925.html
- Load dump protection: old vs. new ISO standards (secondary source, Vishay application article), Vishay www.vishay.com/docs/49748/49748.pdf
- ITU-T Recommendation K.44, resistibility tests for telecommunication equipment exposed to over-voltages and overcurrents, ITU-T www.itu.int/rec/T-REC-K.44
Frequently asked questions
- What is the difference between the surge test (IEC 61000-4-5) and the EFT/burst test (IEC 61000-4-4)?
- IEC 61000-4-5 covers unidirectional surges caused by over-voltages from switching and lightning transients. Its combination wave generator delivers a 1.2/50 µs open-circuit voltage and an 8/20 µs short-circuit current, one impulse at a time, at most one minute apart. IEC 61000-4-4 covers repetitive fast transients from switching transients such as interruption of inductive loads and relay contact bounce: 5/50 ns pulses repeated at 5 kHz or 100 kHz in bursts of 15 ms or 0.75 ms, one burst every 300 ms, for at least one minute per port and polarity.
- Which surge and burst levels apply to a product sold in the EU?
- The test methods set no mandatory level. Levels come from the product or generic standard. The generic standards cited under the EMC Directive are EN 61000-6-1:2007 and EN 61000-6-2:2005. On AC power ports both require surges of 2 kV line-to-earth and 1 kV line-to-line; burst is 1 kV in the residential, commercial and light-industrial standard and 2 kV in the industrial one, at 5 kHz, all at criterion B. Multimedia equipment uses EN 55035:2017+A11:2020 instead.
- Are the surge levels "Class 1 to 4"?
- No. IEC 61000-4-5 Table 1 has test levels 1 to 4 and X. Level 1 is 0.5 kV line-to-ground only; levels 2, 3 and 4 are 0.5, 1 and 2 kV line-to-line and 1, 2 and 4 kV line-to-ground. Installation classes 0 to 5 are a different, informative scale in Annex B, whose example tables the standard says are for illustration only. All lower levels up to and including the selected level must be tested.
- How many surge impulses are applied, and how fast?
- Unless the relevant standard says otherwise, five positive and five negative impulses per coupling path on DC power ports and interconnection lines, and five positive and five negative impulses at each of 0°, 90°, 180° and 270° on AC power ports. The time between impulses is one minute or less. If a test at a faster rate fails and a test at one per minute passes, the one-per-minute result prevails.
- When is the 10/700 µs surge used instead of 1.2/50 µs?
- Only for ports intended to connect to outdoor symmetrical communication lines that interconnect widely dispersed systems, such as the public switched telephone network or xDSL, typically longer than 300 m. Annex A of IEC 61000-4-5 specifies that generator: 10/700 µs open-circuit voltage, 5/320 µs short-circuit current, 40 Ω effective output impedance. Ethernet and other local area network ports use the 1.2/50 µs generator.
- What does the capacitive coupling clamp of IEC 61000-4-4 look like?
- It is placed on the ground reference plane, with a lower coupling plate of 1 000 mm long, 140 mm wide and 100 mm high (with tolerances). It is used for signal and control lines, and on power ports only when a coupling/decoupling network cannot be used. The 2012 edition gives no fixed coupling capacitance: it states that the capacitance depends on cable diameter, material and shielding, and the clamp is calibrated with a transducer plate.
- Where do performance criteria A, B and C come from?
- Not from the test methods. IEC 61000-4-4 and 4-5 only recommend a four-step classification of results (a to d). Generic and product standards define the acceptance criteria. In EN 61000-6-1 and 6-2, criterion B allows degradation during the test but no change of operating state or stored data, and criterion C allows temporary loss of function that is self-recoverable or restored by the controls.