IEC 61000-4-4 EFT/Burst for Medical Devices: Getting Through ±2 kV

Mains-powered medical electrical equipment usually faces the electrical fast transient/burst test (EFT/B, "burst" below) in EMC immunity testing. This article covers the IEC 61000-4-4 / GB/T 17626.4 waveform, levels and setup; the port levels and conditions in IEC 60601-1-2 and YY 9706.102 (where the ±2 kV on the mains port comes from); typical failures and fixes; pass/fail; and the accreditation SUNGO reports under.

Key points

• The test method is IEC 61000-4-4:2012 (Edition 3.0). EN 61000-4-4:2012 is based on it and GB/T 17626.4-2018 adopts it identically. The product standard decides which ports are tested and at which level.
• IEC 60601-1-2 Editions 4.0 and 4.1: a.c. power port ±2 kV at 100 kHz repetition frequency; d.c. power port ±2 kV at 100 kHz, only for ports intended to be connected permanently to cables longer than 3 m; signal input/output ports ±1 kV at 100 kHz, excluding those whose maximum cable length is less than 3 m; the patient coupling port (Table 7) has no burst test.
• YY 9706.102-2021 is a modified adoption of IEC 60601-1-2:2007: ±2 kV on power lines and ±1 kV on signal and interconnecting cables; signal/interconnecting cables specified as shorter than 3 m and all patient-coupled cables are not tested directly; the clause does not specify a repetition frequency. So port conditions and supply-voltage rules differ.
• A burst is a train of nanosecond pulses with high amplitude, fast rise and low energy. Typical failures in practice: resets, display corruption, communication dropouts and false alarms; fixes start with common-mode filtering, grounding and cable routing.
• Pass/fail goes back to the basic safety, essential performance and pass/fail criteria the manufacturer defined in advance.
• The standards in the scope table below are within the Hefei laboratory's IAS accreditation (TL-1119), listed as whole standards without year. Confirm with the laboratory which edition the IAS report will cite before the job is accepted.

Standards and scope

Test method: IEC 61000-4-4 / EN 61000-4-4 / GB/T 17626.4

According to the IEC abstract, IEC 61000-4-4 is a basic EMC publication on the immunity of electrical and electronic equipment to repetitive electrical fast transients on supply, signal, control and earth ports. Clause 1 lists what it defines: test voltage waveform, range of test levels, test equipment, its calibration and verification, test setups and test procedure. Edition 3.0 was published on 2012-04-30, replacing the 2004 edition and its amendment.

Clause 4 traces the phenomenon to switching transients such as interrupting inductive loads and relay contact bounce; what matters is high amplitude, short rise time, high repetition frequency and low energy.

• EN 61000-4-4:2012: the Estonian standards body (EVS) lists IEC 61000-4-4:2012 as its base document and also shows a draft, prEN IEC 61000-4-4:2026.
• New edition: as of 2026-10-22, the IEC webstore shows IEC 61000-4-4 Edition 4.0 under development (stage code CD, forecast publication date 2026-12-31). Check IEC and the European standards bodies for its status.
• GB/T 17626.4-2018: published 2018-06-07, implemented 2019-01-01, replaces the 2008 edition, identical adoption of IEC 61000-4-4:2012; reviewed on 2021-07-26 and confirmed as still valid.

Medical collateral standards: IEC 60601-1-2 and YY 9706.102 are different generations

IEC 60601-1-2 covers the basic safety and essential performance of ME equipment and ME systems in the presence of electromagnetic disturbances. Edition 4.0 was published on 2014-02-25 and consolidated Edition 4.1 (with Amendment 1:2020) on 2020-09-01; both cite IEC 61000-4-4:2012. Immunity test levels are in subclause 8.9, organised by port: Table 4 enclosure port, Table 5 input a.c. power port, Table 6 input d.c. power port, Table 7 patient coupling port, and Table 8 signal input/output parts port (retitled "SIP/SOP PORT" by Amendment 1). EN 60601-1-2:2015 and its A1:2021 are based on Edition 4.0 and Amendment 1 respectively.

YY 9706.102-2021 is a mandatory Chinese industry standard, published 2021-03-09 and implemented 2023-05-01, replacing YY 0505-2012; as of 2026-10-22, the SAMR national standards platform lists it as in force. Its cover and foreword state that it is a modified adoption of IEC 60601-1-2:2007, so it keeps the third-edition structure: the burst requirement sits in subclause 6.2.4 rather than in port tables, and it references GB/T 17626.4-2018.

Under subclause 1.3.2 of IEC 60601-1-2, a particular standard takes priority over the collateral standard, so check whether yours changes burst levels, ports or criteria.

The burst waveform

From the generator requirements in IEC 61000-4-4:2012, 6.2.2 (effective output impedance 50 Ω):

Per Annex A, a 0.75 ms burst at 100 kHz has 75 pulses. The note to Table 1 says 5 kHz is traditional, 100 kHz is closer to reality, and product committees decide which applies.

Test levels: the basic standard offers the menu, the medical standard picks by port

Preferred test levels from Table 1 of IEC 61000-4-4 (peak open-circuit output voltage); each level may use 5 kHz or 100 kHz:

Annex B links levels 1 to 4 to well-protected, protected, typical industrial and severe industrial environments; level X is for special situations to be analysed. Footnote a to Table 1 says level X is specified in the dedicated equipment specification.

For medical electrical equipment the collateral standard sets the level. The table below compares the two standards' burst requirements as written (in IEC 60601-1-2 the burst level is the same for the professional healthcare facility and home healthcare environments):

The ±2 kV / ±1 kV pair in both standards is level 3 of IEC 61000-4-4. Annex A of YY 9706.102-2021 explains that level 3 corresponds to environments with little isolation between power, control, signal and communication cables, which is sometimes the case in hospitals, and that it gives a larger safety margin than level 2.

Do not borrow cable conditions from other tests: the "less than 1 m excluded" footnote that Amendment 1 added to the conducted RF row of Table 8 does not apply to bursts.

Coupling and test setup

Coupling: CDN for power ports, capacitive clamp for signal ports

• Power ports: IEC 61000-4-4 prefers direct coupling through a coupling/decoupling network (CDN), calibrated in common mode (all lines at once against the ground reference plane); Tables 5 and 6 of IEC 60601-1-2 also require direct coupling. Without an earth terminal, the voltage goes to L and N only.
• Signal ports: use the capacitive coupling clamp with the cable in its centre and no galvanic connection to terminals or shields. The ground reference plane extends at least 0.1 m beyond the clamp on all sides, and the generator connects to the clamp end nearest the EUT.
• With a protective earth terminal, the enclosure test point is that terminal. Decoupling networks or common-mode absorption devices protect auxiliary equipment and the mains.

Layout: ground reference plane and insulating supports

• Ground reference plane: copper or aluminium at least 0.25 mm thick (other metals at least 0.65 mm), at least 0.8 m × 1 m, extending at least 0.1 m beyond the EUT on all sides and connected to protective earth.
• Floor-standing EUTs stand on an insulating support (0.1 ± 0.05) m thick, including non-conductive castors; table-top, wall-mounted, ceiling-mounted and built-in equipment is placed (0.1 ± 0.01) m above the plane.
• More than 0.5 m between the EUT and other conductive structures; cables lie on an insulating support 0.1 m above the plane.
• Coupling device to EUT: 0.5 m (−0/+0.1 m) for table-top and (1.0 ± 0.1) m for floor-standing equipment unless the product standard says otherwise; if another distance is used, record it in the report.
• The EUT is earthed per the manufacturer's installation specification, with no additional earthing connections.
• Under YY 9706.102-2021, patient-coupled cables stay connected and are arranged as in normal use, and patient coupling points are terminated with the RC element of GB/T 6113.102 (through the artificial hand where there is no conductive contact with the patient).

What the test plan must cover

Clause 8.3 of IEC 61000-4-4 requires a test plan stating the level, coupling mode, polarity (both are mandatory), duration per port (never less than 1 min unless the product committee decides otherwise), repetition frequency, ports, operating conditions and auxiliary equipment. Annex G of IEC 60601-1-2 gives test plan guidance.

Typical failures

The following is engineering experience, not standard text. Bursts carry low energy (IEC 61000-4-4, Clause 4), but their fast edges arrive in trains and usually enter as common-mode current through cables and stray capacitance; failures typically appear as temporary malfunctions:

• Reset or reboot via the reset pin, supply supervisor or a low-voltage rail.
• Display flicker, corrupted screens or garbled characters.
• Communication errors or dropouts on USB, serial, Ethernet or sensor buses.
• False alarms from reading spikes, or a missed alarm.
• Phantom key presses, changed settings, or brief fluctuations in therapy output.

Design fixes

Common engineering approaches for R&D teams; these are not test services within SUNGO's accreditation:

• Mains inlet: add or enlarge a common-mode choke with line-to-earth Y capacitors to return common-mode current to protective earth near the inlet. Y capacitors raise earth leakage current, so recheck the IEC 60601-1 leakage requirements.
• Filter mounting: close to the inlet, housing bonded to the chassis by a short, wide connection, input and output wiring kept apart.
• Grounding: short, wide, low-inductance bonds and a planned junction for protective earth, functional earth and shields, keeping disturbance current away from sensitive circuit references.
• Cables: terminate shields properly at the connector, add ferrite cores on longer cables, and separate internal power and signal wiring.
• Circuits and software: filter reset and critical inputs, decouple rails locally, add watchdogs, communication retries and input debouncing. Software must not hide a hazardous state; alarm-logic changes go back through risk analysis.

The FDA guidance "Electromagnetic Compatibility (EMC) of Medical Devices" (issued 2022-06-06) lists ferrite beads, filters, shielding and firmware or software changes as common modifications to pass EMC testing, and recommends describing them and stating whether results came before or after them. For locating the cause and scoping a retest, see EMC Failures: Locating the Cause, Fixing It, Scoping the Retest.

Burst versus surge

Both are supply-line transients. A burst (IEC 61000-4-4) is a train of nanosecond pulses: high frequency, low energy, applied in common mode. Surge (IEC 61000-4-5), per the IEC abstract, covers unidirectional surges caused by over-voltages from switching and lightning transients; the combination wave generator delivers a 1.2/50 μs open-circuit voltage and an 8/20 μs short-circuit current, a single microsecond-scale impulse. Burst fixes centre on common-mode filtering, grounding and routing; surge usually needs energy-absorbing protection components.

Pass/fail: back to basic safety and essential performance

Clause 9 of IEC 61000-4-4 gives a generic classification (normal performance; self-recovering temporary degradation; degradation needing operator intervention; unrecoverable loss from damage or lost data) as a guide for product standards and for manufacturer-purchaser agreements.

For medical electrical equipment that is not enough. IEC 60601-1-2 judges results against basic safety and essential performance; its Annex I covers identifying pass/fail criteria. The FDA guidance recommends quantitative, device-specific, observable criteria documented in the test plan before testing; "Performance Criterion A" is not specific enough. For transients, providing the specified performance after the disturbance might be acceptable, with a recovery time specified on the basis of risk analysis.

So whether "reset and recovered by itself" passes depends on the predefined essential performance and criteria. For assessing device performance under EM disturbances, IEC TS 60601-4-2:2024 gives guidance, and its Annex D gives example criteria for a radiological table system and ultrasonic diagnostic equipment. The scope lists IEC TS 60601-4-2, without a year, within the Hefei laboratory's IAS accreditation (TL-1119); confirm the edition for the report with the laboratory before acceptance.

Accreditation scope table

Each row is an entry in the IAS scope (TL-1119) of Hefei SUNGO Medical Technology Co., Ltd., listed as the whole standard with no clauses, limitations or year. Titles are quoted as listed.

Where SUNGO does this and under which accreditation

• Testing is done by the laboratory of Hefei SUNGO Medical Technology Co., Ltd. in Zipeng Town, Feixi County, Hefei. All items above are within the Hefei laboratory's IAS accreditation (TL-1119).
• Shanghai SUNGO Medical Technology Co., Ltd. (laboratory at No. 958 Kangqiao East Road, Pudong, Shanghai) is a separate legal entity; its accreditation scope does not include the EMC standards in this article.
• The scope gives no years, so confirm with the laboratory before acceptance whether the IAS report cites IEC 60601-1-2 Edition 4.0 or 4.1, EN 60601-1-2, or YY 9706.102-2021.
• Surge (IEC 61000-4-5, EN 61000-4-5, GB/T 17626.5) is also within the Hefei laboratory's IAS accreditation (TL-1119) and can share the test plan.
• Regulatory acceptance depends on the target market and must be confirmed by the manufacturer; this article makes no promise about it.

Preparing for the test

• Product information: model, intended use, environment (professional healthcare, home healthcare or special), any particular standard, and the intended collateral standard edition.
• Port and cable list: a.c./d.c. power ports, SIP/SOPs and patient-coupled cables; for each cable, its type, shielding and the manufacturer's maximum length. The 3 m line decides whether some ports and cables are tested directly.
• Supply data: rated voltage and frequency, and whether the input is multi-voltage or auto-ranging. Under YY 9706.102-2021 such equipment is tested at the minimum and maximum rated input voltage, and equipment with an internal backup battery must be shown to continue operating from mains after the test.
• Installation and earthing: protective earth or not, table-top or floor-standing, installation instructions.
• Essential performance and criteria: what is monitored, how, and acceptable deviation and recovery time, in the test plan beforehand.
• Operating modes and auxiliary equipment: worst-case mode, patient simulators, loads, host software, and supplied cables and accessories.
• Samples: the final product or equivalent units; agree quantity and spares with the laboratory at acceptance.

FAQ

5 kHz or 100 kHz?

Tables 5, 6 and 8 of IEC 60601-1-2 Editions 4.0/4.1 all specify 100 kHz. Subclause 6.2.4 of YY 9706.102-2021 does not specify a repetition frequency; when testing to it, state the frequency in the test plan and confirm it with the laboratory.

How is the burst applied if there is no protective earth terminal?

Under 7.3.2.2 of IEC 61000-4-4, the test voltage goes to L and N only. The device is still installed per the manufacturer's instructions, without extra earthing.

Do signal cables shorter than 3 m have to be tested?

Table 8 of IEC 60601-1-2 Editions 4.0/4.1 excludes SIP/SOPs whose maximum cable length is less than 3 m. YY 9706.102-2021 does not test such cables directly, but its Annex A says that if disturbance coupled from the tested cables causes non-compliance, the device still fails. State maximum cable lengths in the instructions for use and test plan.

The device reset and recovered by itself. Is that a pass?

It depends on the criteria defined in advance. Recovery within a recovery time justified by risk analysis may pass; if the reset interrupted therapy, lost an alarm or changed a setting, judge it against essential performance and the risk analysis.

To arrange burst testing or a full medical EMC programme, prepare the items under "Preparing for the test" and send them via our contact page; see also our EMC testing services. The laboratory will confirm editions and the test plan with you first.