1. Standard Title and Purpose
EN IEC 61000-4-29:2026
Electromagnetic compatibility (EMC) – Part 4-29: Testing and measurement techniques – Voltage dips, short interruptions and voltage variations on d.c. input power port immunity tests.
This standard is intended to evaluate the immunity of equipment with DC input power ports when subjected to the following DC power disturbances:
Test item | Description |
Voltage dips | A temporary reduction of the DC supply voltage, for example from 100% rated voltage to 70%, 40%, or lower. |
Short interruptions | A temporary interruption of the DC supply voltage, close to 0 V. |
Voltage variations | A gradual or temporary increase or decrease of DC voltage over a defined period, simulating battery operation, backup power switching, or DC network variation. |
2. Scope of Application
EN IEC 61000-4-29 applies to electrical and electronic equipment with a DC input power port, especially equipment powered by an external DC network or DC power distribution system.
Typical applicable products include:
Product / System | Applicable situation |
Industrial control equipment | 24 Vdc or 48 Vdc control power input |
Telecom and network equipment | -48 Vdc telecom power systems |
Data center DC-powered equipment | 380 Vdc, 400 Vdc, 800 Vdc, or other DC distribution systems |
Railway, vehicle, or power equipment | DC auxiliary power input |
Battery-powered or energy storage equipment | Battery switching, charge/discharge conditions, or backup power switching |
3. Difference from IEC 61000-4-11 and IEC 61000-4-34
Standard | Power type | Application |
IEC/EN 61000-4-11 | AC | Voltage dips, short interruptions, and voltage variations for AC equipment with input current up to 16 A per phase. |
IEC/EN 61000-4-34 | AC | Voltage dips, short interruptions, and voltage variations for AC equipment with input current greater than 16 A per phase. |
IEC/EN 61000-4-29 | DC | Voltage dips, short interruptions, and voltage variations for DC input power ports. |
In simple terms, IEC 61000-4-11 and IEC 61000-4-34 are used for AC power ports, while IEC 61000-4-29 is used for DC input power ports.
4. Main Changes Expected in the 2026 Edition
Compared with the 2000 edition, the 2026 edition is expected to be a technical revision. The main changes are summarized below:
Change item | Description | Practical impact |
Increased output voltage capability of the test generator | To address new DC network voltages | More relevant for high-voltage DC systems such as 380 Vdc, 400 Vdc, or 800 Vdc equipment |
Added tolerance for voltage variation duration | Clarifies the tolerance of test duration | Test settings and actual duration should be recorded in the report |
Current limitation during short interruptions under low impedance conditions | Prevents excessive current or short-circuit risk | Test equipment capability and EUT protection conditions need to be confirmed |
Clarification of test generator specifications and verification | Provides clearer requirements for generator performance and verification | Calibration or verification items may need to be reviewed |
Clarification of switching characteristics and inrush current verification load | Provides additional details regarding load conditions | The laboratory should confirm whether the verification load meets the new requirements |
Clarification of evaluation and test report requirements | Provides clearer requirements for result evaluation and reporting | The report should include test level, duration, operating mode, and performance criteria |
Addition of DC environment descriptions | Provides background information on DC networks | Useful for explaining DC system applications and test relevance |
5. Test Concept
This test is not a surge, EFT, or ripple test. It is intended to simulate DC power supply quality disturbances.
Typical causes include:
Phenomenon | Possible cause |
DC voltage dip | Large load startup, battery switching, or temporary DC bus voltage drop |
DC short interruption | Power source switching, protection device operation, or contact interruption |
DC voltage variation | Battery/rectifier switching, backup power transfer, or DC network voltage regulation |
The following parameters normally need to be defined during the test:
1. Rated DC input voltage, Un
2. Test level, such as a percentage of Un or 0% Un
3. Duration；
4. Number of repetitions and interval
5. EUT operation mode；
6. Performance criteria, such as Criteria A, B, or C, or the criteria specified by the product standard
6. Significance for 800 Vdc / HVDC Products
The 2026 edition is expected to address higher DC network voltages by increasing the output voltage capability of the test generator. This makes the standard more relevant to modern high-voltage DC systems, such as data center DC distribution, energy storage systems, power conversion equipment, and 800 Vdc architectures.
However, IEC 61000-4-29 is a basic EMC publication. It does not automatically mean that the test is mandatory for every product with a DC input. In practice, applicability should be determined based on the relevant product standard, product family standard, generic standard, or customer specification, such as EN IEC 61000-6-2, EN IEC 61000-6-4, EN 55011 / CISPR 11, EN 55032 / CISPR 32, or other dedicated product standards.
7. Brief Conclusion
EN IEC 61000-4-29:2026 is an EMC immunity test standard for voltage dips, short interruptions, and voltage variations on DC input power ports.
The key focus of the 2026 edition is to address new DC power distribution environments, especially higher-voltage DC systems. It also clarifies test generator capability, duration tolerance, current limitation during short interruptions, inrush current verification, result evaluation, and test report requirements.
For products using 24 Vdc, 48 Vdc, 380 Vdc, 400 Vdc, 800 Vdc, or other DC input power systems, this standard is highly relevant when DC power port immunity is required by the applicable product standard, generic EMC standard, or customer specification.
