1. Conducted & Radiated Emissions – EN 55032 / CISPR Standards

Emissions tests answer a simple question: how much noise does your equipment send back into the mains and out into the air? For many power electronics products, the relevant standards are EN 55032 or CISPR 11/32 and related emissions standards used for industrial, IT or multimedia equipment.

In a typical conducted emissions test, an AC or DC powered device is connected to a LISN and the noise it sends back towards the mains is measured over a defined frequency range. Radiated emissions tests measure electric and magnetic field strength at a distance, usually in an anechoic chamber or on an open test site.

For power supplies, DC power systems and control cabinets this means:

• Switching edges in converters and inverters create narrow-band peaks at the switching frequency and its harmonics.
• Cables, backplanes and enclosures act as antennas, determining how much of that noise escapes as radiated emissions.
• Filters, layouts and grounding strategies are key tools to keep emissions within the limits of the chosen standard.

In the TPS lab, emissions measurements are a core part of emc testing for power electronics. During pre-compliance, we often run quick scans with several setups to find worst-case conditions before you invest in a full certified test campaign.

2. Harmonics & Flicker – EN 61000-3-2 / EN 61000-3-3

Harmonics and flicker standards focus on how your equipment draws power from the grid, rather than on the high-frequency noise it produces. EN 61000-3-2 covers harmonic currents, while EN 61000-3-3 addresses voltage changes and flicker that could disturb other loads on the same network.

Power-factor-corrected AC-DC supplies, chargers and other high-power equipment are especially relevant here. Poorly controlled input stages can:

• Inject excessive harmonic currents into the mains.
• Cause visible flicker or voltage variations when loads change quickly.
• Expose weaknesses in control algorithms at low or high mains voltages.

While not every project needs full harmonics and flicker testing during pre-compliance, these standards are important to keep in mind for higher power designs or when your customer explicitly calls them out in specifications.

3. ESD – IEC/EN 61000-4-2

IEC/EN 61000-4-2 defines electrostatic discharge (ESD) tests. These simulate fast, high-voltage discharges that occur when people or objects touch your equipment. Even if your power electronics live inside a cabinet, ESD can still enter through connectors, front panels and external wiring.

During ESD tests, a generator applies contact and air discharges to defined points on the enclosure and to interface ports. For power supplies, control boards and cabinets, typical ESD issues include:

• Spontaneous resets of PLCs, controllers or communication modules.
• Temporary loss of measurement accuracy or mis-triggered inputs.
• Permanent damage to sensitive interfaces if protection is insufficient.

In pre-compliance sessions, TPS focuses on realistic discharge points and monitors system behaviour closely. Improving ESD robustness often combines better protection devices, controlled discharge paths and clear shielding and grounding concepts.

4. EFT / Burst – IEC/EN 61000-4-4

IEC/EN 61000-4-4 defines Electrical Fast Transient (EFT) or burst tests. These simulate bursts of fast, repetitive pulses coupled onto power and signal lines, similar to what happens when contactors, relays or other switching devices operate on the same network.

For power electronics, EFT tests stress:

• Mains inputs of AC-DC power supplies and battery chargers.
• DC distribution rails in DC power systems.
• I/O lines on control and communication boards in industrial control panels.

Common symptoms include momentary drops in DC voltage, microcontroller resets and communication glitches. Pre-compliance testing gives you time to adjust filters, add decoupling and improve reset strategies before formal tests.

5. Surge – IEC/EN 61000-4-5

IEC/EN 61000-4-5 covers surge immunity. Surges are slower, higher-energy pulses than EFT bursts and represent disturbances such as lightning strikes or switching events on power lines. They can cause insulation stress and destructive overvoltages if not managed properly.

For power supplies, DC power systems and OEM modules, surge tests focus on:

• AC mains and DC power inputs, where surge energy is highest.
• Lines that leave and enter cabinets, such as long sensor and communication cables.
• Coordination of surge protection devices, fuses and clearances.

In EMC pre-compliance, TPS helps you explore different protection strategies and grounding options. The aim is to find a design that survives expected surge levels without damage and continues functioning acceptably, long before you run formal surge tests at a certification house.

6. Conducted RF Immunity – IEC/EN 61000-4-6

IEC/EN 61000-4-6 defines conducted RF immunity tests, where a controlled RF signal is injected onto cables connected to your product. This simulates nearby radio transmitters and other RF sources that couple into wiring.

In power electronics and industrial systems, conducted RF tests are particularly relevant for:

• Long signal and communication cables entering and leaving control cabinets.
• Analogue measurement lines that could pick up RF and show false readings.
• Digital communication links that might lose data or experience timeouts.

During pre-compliance testing, we monitor the behaviour of sensitive circuits while RF is injected, then adjust shielding, filtering and grounding to improve immunity. This is especially important when power electronics and control electronics share the same wiring routes.

7. Magnetic Fields at Mains Frequency – IEC/EN 61000-4-8

IEC/EN 61000-4-8 covers immunity to magnetic fields at mains frequency, typically 50 Hz or 60 Hz. These fields arise near transformers, busbars, large inductors and heavy current paths.

For power electronics and control cabinets, magnetic field immunity matters when:

• Sensitive analogue sensors or low-level signal circuits are located close to high-current conductors.
• Magnetic components saturate or behave non-linearly in strong external fields.
• Physical layouts place control boards near mains transformers or large chokes.

While not always the dominant issue in every project, magnetic field immunity is worth considering in compact systems where power density is high and space between power and control circuits is limited.

8. Voltage Dips, Short Interruptions & Variations – IEC/EN 61000-4-11

IEC/EN 61000-4-11 defines tests for voltage dips, short interruptions and voltage variations on AC supply lines. For DC-powered equipment, similar considerations apply when the DC bus experiences sudden changes in voltage.

Power supplies, battery chargers and DC power systems must show that:

• They either ride through short dips without unacceptable behaviour, or recover in a controlled way.
• Control electronics and communication remain predictable during and after disturbances.
• Protection and restart strategies avoid unsafe or confusing operating states.

In the TPS lab, these tests often intersect with functional safety and system design discussions. We help you see how your design behaves during supply variations and where simple changes can improve resilience.

Putting the EMC Test Standards Together in a Project

For a real product—whether it is a DIN-rail power system, a DC power system, a control cabinet or OEM electronics—these EMC test standards do not stand alone. They form a package of requirements that must be interpreted in the context of your markets and applications.

In practice, that means:

• Choosing the right emissions and immunity standards for your product category and environment.
• Defining realistic test setups that reflect how your equipment will be installed and used.
• Using EMC pre-compliance testing to explore worst cases and debug problems before certification.

The case studies on typical power devices we test show how the same EMC standards apply differently to DIN-rail systems, AC-DC and DC-DC supplies, battery chargers, control boards and OEM modules.

If you are planning EMC testing for a new project and want to understand how these standards apply to your design, the TPS team can help you turn standard numbers into a concrete EMC plan.

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