IEC 61000, CISPR, GB/T 17626 — The EMC Standards System Explained in One Article

Core takeaway: The three EMC standards systems divide the work clearly - CISPR governs emissions (EMI), IEC 61000 governs immunity (EMS) + generic requirements + harmonics, and GB/T 17626 is the Chinese identical adoption of IEC 61000-4. Standards are tiered: product standards > generic standards > basic standards. If a product standard exists, use it; only fall back to generic standards when none exists. Step 1 of selecting a standard is "determine the product category"; step 2 is finding the corresponding product standard.

1. System Overview

The EMC standards system looks complex, but it is really just three blocks:

The division of labor in one sentence:

CISPR: measures "how much noise you make" (emissions);

IEC 61000: measures "how well you withstand the noise" (immunity) + generic requirements + harmonics;

GB/T 17626: the Chinese version of IEC 61000-4, used domestically.

2. CISPR - Emission Standards

2.1 What is CISPR

CISPR = Comité International Spécial des Perturbations Radioélectriques (International Special Committee on Radio Interference), under the IEC.

Core responsibility: developing electromagnetic emission (EMI) standards - your equipment must not interfere with broadcasting, TV, or communications.

2.2 Major CISPR standards

Note:

CISPR 22 (information technology equipment, ITE) has been replaced by CISPR 32 - stop using the old standard;

CISPR 32 covers both CISPR 13 (audio/video) and CISPR 22 (ITE), unified as "multimedia equipment".

2.3 What CISPR tests

Conducted emission (CE): 150 kHz – 30 MHz (mains port);

Radiated emission (RE): 30 MHz – 1 GHz (or 6 GHz);

Limits are graded by product category and environment (Class A industrial / Class B residential).

3. IEC 61000 - Immunity + Generic + Harmonics

3.1 What is IEC 61000

IEC 61000 is a large series divided into multiple parts:

3.2 IEC 61000-4: immunity test methods (core)

This is the part engineers deal with most. Each -4-x corresponds to one immunity test:

3.3 IEC 61000-3: emission limits (harmonics/flicker)

3.4 IEC 61000-6: generic standards

When no product standard exists, use the generic standards:

4. GB/T 17626 - Chinese National Standards

4.1 What is GB/T 17626

The GB/T 17626 series is the identical adoption of the IEC 61000-4 series and is China's national standard for EMC immunity testing.

4.2 Correspondence

Other commonly used domestic standards:

EMC standards are tiered by priority:

Rule: use the product standard if one exists; otherwise use the generic standard; basic standards only define test methods.

5. Standards for common products

6. Immunity levels quick reference

Immunity tests usually have severity levels - the higher the level, the more severe:

Note: the specific level is set by the product standard - you cannot choose it freely.

7. Domestic certification

7.1 CCC certification (mandatory)

China Compulsory Certification - EMC-related products must pass it.

ITE category: GB 9254 (emission) + GB/T 17626 (immunity) + GB 17625 (harmonics);

Test standards are GB/T (recommended), but CCC makes passing them mandatory.

7.2 Other certifications

CQC voluntary certification: not mandatory but frequently requested;

Automotive: GB/T 18655, GB/T 21437;

Medical: YY 0505 (identical to IEC 60601-1-2).

8. How to choose a standard (three steps)

Step 1: Determine the product category

Which category is your product? (multimedia, appliance, lighting, industrial, medical, automotive…)

Step 2: Find the product standard

Check whether a product standard exists (CISPR xx or IEC xxxx):

Yes → use the product standard (it defines the emission limits and immunity levels);

No → use the generic standard IEC 61000-6.

Step 3: Test to the standard

Emission: test per CISPR / 61000-3;

Immunity: test per the 61000-4 series, with levels set by the product standard;

In China: use the corresponding GB/T standards.

9. Ten common mistakes

1. Wrong standard choice: using a generic standard instead of a product standard;

2. Using outdated standards: still using CISPR 22, which has been replaced by CISPR 32;

3. Picking levels arbitrarily: immunity levels follow the product standard - stricter is not automatically better;

4. Looking only at emission and not immunity: EMC works in both directions;

5. Not knowing that GB/T 17626 = IEC 61000-4;

6. Confusing the roles of CISPR and IEC 61000: CISPR = emission, 61000 = immunity;

7. Ignoring the harmonics standard (61000-3-2): often required for equipment >75 W;

8. Not distinguishing Class A/B: residential uses Class B (stricter), industrial uses Class A;

9. Looking only at IEC and not GB: domestic certification requires GB standards;

10. Not knowing that product standards take priority over generic standards.

10. Quick-reference tables

Division of labor among the three systems

Product → standard

Immunity items

11. The one-sentence takeaway

The three EMC standards systems divide the work clearly: CISPR governs emissions (how loud you are to others), IEC 61000 governs immunity (how well you withstand the noise) + generic requirements + harmonics, and GB/T 17626 is the Chinese version of IEC 61000-4. Standards are tiered: product > generic > basic - use product standards whenever they exist. Three steps: determine the product category → find the product standard (otherwise generic IEC 61000-6) → test to the standard. Remember the key replacements: CISPR 22→32, ITE immunity uses CISPR 35, and domestically use the GB/T 17626 series.

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