EMC Testing Standards

Key Takeaways

• EMC testing standards standardize electromagnetic interference testing procedures so that the pass certificate obtained after testing is accepted in the global electronics market. 

• There are various agencies that issue EMC testing standards: IEC, IEEE, CENELEC, FCC, RTCA, MIL-STDs, etc. 

• IEC 60601 is the EMC testing standard for medical electrical equipment.

Specific EMC testing  standards are used for medical equipment

Electromagnetic compatibility (EMC) is necessary for any electronic product hitting the market. EMC confirms the ability of a product to operate normally under an electromagnetic environment. If a product is deemed electromagnetically compatible, there will not be any generation, propagation, or reception of spurious signals pertaining to electromagnetic interference from this product. Declaring a product electromagnetically compatible can only happen if the product gets a pass certificate for electromagnetic interference testing.

Electromagnetic interference testing simulates the electromagnetic environment and checks whether the emissions and immunity of a product are within acceptable limits. EMC testing standards set the guidelines for testing and differ for medical equipment, consumer electronics, automotive systems, military equipment, etc. 

The Importance of EMC Testing Standards

EMC testing standards standardize electromagnetic interference testing procedures so that the pass certificate obtained after testing is accepted in global electronics markets. The test setup, test procedure, and measuring instruments all need to be standardized to validate that the obtained reading is within acceptable limits. 

Who Sets EMC Testing Standards?

There are a variety of agencies that issue EMC testing standards, including:

• International Electrotechnical Commission (IEC)
• Institute of Electrical and Electronics Engineers (IEEE)
• European Committee for Electrotechnical Standardization (CENELEC)
• Federal Communications Commission (FCC)
• Radio Technical Commission for Aeronautics (RTCA)
• United States Military Standards (MIL-STDs)

These regulatory bodies devise the testing plans and standards for each class of equipment, so you will need to follow the appropriate standards based on what you are testing. For example, if you are planning to test medical equipment, you need to follow the guidelines and directives associated with medical class equipment.

Let’s take a look at the performance criteria set by the IEC for EMC testing standards.  

IEC Performance Criteria in EMC Testing Standards 

The EMC testing standards issued by the IEC falls under IEC 61000 standards. The IEC 61000 family defines various electromagnetic phenomena, reviews the test methods for each electromagnetic event, and gives the allowable limits of emissions and immunity levels for the device under test.

In an EMC test, the device under test is evaluated for its immunity characteristics under three criteria. Usually, the criteria to which the device under test belongs is specified in the test plan. 

Criteria A

Equipment should operate normally during and after EMC testing. The performance level of the equipment should be as specified by the manufacturer. There should not be any performance degradation or loss of function in the equipment during or after testing. In case the manufacturer has not given the equipment’s performance level, it is the responsibility of the user to derive the performance level or permissible loss from the product specification or datasheet. 

Criteria B

Equipment should operate normally after EMC testing. No degradation of performance or loss of function is permitted during post-operation. It is important to note that criteria B permits the degradation of performance during testing but criteria A does not. 

Criteria C

In this criteria, a temporary loss of function is permitted, provided the function is of a self-recovery type or can be restored with the introduction of control.

Selecting EMC Test Levels

The  EMC testing standards set by the IEC define the immunity of a device under test with different levels: level 1, level 2, level 3, level 4, etc. Generic EMC standards guide the immunity test levels being applied to a given device under test in accordance with the device’s electromagnetic environment classes. By considering the most realistic installation and electromagnetic environmental conditions, immunity test levels for a given device are selected.

As an example, let’s take a look at EMC testing standards for medical devices. 

EMC Testing Standards for Electronic Medical Devices

EMC testing standards for electronic medical devices and systems follow IEC 60601-1-2. This standard defines the performance levels and safety requirements of electronic medical devices and systems in the presence of electromagnetic interference. The testing of medical equipment needs to be carried out by accredited laboratories following the IEC 60601-1-2 standards.

Apart from electromagnetic interference from adjacent electronic devices, medical equipment manufacturers are advised to apply the same emission and immunity requirements for automobiles and ambulances. For medical devices in railway or aviation environments, test levels need to satisfy the limits specified by the EMC standards for the respective electromagnetic environment classes.

Like the EMC testing standards for medical devices, EMC standards for various product families—such as consumer electronics, automotive systems, military equipment—exist. By adhering to the appropriate EMC testing standards, a pass certificate can be achieved by the device under test. Achieving this pass certificate is proof that the device is validated indirectly by regulatory bodies.

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