EN IEC 61000-5-7 Degrees of Protection Provided by Enclosures Against Electromagnetic Disturbances (EM Code)

The standard "EN IEC 61000-5-7 Electromagnetic compatibility (EMC) - Part 5-7: Installation and mitigation guidelines - Degrees of protection provided by enclosures against electromagnetic disturbances (EM code)", which has its origin in a European standard and was subsequently published by the International Electrotechnical Commission (IEC), describes the performance requirements, test methods and classification procedures for the degrees of protection provided by empty enclosures against electromagnetic disturbances at frequencies between 10 kHz and 40 GHz.

Shielding protection is measured to demonstrate that the enclosure provides sufficient electromagnetic energy shielding to support acceptable performance of completed and assembled units when tested to applicable IEC standards.

The primary purpose of this standard is to provide a repeatable method for evaluating the electromagnetic shielding performance of empty mechanical enclosures including cabinets and subracks and to specify a marking code that allows a manufacturer to select an enclosure with a known ability to attenuate electromagnetic fields.

Requirements for immunity to various types of electromagnetic disturbances, including lightning and high altitude electromagnetic pulse (HEMP), should be considered by manufacturers when determining the need for application of this standard for particular equipment and applications and the specific enclosure shielding requirements required as a function of frequency.

The adoption of a classification system in this standard ensures, to the greatest extent possible, uniformity in the methods of describing the protection against electromagnetic voltages provided by an enclosure. This ensures that not only the equipment within the enclosure is protected from external electromagnetic voltages, but also the external equipment is protected from internally generated electromagnetic voltages.

For the purposes of this standard, the following terms and definitions apply:

• Degree of protection: It refers to the degree of protection provided by an empty enclosure against the transmission of electromagnetic energy from outside to inside or from inside to outside.
• Electromagnetic disturbance: Any electromagnetic phenomenon that degrades the performance of a device, equipment or system.
• Degrees of protection (EM code): Refers to a coding system that indicates the degree of protection an enclosure provides against the passage of electromagnetic energy.
• Immunity level: The maximum level of a given electromagnetic disturbance event at which a given device, equipment or system can operate at the required performance level.

The frequency range generally covered by this standard is 10 kHz to 40 GHz. This standard applies to empty mechanical enclosures such as cabinets, chassis, and subracks. It ensures that, after assembly, the enclosures provide sufficient field attenuation to meet the immunity requirements of all equipment covered by the other parts of the IEC 61000 series of standards. This standard helps manufacturers select enclosures with predictable shielding performance based on frequency-dependent criteria.

The EN IEC 61000-5-7 standard outlines a repeatable measurement process. Specifically,

• Shielding effectiveness measurement: The enclosure is tested empty at frequencies from 10 kHz to 40 GHz.
• Evaluation zones: In facility test laboratories, shielding is measured from various angles (e.g., front, side, top) using antennas and vector network analyzer equipment.
• Performance levels: Results are assigned levels between 0 and 1 based on minimum dB attenuation thresholds in each frequency band.
• EM code assignment: A composite code encodes the degree of protection of the enclosure per band.

This standard is commonly used by manufacturers of critical infrastructure for electromagnetic compatibility (EMC) (e.g., telecom, industrial control, medical systems, military, aerospace). It is effective for planning, testing, and marking enclosures (often referenced in EMC test reports). It supports a risk-based EMC compliance approach, ensuring shielding is compatible with real-world threats beyond the fundamental emission limits.

The EN IEC 61000-5-7 standard is important because it provides a systematic and verifiable means of assessing and ensuring the electromagnetic shielding performance of enclosures used in electronic systems. This standard is considered important for the following reasons:

• Protects electronic systems from electromagnetic interference (EMI): Electromagnetic interference can disrupt or damage sensitive electronic systems, especially in mission-critical or high-reliability environments such as aerospace, telecommunications, medical, and defense. This standard helps verify that enclosures effectively attenuate external electromagnetic fields and reduce the risk of system failure from EMI.
• Provides a standardized measurement method: Without this standard, different manufacturers might use different, incomparable methods to claim protective performance. This standard allows for head-to-head comparisons between products by defining a repeatable testing method and classification system.
• Introduces the EM code for performance labeling: This standard defines a simple code that labels the shielding performance of an enclosure across frequency bands. This allows engineers and specifiers to quickly assess whether an enclosure meets the EMC requirements of their systems.
• Supports system-level electromagnetic compatibility (EMC): EMC compliance isn't just about circuit board design; the physical enclosure also plays a major role. The EN IEC 61000-5-7 standard supports compliance by relating enclosure shielding performance to broader EMC requirements.
• Enables predictive design: by using enclosures tested to this standard, engineers can estimate the EMI immunity of a complete system before full integration or field testing. This minimizes trial-and-error, redesign, and compatibility errors late in the development process.
• Assists with risk-based EMC planning: Particularly in environments where external threats such as lightning, HEMP, or radar interference are likely, this standard helps define a risk-based protection strategy. It is commonly used in military, aerospace, medical, and industrial control applications.

In conclusion, the EN IEC 61000-5-7 standard is a fundamental standard within the EMC hierarchy and complements other parts of this standard by focusing on physical enclosure protection. It is a fundamental tool for designing, evaluating, and certifying enclosures based on measurable electromagnetic shielding levels.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, boasts a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the standard "EN IEC 61000-5-7 Electromagnetic compatibility (EMC) - Part 5-7: Installation and mitigation guidelines - Degrees of protection provided by enclosures against electromagnetic disturbances (EM code)."