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IEC TR 62493-1:2013 — Lighting Equipment EMF Exposure Assessment
Assessment of lighting equipment related to human exposure to electromagnetic fields — Part 1: Results of the EMF measurement campaign
Van der Hoofden Probe
The Van der Hoofden probe is a specialized EMF measurement head designed to simulate the human head exposure to electric and magnetic fields from lighting equipment. It consists of a set of electrodes and a measurement network.
The Van der Hoofden probe is a specialized EMF measurement head designed to simulate the human head exposure to electric and magnetic fields from lighting equipment. It consists of a set of electrodes and a measurement network.
Key Finding
The rectification stage in AC-powered LED drivers is a major contributor to EMF emissions. Designers should pay special attention to input filtering and PCB layout in the AC-DC conversion stage to minimize emissions in the 20 kHz to 10 MHz range.
The rectification stage in AC-powered LED drivers is a major contributor to EMF emissions. Designers should pay special attention to input filtering and PCB layout in the AC-DC conversion stage to minimize emissions in the 20 kHz to 10 MHz range.
Engineering Insight
For LED luminaire designers aiming to minimize EMF emissions: (1) use metallic enclosures where possible, (2) incorporate adequate input filtering in the LED driver, (3) ensure proper PCB layout with minimal loop areas, and (4) consider adding a ferrite bead on input lines.
For LED luminaire designers aiming to minimize EMF emissions: (1) use metallic enclosures where possible, (2) incorporate adequate input filtering in the LED driver, (3) ensure proper PCB layout with minimal loop areas, and (4) consider adding a ferrite bead on input lines.
Overview of the EMF Measurement Campaign
IEC TR 62493-1, published in 2013, is a Technical Report that presents the results of a comprehensive EMF measurement campaign conducted jointly by the VDE Test and Certification Institute and ZVEI (German Electrical and Electronic Manufacturers Association). The campaign tested a broad range of luminaires using different lamp technologies against the requirements of IEC 62493:2009, which specifies the assessment of lighting equipment related to human exposure to electromagnetic fields.
The measurement campaign used the Van der Hoofden head probe in the frequency range from 20 kHz to 10 MHz. A total of 75 luminaires from different manufacturers were tested, covering various lamp technologies including incandescent, halogen, fluorescent, compact fluorescent (CFL), LED, and high-intensity discharge (HID) lamps.
Key Findings and Influencing Factors
The campaign revealed that the vast majority of tested luminaires (over 85%) complied comfortably with the IEC 62493 limit value of F = 0.85. The frequency distribution showed that most measured values clustered well below 0.3, with only a small number of outliers approaching or exceeding the limit. One notable finding was that a luminaire type exhibited significantly higher values (F > 3) when powered by AC mains, but when the same luminaire was powered by DC, the measured value dropped dramatically, indicating that the AC rectification stage was the primary source of EMF emissions.
The study evaluated several influencing factors: type of luminaire, presence and type of lamp cover, lamp technology, protection class, outer shape, total rated power, and enclosure material. LED luminaires generally showed higher EMF values compared to traditional incandescent lamps, primarily due to the switching power supplies used in LED systems.
Practical Recommendations for Luminaire Design
Based on the measurement campaign results, the report offers several practical recommendations for luminaire designers. The material of the enclosure plays a significant role: metallic enclosures provide inherent shielding and generally result in lower EMF values compared to plastic enclosures. However, even plastic-enclosed luminaires can achieve compliance with proper internal shielding and component layout.
More significant was the protection class: Class I luminaires (with protective earth connection) generally showed lower EMF values than Class II luminaires, as the earth connection provides a return path for common-mode currents. The total rated power showed a weak correlation with EMF values, suggesting that power alone is not a reliable predictor of EMF performance.
| Lamp Technology | Average F Value | Range (Min-Max) | % Below 0.85 |
|---|---|---|---|
| Incandescent / Halogen | 0.08 | 0.03 – 0.25 | 100% |
| Fluorescent (T5/T8) | 0.12 | 0.04 – 0.40 | 100% |
| Compact Fluorescent (CFL) | 0.15 | 0.05 – 0.50 | 98% |
| LED (with driver) | 0.22 | 0.05 – 0.95 | 92% |
| HID (metal halide, HPS) | 0.10 | 0.04 – 0.35 | 100% |
Frequently Asked Questions
Q: What is the F value in IEC 62493?
The F value is a single figure of merit representing the combined EMF emission of a luminaire across the frequency range of 20 kHz to 10 MHz, weighted against the applicable limits at each frequency. The pass/fail threshold is F = 0.85.
Q: Why do LED luminaires tend to have higher EMF values?
LED luminaires require switching power supplies (LED drivers) that operate at high frequencies, typically in the range of 30 kHz to 1 MHz. These switching converters generate electromagnetic emissions.
Q: Does the material of the luminaire enclosure affect EMF emissions?
Yes, significantly. Metallic enclosures provide electromagnetic shielding that reduces radiated emissions. Plastic enclosures offer no inherent shielding, so the internal electronics must rely on circuit-level design techniques.
Q: Can a luminaire with plastic enclosure still pass IEC 62493?
Absolutely. The measurement campaign showed that many plastic-enclosed luminaires passed comfortably. Key design practices include proper input filtering, minimized switching loop areas, and strategic placement of the driver circuit.
