EMI (electro-magnetic interference) – a legal and insurance requirement

//EMI (electro-magnetic interference) – a legal and insurance requirement

EMI (electro-magnetic interference) – a legal and insurance requirement

It is rather ironic that in a modern world where we are concerned about greenhouse gases, smoking, genetically modified foods and nutrition, the consumer often spends good money unwittingly exposing themselves to possible sources of high EMI. This is especially in the case of modern solid-state lighting such as LED lamps and even more so when dimming is activated.

All electronic devices such as dimmers or LED lamps emit electromagnetic energy and there are very clear international specifications as to the maximum levels of these emissions. Exposure to high-frequency energy magnetic fields, even as low as 100kHz, can produce biological effects and possibly have health consequences. Sources of high EMI can also interfere with electronic devices such as AV equipment, communications systems, pacemakers, etc. Furthermore, the lifetime of electronic LED drivers (internal or external) can be reduced if a lamp is for instance controlled with a non-compliant dimmer which allows a too high inrush current into the driver with every mains cycle. Additional negative side-effects could include inconsistency in the dimming behaviour of LED lamps, possibly undesired flickering or shimmering especially at low light intensities and perhaps a premature failure of dimmers. For the reasons above, all and any lighting related products must comply

Furthermore, the lifetime of electronic LED drivers (internal or external) can be reduced if a lamp is for instance controlled with a non-compliant dimmer which allows a too high inrush current into the driver with every mains cycle. Additional negative side-effects could include inconsistency in the dimming behaviour of LED lamps, possibly undesired flickering or shimmering especially at low light intensities and perhaps a premature failure of dimmers. For the reasons above, all and any lighting related products must comply

Additional negative side-effects could include inconsistency in the dimming behaviour of LED lamps, possibly undesired flickering or shimmering especially at low light intensities and perhaps a premature failure of dimmers.

For the reasons above, all and any lighting related products must comply with the International compulsory standards, EN55015/CISPR15 (part of the European EMC directive) or the South African SANS 215 standard (ICASA is the regulatory authority as per Government Gazette). If a lighting related product complies with this standard it implies that it is safe for humans and does not cause interference with any other electronic device. There are currently a large number of LED products in the South African market that do not comply with this standard, which when installed becomes a distributed source of high emissions. There are also a number of dimmers in the market which do not comply. If a consumer is unfortunate enough to end up with non-compliant dimmers and LED lamps, the result is effectively a much amplified electromagnetic emissions footprint.

The severity of the “amplification” effect mentioned above can be illustrated by practical measurements of some commercially available products in the market.

Figure 1 shows the measured conducted emissions in a fairly narrow frequency range of 100kHz to 1 MHz of a typical CISPR15 compliant LED and dimmer. The white trace is the reference value when power is off. As can be seen from the yellow trace the conducted emissions are typically not more than 20dBuV above the reference value and the combined installation is legal.

Figure 2 shows the result of the same LED but the dimmer is not compliant. It can be seen that sections of the yellow trace are actually off the scale which implies that the lighting circuit is not compliant with regulations.

Figure 3 shows the measured emissions of a non-compliant LED operated without a dimmer in the circuit. Although the emissions are very high and illegal it is at least still within 30dBuV of the reference value. The result, however, becomes shocking when the non-compliant LED of Figure 3 is dimmed with a non-compliant dimmer.

It can be seen from Figure 4 that the emissions are now extremely high and such an installation would be completely illegal, causing interference with electronic equipment. To avoid possible problems with LED’s and the dimming thereof, always ensure that all lighting related products comply with the standards – it is after all a legal requirement and non-compliance is subject to prosecution!

2017-07-11T14:01:47+00:00

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