2014/30/EU Directive became effective. The Directive requires that products must
not generate unwanted electromagnetic pollution or interference, and that products must be immune to a reasonable amount of noise pollution or interference. EMC testing is required to be carried out on any electrical or electronic product thatmay either cause electromagnetic radiation or be affected by it. The Directive means equipment manufacturers
mustmake considerations early in the electrical and electronic design process to ensure the equipment will pass EMC test requirements. Many design techniques are therefore adopted
to limit EMI emissions at source or to protect susceptible equipment. Circuits may be partitioned, segregating EMC critical and non- critical areas. A good grounding scheme may be implemented, preventing earth loops leading to unwanted signals being radiated. Shielded cables and enclosures are often utilised, providing barriers to unwanted radiated noise. However, a significant oversight is often at the
point of cable entry into an electrical enclosure. By adding openings in enclosures, pathways are created to allow noise to breach the shielded enclosure. Unterminated or poorly terminated cable shields can allow noise to be carried into the enclosures, acting as antennas to radiate noise onto sensitive circuits. Grounding the cable shield effectively
inside a cable gland at point of entry eliminates a potential noise pathway and
reduces the risks of radiated emissions being carried into the enclosure. Cable glands, which employ a robust 360
degree circumferential termination of the cable screen, shield braid or armour (e.g. with a cone and clamping ring, or a dedicated continuity device) in their metallic body, contribute to the electromagnetic compatibility of installations through reliable low impedance connections. These stats are backed up by a number of industry studies into the role they can play in EMC protection. One such independent study was
commissioned by ourselves in 2021 and carried out by a third party, Eurofins E&E. 3 Metre Class B Radiated Emission Measurement tests were carried out in accordance with EN 55032, to gauge the performance of cable glands terminated onto screened, braid shielded and armoured cables. The results proved categorically that using a reliable 360 degree termination of the shield or metallic cable layer inside the cable gland improved noise attenuation throughout the frequency range.
When it comes to improving electrical safety, whether it be with the intention of protecting people, power supplies or data, it’s imperative that every potential step is taken to ensure the systems are the most robust they possibly can be. As such, suitably proven cable glands needs to be given proper consideration – and
CMP’s TruSeal TSZ cable glands are designed for superior EMC performance, providing 360 degree contact around screen
circumference. These have been third party tested, proving they can attenuate EMI across a wide range of frequencies
if this can be done within the remit of the EMC Directive then it would ensure they are.
southern@easyfairs.com
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