Product category:
Cabling, Conduit, Accessories and Signal Conditioning
News Release from: KEC | Subject: EMC glands and backshells for fibre optic cables
Edited by the Engineeringtalk Editorial
Team on 09 February 2001
EMC glands and backshells modified for
fibreoptics
KEC has modified standard EMC glands and backshells so that they can be used to secure fibre optic cables without damaging the fragile fibre optic strands
KEC, the Aldermaston based EMC interconnect specialist, has modified standard EMC glands and backshells so that they can be used to secure fibre optic cables without damaging the fragile fibre optic strands Although fibre optic transmission is not susceptible to EMI/RFI, the hole where cables enter the housing or enclosure creates a potential interference path
This article was originally published on Engineeringtalk on 30 Mar 2000 at 8.00am (UK)
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Normal glands used to secure the holes tend to crush the delicate fibre cable bundle and the design objective was to produce a system that would electrically seal the panel or bulkhead hole while protecting the sensitive and fragile fibre optic system.
To achieve this KEC took a standard KG2 screened gland that uses an IRIS spring and modified it to accept a special aluminium adapter tube that slips between a length of outer screen and the softer protective layers covering the fibre optic cables.
In the case of a fibre optic bundle that has a very loose fitting or no outer jacket a soft woven metal braid can be interwoven around the individual fibres.
This braid is then passed through a slot in the aluminium tube and the tube is rotated.
This has the effect of drawing in the braid, electrically sealing the bore of the tube and firmly, but gently, gripping the individual fibres.
Where a fibre optic bundle with a close fitting outer jacket is used, the interweave can be wrapped directly round the outer jacket then taken through the slot in the tube before the winding in process is completed.
This bundle is then passed through the gland and once in position the compression nut of the gland is tightened trapping the length of outer braid.
Because of the shape of the gland, this tightening causes the IRIS spring to close down on to the braid and aluminium tube making a good screen contact through a full 3600 while protecting the fibre cables.
The length of the outer braid used is determined by the degree of screen protection required.
Environmental sealing can be achieved by the inclusion of an 'O' ring seal in addition to the IRIS spring.
The same technique is applied to the KC 2100 and KC 2300 backshells for circular connectors that use the same IRIS spring system for screen termination.
The system is simple, lightweight and easily reworkable and very high levels of screening protection can be achieved.
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