How Does Cable Shielding Work Anyway?


Shielded Ethernet cable was designed for use in environments where electromagnetic interference (EMI) and radio frequency interference (RFI) are present.

Examples of such areas include manufacturing, automation and Industrial control applications where motors, generators, transformers and other noise emitting industrial machines are in use.

L-com offers several variations of shielded Ethernet cables for use in these environments including single foil shielded assemblies for areas with minimal EMI and RFI. Although Foil shielding provides 100% coverage of the conductors, it is hard to effectively terminate to connectors and offers high resistance which does not provide the best path to ground.

L-com also manufactures double shielded Ethernet cable assemblies with foil and braid shield for use in applications where heavy EMI and RFI is present.Braided shield generally offers 60%-85% shielding and can only offer about 95% coverage at best. The mass of the braid is higher than a foil shield and thus provides better conductivity and offers a secure connection to the connectors at the cable ends providing an excellent ground.The shielding can deal with EMI and RFI in two ways. It can reflect the energy.

Or, it can pick up the interference and conduct it to ground, keeping the EMI and RFI away from the twisted pairs located under the shielding.Whether the EMI/RFI is reflected off the shield or “rides” the shield to ground, some energy can still pass through the shielding, but since it is so highly attenuated it will not cause interference.L-com offers many types of single and double shielded Ethernet cable assemblies and bulk cable including different jacket options, colors and lengths.If you can’t find what you’re looking for off-the-shelf, L-com can custom manufacture shielded Ethernet cables to your exact specifications.


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