Practical Guidelines for Effective Shielding

Posted on Wednesday, November 19, 2014 by Kimberly Versaw

1. Make sure you have a cable with sufficient shielding for the application’s needs.  In moderately noisy environments, a foil alone may provide adequate protection.  In noisier environments, consider braids or foil-braid combinations.

2. Use a cable suited to the application.  Cables that experience repeated flexing usually use a spirally wrapped shield rather than a braid.  Avoid foil-only shielding on flex cables since continuous flexing can tear the foil.

3. Make sure the equipment that the cable is connected is properly grounded.  Use an earth ground wherever possible and check the connection between the ground point and the equipment.  Eliminating noise depends on a low resistance path to ground.

4. Most connector designs allow full 360° termination of the shield.  Make sure the connector offers shielding effectiveness equal to that of the cable.  For example, many common connectors are offered with metal-coated plastic, cast zinc, or aluminum backshells.  Avoid both overspecifying and paying for more than you need or underspecifying and getting poor shielding performance.

5. Ground the cable at one end.  This eliminates the potential for noise inducing ground loops.  A shielded system is only as good as its weakest component.  A high-quality cable is defeated by a low-quality connector.  Similarly, a great connector can’t do anything to improve a poor cable.

For more information on shielding and Alpha Wire shielding options, check out our white paper on shielded cables!


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