Multiple Conductor Cable is often used for signal transmission, and thus is also often shielded in order to reduce the effects of EMI on your application’s signal quality. Shielding blocks unwanted EMI interference, conducting it to ground before it can reach your important signal conductors.
Shielding is not always required for every cable, but it should be one of the first things you consider when selecting cabling for noisy environments such as factory floors or near power transmission systems. A few moments’ forethought in selecting the appropriate shielding for your application can save you weeks of troubleshooting down the road.
So which shielded cable is right for you? In general, there are 3 main varieties of cable shielding - Foil, Braid and Spiral.
This table compares the three different shielding types side by side; with this, you should be able to identify the best shielding type for your application requirements.
| Foil | Braid | Spiral | |
|---|---|---|---|
| Shielding Effectiveness | Moderate | Good | Moderate |
| Flexibility | Good | Moderate | Very Good |
| Mechanical Strength | Moderate | Good | Moderate |
| Advantages | Thin, low cost | Good overall performance | Flexibilty |
| Disadvandatages | A risk of tear under repeated flexing | Less effective at high frequencies | Poor high frequency performance due to inductance of spiral wire strands |