Cable shielding density refers to the quantitative indicator of the shielding capability of the cable shielding layer towards electromagnetic signals.
It is usually expressed as a percentage, reflecting the extent to which the shielding layer can block or attenuate electromagnetic interference. The shielding density depends on factors such as the thickness of the braided wire and the tightness of the braiding.
1. There are various common braiding densities for cable shielding layers, and the following are some of the more common ones: • 70%: It can resist external electromagnetic interference to a certain extent and is suitable for general electrical equipment connections with relatively low electromagnetic shielding requirements.
• 80%: It can effectively suppress electromagnetic interference and is commonly used for internal wiring in ordinary electronic devices and office equipment.
• 90%: The shielding effect is good, suitable for places with certain requirements for electromagnetic environment, such as some industrial automation control systems.
• 95%: It has high shielding performance and is commonly used in cables that are sensitive to electromagnetic interference, such as communication and data transmission cables.
2. National standards have different requirements for cable shielding density: • For single-core shielded wires with a nominal cross-section of 0.12mm² or less, the braiding density of the shield should be no less than 60%.
• For other shielded wires, the shielding density should be no less than 80%.
• Computer cables: The individual shielding density should reach 85%, and the overall shielding density should reach 95%.
• Control cable: When using round copper wire for braided shielding, the braiding density should not be less than 80%.
In addition, for the braided shielding of cable copper wires, it is usually required that the coverage density be greater than 90%, and the diameter of the braided wire should be greater than 0.1mm. When the metal tape is produced by wrapping, the overlap rate should generally be no less than 15%, but specific standards such as TICW/06 stipulate that the overlap rate of the shielding metal tape should be no less than 25%.
• 98%: Belongs to high shielding density, suitable for special fields with stringent electromagnetic shielding requirements, such as medical equipment, aerospace, etc.
• 99% and above: Provides an extremely excellent shielding effect, generally used in military, high-end scientific research, and other occasions where electromagnetic compatibility is highly required.
The selection of braiding density for the cable shielding layer requires comprehensive consideration of various factors such as application scenarios, equipment requirements, and cost.