Multiconductor cables which contain unshielded or individually shielded wires, or both, frequently
have an overall shield provided for both physical protection and to provide supplemental electromagnetic
shielding. Such overall shields should be grounded at each end of the cable run to provide a continuous rf shield
with no breaks.
For long cable runs where the cable is routed through one or more intermediate connectors, the
overall shield should be grounded to the frame or case of junction boxes, patch panels, and distribution boxes
along, the cable run.
For maximum shielding effectiveness, the overall shield should be effectively bonded as shown in
Figures 3-7 and 3-8 with a low impedance connection to the equipment case, enclosure wall, or other
penetrated (metal) shield. The best way to bond the overall shield to a connector is to run the shield well inside
the connector shell and provide clean metal-to-metal circumferential contact between the shield and the shell.
If the connector is not involved, shortest practical lengths of connecting strap or jumper should be used.
Figure 3-4. Effect of an Unbalanced Cable on the Single-Point Ground