The third-wire deck cable is categorized as a “Level 1” in terms of susceptibility to interference (according to the IEEE
518 standard) and must satisfy the following installation requirements:
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If the deck cable crosses any other cables, then it must do so at a 90º angle to minimize noise coupling. |
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If the deck cable runs parallel with other cables, then the spacing between these cables must follow the deck cable layout
and spacing recommendations. |
The third-wire deck cable should be installed as a single piece whenever possible. This ensures shield integrity over the
cable run and eliminates the risk of significant mismatch in the cable impedance. If splices are unavoidable, then follow
these requirements:
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Use the same cable type for all sections. Using different cable types or sizes may cause signal loss and slow data rates. |
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Minimize the length of the splice and ensure that the shield is restored over the splice area. Ensure that the shield on the
spliced section is in full 360º contact with the shield at the end of the spliced section. |
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Make sure that the shield is not grounded/earthed inadvertently at the location of the splice. The shield of the spliced deck
cable should follow the same grounding technique as if it were a single piece. |
NoteTo prevent ground loop problems, your installation may require multiple shields. An outside shield (such as a braid, tray,
or conduit) is grounded through extremely short jumpers at frequent intervals, and an inside shield is grounded at one point
only. This technique ensures optimum shield grounding at both the low and the high end of the frequency spectrum.