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I'm looking at cabling our house with Cat6A, & leaning towards using S/FTP.

If I use shielded cable is grounding necessary if;

Setup: Router -> PoE capable network switch -> computers/TV's/Cameras/etc.

-I'm ok with (some) interference.

-Using PoE PD, powered by PoE network switch.

-Network switch is metal & has its own earth (via power plug).

In cases of lightning:

-if lightning hits the area nearby or

-if lightning hits house directly

How then is earthing the shielded cable relevant?

Everything I've read about earthing/grounding shielded Ethernet mentions doing so for sake of tapering off interference & giving it some place to go.

I know if UTP is used I don't need to ground, but that's not my question. More interested in if S/FTP is used & grounding isn't done, I know there will be interference.

ReturnVoid
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  • See the answer to [this question](https://networkengineering.stackexchange.com/q/39069/8499). – Ron Maupin Mar 23 '18 at 21:05
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    An improperly grounded shield will cause the cable to not perform as well as unshielded cable. FYI, category cable is specifically UTP. Some cable manufacturers add shields because the cable is poorly constructed and could not pass the category test without the shield. In any case, you will need this to be installed by a certified cable installer with the (very) expensive test equipment to verify that it was properly installed. This is not something that can be done for Category-6a cable without a lot of experience and the proper test equipment. – Ron Maupin Mar 23 '18 at 21:12
  • I know it won't perform as well. My question is around earthing/grounding being required, not performance of different cable types. – ReturnVoid Mar 23 '18 at 21:33
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    Look at the link I provided. An ungrounded shield can cause severe performance problems, including to the point that the cable is useless due to the increased noise from the ungrounded shield. You cable installer should explain such things. – Ron Maupin Mar 23 '18 at 21:36
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    "_An STP cabling system also requires good grounding and earthing practices because of the presence of the shield. An improperly grounded system can be a primary source of emissions and interference._" – Ron Maupin Mar 23 '18 at 21:41
  • Thanks, still isn't the question I've asked. Re-read OP. This is more in line with what I'm talking about: https://diy.stackexchange.com/questions/98415/where-does-the-electricity-induced-in-the-shield-flow-from-a-cat6a-s-ftp-cable/98455 – ReturnVoid Mar 23 '18 at 21:57
  • I did not post an answer, I posted a comment. If your shield isn't grounded, the cable itself will cause all types of interference with itself, and may not function correctly. It will detrimentally reflect the internal cable noise back into the cable. You seem to be under the mistaken belief that it is primarily to protect the cable from external noise. You must properly ground shielded cabling. – Ron Maupin Mar 23 '18 at 22:01
  • @ReturnVoid Instead of telling someone to read the question again, just clarify the question, any event a ground is about being able to remove the EMI from a signal (or/and having a reference to ground). I realize a cable can’t do anything (although that’s technically not true) but the device it’s connected to can – Ramhound Mar 23 '18 at 22:01
  • TIA and ISO standards provide one additional step for the grounding of screened and shielded cabling systems. Specifically, clause 4.6 of ANSI/TIA-568-B.1 and clause 11.3 of ISO/IEC 11801:2002 state that the cable shield shall be bonded to the TGB in the telecommunications room, and that grounding at the work area may be accomplished through the equipment power connection. – Tim_Stewart Mar 23 '18 at 22:25
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    You may want to give the paper in this answer a read. I think the interference is only an issue if you have these cables bundled. (Alien cross-talk). The lightning question could be answered if we knew whether or not you have a lightning rod attached to your house.https://superuser.com/questions/1295256/s-ftp-or-u-ftp-when-wiring-a-house-with-cat6a-cabels-for-10gbe/1295287#1295287 – Tim_Stewart Mar 23 '18 at 22:27

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