ND5 XS Ethernet port grounded?

Yes ND5 RJ45 port is grounded (earthed) 

An STP ethernet shield/screen ideally should be grounded at one point only on the network.     If your NAS also has a metal shouded RJ45 port its best to assume that it finds an earth connection as well via its SMPS & you should (ideally) not have both cables screens connected together.      How to avoid an STP network screen inter-connection;    If your ND5 & NAS connect via a broadband router or switch & it/they do not have metal shrouded ports,  then the screen connection is not 'made'.   If you connect via a switch & it has metal shrouded ports, then you need to somehow break the screen connection & if you have not already bought the cable,  the obvious solution is a UTP (not screened) cable on one or both of the branches.        

For someone who finds networking a bit tricky, compliments on a very sensible question     

Good question [@mention:74075141248275799]. 

I assume the 272 is the same? 

[@mention:1566878603907884] do you know if the Cisco 2960 ports grounded too? If so, I quest I should replace me shielded Supra cable with a UTP one. 

Hi FinkFan,   the Cisco 2960 has metal shrouded ports,  that does not mean the switch itself has its port connected to its own ground/earth,  but for sure it means it carries the connection between STP cable screens.    Rather than replace the Supra with a UTP,  have a think about a UTP M/F coupler,  this will isolate the screen connection.   When I had STP I used a Lindy 90 degree angled connector,  there is "UP" (part No. 71150) & "Down" (part No. 71151) versions.  £4.49+P&P    www Lindy.co.uk 

Thanks Mike. I’ll try one of those out 

Finkfan posted:

Good question [@mention:74075141248275799]. 

I assume the 272 is the same? 

[@mention:1566878603907884] do you know if the Cisco 2960 ports grounded too? If so, I quest I should replace me shielded Supra cable with a UTP one. 

The Cisco 2960 switches usually have a metal shroud around RJ45 connectors which I believe are connected to chassis ground. Cisco require that it’s 2960 switches must be grounded in operation, usually via the safety earth on the mains lead.

General consensus in networking circles is that you should only use grounded metal connectors when the infrastructure has been properly setup so as to avoid induced Earth loops which could cause interference to the Ethernet cable and frame corruption and require data to be inefficiently resent. If using shielded and grounded cables I would always check, just like with using fibre, what the Basic Error Rate is on the link. You need managed equipment to do this... if using consumer equipment I would not use shielded cables, or if you insist on doing so I would ensure I break the shield carefully at one end of the cable, and connect the shielded end to your grounded switch.

Thanks Simon 

Many thanks to all the contributors. Your explanations were very useful and much appreciated.

I have tested the Ethernet shroud connection on my Cisco 2960G 8TC, and it is connected to the mains safety earth.

Curious as to how this affects all these expensive audiophile cables that are cat 7 STP. Do you need to be careful with grounding these to?

You need to be careful of grounding with any STP cable irrespective of the 'Cat' No.
There should be one ground for the audio and one ground for the Ethernet.

Interestingly, measuring my 272, although the Ethernet port is shielded, this doesn't appear to be connected to the mains safety earth even if the grounding switch for the audio side is set to 'Chassis'.

So I was about to experiment with some cat7 STP patch leads with my Uniti, My switch is not a commercial one so has no ground connector to it. The leads are already assembled so what would be best practice if I am to use them. I find this whole grounding earthing things somewhat new to me and I feel I might as well just stick to my normal cat5e or get some cat6.

If the Ethernet ports on your switch have plastic surrounds then there's no problem; as this itself will ensure that you don't have multiple earths on the Ethernet shields.

The Cat rating is irrelevant, the only part of the cable spec that's relevant to this is the shielding (STP, SSTP, SFTP) or not (UTP).

If they are UTP there won't be a problem.

If they are shielded, then...

-    If the switch ports have plastic surrounds - no problem.

-    If the switch ports have metal surrounds - you need to find out if anything else connect to the switch has metal surrounded ports that are earthed.

Some Cat5e cables are shielded but most are not
For Cat6 some are shielded, some are not.
Cat6a are usually shielded, but there are a few that are not.
Theoretically Cat7 don't have to be shielded, but I don't know of any that don't have a shield.

thanks