Using Macs on shielded/grounded ethernet (Cat6a STP)

Discussion in 'Mac OS X Server, Xserve, and Networking' started by sumo.do, Sep 27, 2014.

  1. sumo.do macrumors member

    sumo.do

    Joined:
    Mar 12, 2014
    Location:
    Australia
    #1
    My friend was showing me his network setup the other day which is serious overkill (I'll explain below), but I was wondering if there are issues using Macs (for example the Mac mini) that are not earthed/grounded on a network that is shielded and grounded?

    His setup (roughly):

    Cat6a shielded twisted pair (STP) throughout the network. It is earthed/grounded at the server cabinet to the main earth for the the house. In Australia we have an earth rod cause we use 240 volts. Patch panel, 24 port switch etc is earthed and all internal (i.e. hardwired in the house) cat6a cables have the drain wire attached. He uses cat6a patch cables from the wall socket to the Macs as well. So basically it is a complete cat6a STP network with all the STP ethernet cable earthed through the main house earth point. His view was to make it 10 Gigabit ready. He had it installed so while he knows how to show it off, he does't really understand the questions I have set out below.

    The question is this, based on the above network, is it an issue using earthed STP (and rest of network) on a Mac mini or rMBP (which he has)? They are not earthed like standard PCs are (in my country (Australia)). I was guessing this is not an issue but I pointed out to him that Macs are not earthed.

    Second question: Can he use standard UTP Cat6 (non-shielded and non-grounded) from the wall socket even though his main network is fully STP grounded?

    I am guessing the answers to the above are that is is ok to use non-earthed Macs (and PCs (e.g. laptop on battery) on a fully grounded STP network and that it is also ok to have UTP for the wall-to-mac cable, but I was just wondering if there are risks or is it totally ok. You would think this super modern 10 Gigabit standard would allow for non-earthed computers and cables to be used on it, but if not then he is in trouble.

    Thanks for any comments.
     
  2. satcomer macrumors 603

    satcomer

    Joined:
    Feb 19, 2008
    Location:
    The Finger Lakes Region
    #2
    You have to make the decision but the general rule to when to use Shielded CAT cable is when the Ethernet cable will be close to electrical cable in your network.
     
  3. crazzyeddie macrumors 68030

    crazzyeddie

    Joined:
    Dec 7, 2002
    Location:
    Florida, USA
    #3
    I've always heard that only one end of an STP network needs to be fully grounded for proper functionality. The others should be internally grounded, but don't need a full ground.
     
  4. sumo.do thread starter macrumors member

    sumo.do

    Joined:
    Mar 12, 2014
    Location:
    Australia
    #4
    That was sort of what I was thinking as well. Grounded at the server/rack end and internally grounded through the drain wire to the Mac. From what I can see my Mac mini's RJ45 network port has side metal 'nodules' in the port to allow for earthing to a cable so I am guessing they are designed for earthed/grounded networks.
     
  5. crazzyeddie macrumors 68030

    crazzyeddie

    Joined:
    Dec 7, 2002
    Location:
    Florida, USA
    #5
    The more I think about it, the concern with only grounding on one side has to do with the non-grounded device sending its excess noise/current STP cable (essentially using the STP cable as a ground).

    Having a proper internally-grounded device should prevent this except in case of a full on surge from another input (eg charger).
     
  6. sumo.do thread starter macrumors member

    sumo.do

    Joined:
    Mar 12, 2014
    Location:
    Australia
    #6
    Excuse my lack of knowledge on this, but how are Apple computers internally grounded? (I should note I'm not being facetious, I am genuinely interested) I just assumed there is nil ground/earth as the power plug does not have an earth prong on it. In Australia we have 240 volts with all wall plates having pos/neg and earth (three prong), but a lot of devices (e.g. lamps, clock radio, mac computers) only use the two pos/neg prongs. Is there some sort of capacitor or something inside the Mac allowing for 'internal grounding' as you refer to?
     

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