When installing cabling for Ethernet purposes, the question often arises: does one want/need simple UTP or any of the shielded variants, i.e. F/UTP, S/UTP, SF/UTP, U/FTP, F/FTP, S/FTP or SF/FTP, often labelled FTP or STP?
Most sites with information on the topic are from cable manufacturers or distributors, and all the shielded variants are of course deemed superior (and they are more expensive), but with very little justification. Beyond the additional cost of the cable (and sockets), shielded variants also require grounding, which complicates installation.
Cat6E, which supports up to 10G Ethernet, only requires UTP. Wikipedia states that:
Cable shielding may be required in order to avoid data corruption in high electromagnetic interference (EMI) environments
Are there real, objective, guidelines/rules on when one needs more that UTP for Ethernet? What are "high EMI environnements"? Is this something you are likely to find in regular offices (I've seen vague references to lighting equipment), or is this just for some extreme cases one is unlikely to encounter outside of industrial premises or research labs?
In my case, I'm interested about "run of the mill" 100 Mbits/s or Gigabit Ethernet, nothing fancy like 2.5G, 10G, 25G, 40G (I understand the latter two require various forms of shielding).
Some places also indicate (without justification) that shielded cables are required/better for PoE applications, though I fail to understand the relationship.