I wish to know the specification that Ethernet adapter manufacturers should comply with regarding the electrical insulation/isolation between the data cable (RJ45 socket) connections and the Ethernet adapter circuitry earth.
Specifically the maximum permitted voltage and typical insulation resistance.
I am asking this question because the is an issue of un-reliable Ethernet comms between a local area network and a particular industrial control equipment (Omron) and one of the engineers has suggested that it might be an "Earth loop" problem.
Personally, I think that this is highly unlikely as there are several other industrial equipments on the same site that use the local area network without any problems and the eqipments are earthed quite well.
the site uses Cisco Catalyst Ethernet switches model 3650G