I currently have three coax runs to each TV, one for Directv, one for OTA and one for cable. The Directv coax is connected to the receiver (either H20 or H24) and the OTA coax is connected to the H20 or AM21 (for H24) The cable coax is connected to the TV's RF input. The TV and receiver are connected via HDMI. The TVs are Panasonic plasmas and LG plasmas, if that matters.
Are the grounds of the three different coax families separate in this situation, or are they sharing a common ground? The reason I ask is that I'm looking into wall plates for the three coaxes, which currently home run directly to where they connect at the TV/receiver.
Some wall plates are plastic, or metal using plastic inserts and thus non-conductive between the three coaxial cables. Others are all metal, and as far as I can tell would offer a conductive path between the shields of the three coaxial cables. I would prefer the all-metal solution since it would be more durable, as I'm not impressed with how easily plastic coaxial keystone inserts pop out if you even look them at cross eyed. I don't want to deal with them popping out anytime a TV is rotated around a bit.
I want to determine if using the all-metal solution that would appear to share ground is something I should avoid. Of course, if it turns out I'm already sharing grounds due to the Directv/OTA being connected to H20s together, and the cable perhaps also sharing ground from the TV via the HDMI cable then obviously any additional ground sharing doesn't matter.