ECN Forum Forums General Topics of the Trade Voice - Data - Video Discussion Residential issue which has stumped 3 electricians

Any Occupancy Sensors or Dimmer switches on this circuit?

First off, agreeing with the difficulty in communication/translation here.

One interpretation I haven't seen yet focuses on the splitters "going bad". I'd suggest a significantly-different potential at Comcast's ground point with reference to the rest of the system, causing current to flow through the devices and coax, damaging the bits inside the "splitter," whatever the OP may be applying that term to.

OP's "electrician" seems to be implying that there's 8V between "everything" and "ground," so I'm going with "OP's ground isn't very well grounded."

This sounds similar to what may happen over the coax with bad grounding and fault in another residence. a coax isolator, and local bonding to ground may help.
This could probably be found to a better price.
http://tinyurl.com/d3bjfy

dsk