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

Hello all, thank you for taking the time to read, and possibly offer comment.

First of all, the only noticeable side effect of this issue is that my coaxial lines are not able to hold the prober connectivity for more than a few hours because apparently voltage is building up inside their splitters? The internet connection and the tv on-demand connections do not work due to this. Comcast sent many techs to the house to finally arrive at this conclusion. At which point I called an electrician. He checked the grounding of the house, which at the time was the only thing comcast told me to ask for. $125 later, I could say that everything was properly grounded. The electrician did notice voltage mysteriously coming from my outlets and being emitted from the back of all comcast equipment (not isolated to one piece of equipment, and this is withOUT the comcast inbound line connected. So, I get two more electricians out, and they agree something is going on, but they cannot tell me why, or whether it's a hazard (they do not believe it is). Here is the description from the last electrician who was there:

We found 8 volts present on our multi-meter between the ground outlet and the back of the router box, we found the same 8 volts between neutral and the back of the box. The Router is two prone with no ground. We found the same 8 volt issue with the lamp, also a two prong lamp with a metal base. When we grounded the back of the box to the buildings ground through the water pipe the voltage reading went to 0 – on the router and the lamp. When we put an inline amp probe between the rear of the router and the neutral we found no current.
We found the neutral and ground bonded in the panel and to the water system - we recommended adding a ground rod, but we do not believe the lack of a ground rod is causing the issue.
We looked for loose neutrals and loose wiring and we did not find any, we did check and tighten your panel connections.
We believe the voltage is being induced rather than being a direct short, that’s just a theory.

Anyone got any ideas?

A little more info might lead us to the problem. Were both the router box and the lamp plugged into the outlet when the measurements were made? Did the TV guys try a different router? Was anything hardwired to the router (TV, PC, etc...) during the tests?

This forum is oriented towards professionals.

You are not using trade terms.

Your missive doesn't quite spell out your problem -- other than your system doesn't work correctly.

I'd advise throwing the problem back upon your vendor.

Your problem is not electrical, it is within the cable tv system in your home. Get Comcast back out, have them check ALL of the connectors in the house, on the service drop and at the tap. Look for loose fittings, poorly installed connectors, corrosion between the center conductor and shield and damaged cables. Have them replace anything that is not Comcast approved. Make sure all of the connectors are tight-- a little beyond finger tight (except for the fittings on modems, cable boxes and tv's which need to be finger tight only).

Even though the electricians did not find a "loose" neutral I am very suspicious of the integrity of his grounded conductor between the house and the transformer.

thanks for the responses. it's not a comcast issue. We unplugged all comcast lines. Just any piece of equipment (not necessarily a comcast box), and the same 8 volts is read. I assume if this reputable electric company couldn't figure it out, I'm sure my layman's approach to describing the problem here isn't exactly helpful. but thought i would give it a shot. the "issue" was occuring all over the house, not necessarily isolated to one circuit or one piece of equipment.

Anybody check the earth ground connection at the demark??

I'm the writer of the www.NoShockZone.org blog on electrical safety as well as the moderator of the AC Power & Grounding Forum on ProSoundWeb.com magazine, so I'm very interested in what's going on with your grounding problem. At first blush this appears to be an open neutral feeding your house, but not all the pieces fit. Please email your phone number to mike@noshockzone.org so we can discuss this a bit.

Is this an analog meter or a digital meter?

Digital?
Put a 200k resistor across the leads and try it again (the load of a 20,000 ohm/volt analog meter on the 10v scale)
If your voltage goes away, you are chasing a ghost.

An open neutral, usually presents itself as L-N voltages that are not equal.

It is quite common to be able to measure a voltage between a neutral and a ground. This has to do with the voltage drop caused by the load on the circuit.

I am not sure what problem the OP is trying to mitigate.