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Posted by phantom2 (My Page) on
Fri, Aug 20, 10 at 14:23

Here's my situation: I am getting a hum on my home theater speakers, when I unplug the cable input to my tivo box, the hum goes away. I assume this to be a ground loop issue. The cables for CATV appear to be attached to grounding blocks which are connected to a copper wire which runs back into my house and is clamped to what looks to be metal conduit coming out of the panel. Another piece of what looks like metal conduit comes out of the side of the panel, goes near the floor and is clamped to what appears to be a grounding rod coming out of the basement floor. Both the clamps and the grounding rod are very rusty.

1. Is it possible for this grounding rod to be serving any grounding purpose at all if it and the clamps are so rusty? And as a consequence, could this be causing the hum in my speakers?
2. If a new rod needs to be installed, it seems as though it should be done outside the house... yes?
3. Does it matter where the grounding wire from a new rod attaches to the panel?
4. Anything else I should consider?


Follow-Up Postings:

RE: Grounding

Cable TV, Satellite dishes and other foreign electrical systems must be bonded to the house grounding electrode system.

The way you desribe it has been done is acceptable and appears to be proper.

But it remains questionable whether or not grounding has anything to to with your problem.

I would look instead to see if you have any places where your cable has been run next to or in contact with house wiring. Electromagnetic interference from the power cable could be creating the noise in the cable conductor you are hearing.

Make sure also that your TV and other equipment are not sharing a circuit with computer or other office equipment, which could create harmonic currents that can also create interference if run with other electronic equipment.

RE: Grounding

Try lifting the ground at the ac outlet at the wall. Buy a ground lifter

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