Ground Loop
I recently moved and connected my new Cox Contour DVR to an audio receiver and TV. There was a pretty bad hum so I inserted an isolation transformer between the cable feed and the DVR, which eliminated the hum. I measured the voltage between the outside of the cable connector and safety ground with a cheap VOM and found 200 mVAC.
Does this voltage indicate that the cable is improperly grounded?
If the cable were to be bonded to the house neutral with 3/0AWG, would this likely eliminate the need for the isolation transformer?
Whether it would eliminate the hum or not, should I have it done?
Does the cable company have any obligation to do it in order to comply with regulations?
Bob Simon
New Orleans
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