Electrical Backfeed on cable tv coaxial

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  #1  
Old 12-14-04, 03:16 PM
edemuth1
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Question Electrical Backfeed on cable tv coaxial

I had the cable TV installer at my house. He put in a splitter box on the outside and stated that 3 of the 5 coaxial cables next to the outside box(serving different rooms) were backfeeding 47 to 50 volts to the main coax serving the house (he thinks the coax is serving as a ground) Anyone encountered this problem before??

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Old 12-14-04, 05:05 PM
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Did he connect his ground to the electrcial system ground or pound in his own ground rod for the cable?
 
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Old 12-14-04, 05:59 PM
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This usually happens because most televisions are ungrounded. But please answer Joe's question. Exactly how did the installer ground the coax?
 
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Old 12-15-04, 02:20 PM
edemuth1
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The installer used an existing coaxial cable ground that is connected to the electrical service mast in turn terminating in the electrical ground rod
 
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Old 12-17-04, 09:44 PM
SkyKing
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You are not required to have a seperate ground for tv or phone service. It just isn't neccessary. What is happnening is, your tv's will backfeed the power onto the circuit. It really isn't any big deal. I have been shocked multiple times by this small ammount of voltage. Touch the stinger with one hand and hold the splitter, you can feel it if the tv is on. Many of the "bigger" tv's have this "problem". If you see little sparkles and stars on your tv picture, then there are parasitic voltages from an electrical system seeping onto your current system. I'd assume it's the TV.
 
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Old 12-18-04, 07:03 AM
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Skyking,
You will find that Article 800 (Communications circuits) and 810 (Radio and television equipment) require bonding of the incoming with the grounding electrode system.
 
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Old 12-18-04, 08:48 AM
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Originally Posted by SkyKing
You are not required to have a seperate ground for tv or phone service. It just isn't neccessary.

You MUST not have separate ground rod on the cable or phone system. That is one thing that can create this problem.
If the cable is grounded to the electrical system then you should not have any potential on the ground sheilding. It is technically not possible. You must have an open gound somewhere on the cable system or an open neutral in your service panel..
 
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