I just don't know...

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1793

1793

Senior Member
Location
Louisville, Kentucky
Occupation
Inspector
Not sure where to post this one...

I went on a Service call today and I walked into something I hate to admit but I'm stumped.

Customer has a power strip plugged into 120v 15a receptacle, TV, Wii, DVD player, Cable Box and PlayStation 2.

When the TV coax cable touches the TV there is a HUGE arc. Customer told me they have "smoked" two TV,s within a two day period. I was told that when everything was plugged in the lights would dim.

The HO unplugged the power strip and moved to another receptacle and the problem is solved.

I asked to hook up everything with the exception of the NEW TV. When I touched the Coax to the TV, not plugged in, I got a HUGE arc. I then disconnected everything and started to connected things one at a time and everything seem to be fine until the PS2 was connected.

I then unplugged the Power Strip and moved it to another receptacle turned on everything, except TV, and all was good.

I'm at a loss and hope someone could share some insight.
 
I will take a stab at it.

Problem with the bonding of the shield on the coax and/or bad neutral out to the utility.

I suspect you will find the coax shield is live.
 
I think bob's right. maybe the coax seems fine on the other plug because its on the phase that is energizing the shield ?
 
I did look outside at the Cable Connections and it was a mess. The Cable folks ran a new line but it appeared to me that the splice block was NOT grounded. I think it should be but is it my responsibility or the Cable Company?
 
In the future I'ld suggest getting out a meter to look at this stuff rather than stick wires together to see if they arc and bark!!
 
1793 said:
I did look outside at the Cable Connections and it was a mess. The Cable folks ran a new line but it appeared to me that the splice block was NOT grounded. I think it should be but is it my responsibility or the Cable Company?
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Did you open there here point of demark? Mine has a change over spitter to aerial and a point of attatachment for a ground wire and on that wire is the tag, "Do not disconnect".

;)
 
Neat and workmanlike manner is something most of the cable guys don't seem very familiar with. If it is a grounding issue the cable company will probably charge the HO to remedy it. Better the coin goes in your pocket.:smile:
 
Clearly, there are points that should be at the same potential, but aren't. I agree with the other guys: sounds like a neutral issue.

Someone who knows what they're looking for needs to get in there are find where the problem is. Too soon to blame one device.
 
iwire said:
I will take a stab at it.

Problem with the bonding of the shield on the coax and/or bad neutral out to the utility.

I suspect you will find the coax shield is live.
Click to expand...
I'm going to aggree - even say that it is possible that the shield of the coax is carrying the of the house to the neighbors. Or vise versa. I would take readings on the coax to the outlet(s) with a DMM - (Not a wiggy!)

The HO unplugged the power strip and moved to another receptacle and the problem is solved.
Click to expand...
Check this out too. Both the outlet, and strip - especially if it one of those with a surge connection for the coax and phone on it...
 
I ran into a problem like that once. It was in a rental near campus filled with college students. it turned out that that the homes original wiring was nm with out a ground, and a remodel done recently was nmb with a ground merely extending an original ckt. the new and old wiring were in the same junction box where they were both protected by a gfi. but the ground in the newer romex was touching one of the hot terminals causing the ground to be hot on the recps down stream on the newer nmb. thru all of the assorted equipment plugged into those recps the coax from the equipment to the tv had a 120 volts on it, and would give off quite a spark when you tried to plug it into the tv.
 
Shut off the service attatch all the missing grounds to the cable splitters for starters. This will eliminate the cable shields from destroying equipment. Hey where is the anti grounding people now?? Chime in at any time. You have an open neutral somewhere and thank god the cable ground is carrying it for now or you would have a fire.
 
thats a wierd situation. i would put my meter to the coaxial and a ground to see what kind of voltage is coming out of it first. what kind of voltage does cable tv run on? cross reference it with regular voltage ie. 120 volt to see what could be causing it , the house power, or the cable power. and then go from there.
 
I had a similar problem years ago. I discovered the coax cable was drawing 7 amps from the house. The cable company did not believe me. They sent out two engineers and two service trucks. I showed them with the main shut of thier cables were drawing power from the house. The had a private conference for ten minutes then came back and asked if they could borrow my amprobe and how to best find the source of the problem. I loaned them the probe and gave them instructions. They found a house a block away with an open neutral on its service. They notified the owners of the problem and disconnected cable service and the problem ended.
 
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