I have electricty present in my Comcast cable line, which I had checked by a tech. He claims that the electricity is coming from a component in my setup. I have spent hours trying to solve this problem with no results. All power outlets are clean and correctly grounded.


Here is what happens:
*The cable line is disconnected from the cable box. Touching the line while having your other hand on the cable box gives you a good tingle and tapping the tip of the line to the metal part of the box produces a tiny spark / arc.

*Shut off all power to the entertainment center stops the cable line from having volts coming through it.

*If the VCR / DVD combo is just connected to the cable box you get the same results as the first bullet, same goes for just the TV.

*I replaced the VCR / DVD player thinking it was the cause, but did not solve the problem.

*The power in the house is clean. All outlets and power strips were checked by Comcast [and me].

*Only standard gold plate RCA cable connect the components as follows:

1. Cable Box to VCR

2. VCR to A/V Selector

3. A/V Selector to in Sound System

4. Sound System has Video Out to TV



Cable line is clean from the basement. As long as the cable box is connected to one component in the setup, the electricity is created as described in the first bullet. Does not matter if its just the TV, just the DVD / VCR combo, or just the sound system. I have even elminated the A/V selector.

I still think the electricity is in the line and coming to this setup because the line is the shortest in the house. I have the old school Comcast Digital Phone service from the MediaOne days, 3 cable boxes in the house, Internet, and a signal booster in the basement.



Thoughts?

Where is the cable input grounded? Is it remote from the main house ground? That could account for the potential difference. I had a similar problem and it took 2 service calls from my cable co. (Charter) before I convinced the tech to relocate the input cable ground and tied it to the main ground. When he did, it solved the problem and it took only 10 minutes.

Let me second Kal. Your cable entry should have a grounding block that is connected directly to your electrical grounding rod (best) or to the panel.

Electrical devices in home use are allowed (although IMO is should not happen) to have as much as a 30 or so volts at the chassis. However if the hardware chassis and the cable are at the same ground, then no current will flow. So either your cable is not correctly grounded or the branch circuit is not correctly grounded.

Poor grounding at the cable entrance is the usual problem.

I agree with the previous two posts. However, you should trace the lines all the way from the pole to where you develop a problem. In other words, go outside to where the cable first comes into the house. Is there a shock/jolt there? If not, go further into the house. Is there a shock/jolt at the next coupling/connection? If so, then that's the culprit. If not, then continue following the cable until you do get a shock/jolt. Whatever is between were you are now and where you previously were is the problem.

...tapping the tip of the line to the metal part of the box produces a tiny spark / arc.

I just reread your OP and you seem to say that the spark jumps to the center (ungrounded ) coax conductor and not the outer (shield) conductor. That suggests that the shield is ungrounded or at the same ground as your equipment.

Have you measured the voltage at the cable, center to shield and center to ground. Have you measured the voltage from each of you components from chassis to ground? With what results?

I just reread your OP and you seem to say that the spark jumps to the center (ungrounded ) coax conductor and not the outer (shield) conductor. That suggests that the shield is ungrounded or at the same ground as your equipment.

Have you measured the voltage at the cable, center to shield and center to ground. Have you measured the voltage from each of you components from chassis to ground? With what results?

Comcast checked my outlets and said they are correctly grounded. He could not find any voltage in the basement coming into the house. He used a voltage meter on the cable line and it registered 1amp off and on. Testing my A/C cables with the voltage meter registered nothing.

I will check the grounds outside. BTW, the park comes from the copper middle of the cable line.

Let's assume that the cable grounding block is correctly grounded to your electrical grounding point. CC techs in my area seem to check it routinely.

So the question remains, from where is the tingly-sparking voltage when you connect the cable? You should pursue this as you may have a dangerous situation.

I suggest that you borrow a digital multi-meter (DMM)or buy one. Avoid the $6 model with a needle type meter.

Read the instructions first. Then double check the cable guy's work. Set the meter to AC and a range of 200 volts.

At the outlet(s) you use your gear, check for ~116 to 120v between the hot and "neutral" (the two vertical pin slots), and between the hot pin slot and the rounded ground pin hole. There should be 0 v between the neutral pin hole and the ground pin hole. If you are using a DMM the reading may alternate between 0 and 1 and that's OK

Disconnect the cable from your set top box. Check to see if any there is any AC voltage between the center copper wire of the cable coax and the grounding pin hole in the outlet you just checked. The reading should be 0. . Also check for voltage between the center copper wire and the outer (screw on) connector.

Use care to ensure that only the probes (and not you) are connected to ground.

None? Then-

Beginning with the set top box, measure the AC voltage between the chassis and the ground pin hole in your wall outlet. Disconnect the CC cable and all audio/video cables. Plug in the devices power cord but leave it turned off. You will need to place the probe on bare metal; this might be the metal plate on the bottom or back or a sheet metal screw that goes into the chassis. It should be 0 volts. Repeat the test after turning the device on. The voltage should still be 0.

If you find > about 30 volts between the chassis and the power ground on any device you have your culprit and a potentially dangerous situation. Let us know what you find.

Let's assume that the cable grounding block is correctly grounded to your electrical grounding point. CC techs in my area seem to check it routinely.

So the question remains, from where is the tingly-sparking voltage when you connect the cable? You should pursue this as you may have a dangerous situation.

I suggest that you borrow a digital multi-meter (DMM)or buy one. Avoid the $6 model with a needle type meter.

Read the instructions first. Then double check the cable guy's work. Set the meter to AC and a range of 200 volts.

At the outlet(s) you use your gear, check for ~116 to 120v between the hot and "neutral" (the two vertical pin slots), and between the hot pin slot and the rounded ground pin hole. There should be 0 v between the neutral pin hole and the ground pin hole. If you are using a DMM the reading may alternate between 0 and 1 and that's OK

Disconnect the cable from your set top box. Check to see if any there is any AC voltage between the center copper wire of the cable coax and the grounding pin hole in the outlet you just checked. The reading should be 0. . Also check for voltage between the center copper wire and the outer (screw on) connector.

Use care to ensure that only the probes (and not you) are connected to ground.

None? Then-

Beginning with the set top box, measure the AC voltage between the chassis and the ground pin hole in your wall outlet. Disconnect the CC cable and all audio/video cables. Plug in the devices power cord but leave it turned off. You will need to place the probe on bare metal; this might be the metal plate on the bottom or back or a sheet metal screw that goes into the chassis. It should be 0 volts. Repeat the test after turning the device on. The voltage should still be 0.

If you find > about 30 volts between the chassis and the power ground on any device you have your culprit and a potentially dangerous situation. Let us know what you find.

Can I grab one of these meters at Radio Shack?

This does not seem to impact the function of my system at all. I believe this has been going on for awhile now...


Thanks for your help. I have no idea where to turn on this and I plan on trying this as soon as I get the DMM.

Radio Shack has them, and they work well.

Results:


1. Between Center Copper Wire [Cable Line] & Cable Box Chassis: 30 Volts
-- The 30 volts only happens when the cable box is connected to the A/V cables to the rest of the system.
2. Between Outter Screw Connector [Cable Line] & Cable Box Chassis: 30 Volts
3. Between Neutral Pin & Ground Pin Hole: 0 Volts
4. Between Hot Pin & Ground Pin Hole: 122 Volts
5. Between Hot Pin & Neutral Pin Holes: 122 Volts
6. Between Cable Line & Ground Pin Hole [Outlet]: 0 Volts


Equipment Outlet Ground Pin to:
1. TV - 6 Volts (On and Off)
2. Cable Box -7 Volts when just plugged into the wall.
3. Audio System: (2 Volts Disconnected from TV / 15 Volts Connected to TV)
4. DVD VCR Combo - 0 Volts

Looks like every component is putting out something...

What does this mean? I touched the probe to the RCA (A/V) inputs on each of the components once disconnected from the other components.

Any thoughts on this with the above readings? As of today I noticed the following:


I picked up an AC Voltage Detector today with a new DMM. If I disconnect my cable line from my cable box then the AC Detector goes nuts if it is near any of my equipment. As soon as I reconnect the cable line to the cable box it stops detecting the AC voltage...

It is like the equipment is grounding via the cable line. If I touch any of the equipment with my hand then the detector also stops.

We may need a good tech to drop in here, but here are my first impressions. 30 volts is safe and allowable, and if you have no hum or video interference issues you could stop now.

I think that your measurements implicate the cable box as the source of the voltage. There are two things you might do. First post in a forum specific to your make and model and ask if anyone else has measured 30 volts between the box and the cable ground or center conductor. The second thing you might do is get another box. In my Comcast area it would be easy; I would just take the old one in and exchange it.

I just measured the voltage between my Moto3412 and ground and my Pace Vegas(?) and ground; both read zero. One of my TVs has just over volt to ground and the other is zero.



3. Between Neutral Pin & Ground Pin Hole: 0 Volts
4. Between Hot Pin & Ground Pin Hole: 122 Volts
5. Between Hot Pin & Neutral Pin Holes: 122 Volts
6. Between Cable Line & Ground Pin Hole [Outlet]: 0 Volts

Was #6 the from the cable Co's coax shield to ground or the center conductor to ground or both? If both then everything is as it should be.



1. Between Center Copper Wire [Cable Line] & Cable Box Chassis: 30 Volts
-- The 30 volts only happens when the cable box is connected to the A/V cables to the rest of the system.

Go to next.

2. Between Outter Screw Connector [Cable Line] & Cable Box Chassis: 30 Volts
If this measurement was taken with no other device connected to the cable box, then the cable box chassis is 30 volts above the cable shield or the cable is 30 volts above the chassis. Because you did not read any voltage between the cable shield and the power outlet ground, the cable box is the source of the voltage.


Equipment Outlet Ground Pin to:
1. TV - 6 Volts (On and Off)
2. Cable Box -7 Volts when just plugged into the wall.
3. Audio System: (2 Volts Disconnected from TV / 15 Volts Connected to TV)
4. DVD VCR Combo - 0 Volts

Nothing bad-Nothing good-as long as you are not having hum or video interference.

If this measurement was taken with no other device connected to the cable box, then the cable box chassis is 30 volts above the cable shield or the cable is 30 volts above the chassis. Because you did not read any voltage between the cable shield and the power outlet ground, the cable box is the source of the voltage.



The 30 VOLTS at the Cable Box Chassis is while it is connected to the setup as pictured below. It only reads 6 Volts when connected JUST to the wall outlet with no other connections.

http://home.comcast.net/~computek20/tv.gif

Have you eliminated the power/signal booster?
Is the AV selector a powered device?

Have you eliminated the power/signal booster?
Is the AV selector a powered device?

The A/C Selector is not a powered device. Comcast eliminated the power / signal booster.

Any other suggestions on this issue? My equipment has shown no signs of any issues. The DVR dieing must have been a bad DVR. The current one has been working fine for several weeks now.

I have no video or audio interference.

Just an update. I have yet to find a solution to this problem. As of now the new DVR is working perfectly and I am having no equipment issues.

However, it still bothers me that this is happening.

You're saying you have three TVs? Did you disconnect the other cable boxes from the cable before measuring? The problem could possibly be in another cable box or TV, and transmit itself through the cable.

You're saying you have three TVs? Did you disconnect the other cable boxes from the cable before measuring? The problem could possibly be in another cable box or TV, and transmit itself through the cable.

Comcast tried this for me. I am fairly certain it is not the power because I have tried plugging the equipment into different outlets in the house via a extension cord. Same results. No other setup in the house is having this problem.

I just installed a MONSTER PowerCenter with a Stage 1 v2.0 Power Filter.
(Here is the PowerCenter: http://www.royaldiscount.com/moht8po.html)

Same results are stated above. The only other difference is now the cable line from the basement runs into the PowerCenter then to the cable box. Yet, I can still measure volts from the various places described above.

Basically, the cable line is surge protected and it was not before.

None of my equipment has failed nor am I noticing interference. Is it possible these conditions are normal?

Was reading this thread and had a stupid question for you. When they hooked you up to the digital phone service did they physically disconnect your house from ma-bell?

Was reading this thread and had a stupid question for you. When they hooked you up to the digital phone service did they physically disconnect your house from ma-bell?

I have no idea. I would assume they did. Why would that matter?

Ok, so im convinced the volts are coming from equipment in my setup.

I disconnected my cable line from the rest of the house in the basement. I got the same results. So the electricity is not coming from the cable system.

The volts from the equipment just likes to ground out via the cable line.

Plugged my entire setup into an outlet in a different part of the house, via an extension cord, and got the same results (the TV system on that outlet does not do this).

So based on this, I believe equipment in my setup is causing this issue. How do I narrow it down based on the results above?

EDIT: My desktop computer has been plugged into this same outlet as the TV for years. I imagine if the power in my house was bad my computer would be having issues?

Thanks again.


Fluke Meter Results:



1. Between Center Copper Wire [Cable Line] & Cable Box Chassis: 30 Volts
-- The 30 volts only happens when the cable box is connected to the A/V cables to the rest of the system.
2. Between Outter Screw Connector [Cable Line] & Cable Box Chassis: 30 Volts
3. Between Neutral Pin & Ground Pin Hole of Outlet: 0 Volts
4. Between Hot Pin & Ground Pin Hole of Outlet: 122 Volts
5. Between Hot Pin & Neutral Pin Holes of Outlet: 122 Volts
6. Between Cable Line & Ground Pin Hole [Outlet]: 0 Volts


Equipment // Outlet Ground Pin to:
1. TV - 6 Volts (On and Off)
2. Cable Box -7 Volts when just plugged into the wall.
3. Audio System: (2 Volts Disconnected from TV / 15 Volts Connected to TV)
4. DVD VCR Combo - 0 Volts

Is all of your equipment plugged into the same circuit? If not get a power strip and plug them into that. Unplug your cable from any other equipment not plugged into the power strip.

Retest your voltages.

Is all of your equipment plugged into the same circuit? If not get a power strip and plug them into that. Unplug your cable from any other equipment not plugged into the power strip.

Retest your voltages.



Could you clarify? I am a bit confused.

All equipment are on the same circuit plugged into the same surge protector.


I have four outlet circuit in this room. Plugged into it is:

1. Computer on Outlet 1
2. Entertainment System on Outlet 2
3. Phone Chargers and so forth on Outlet 3

Every outlet has its own surge protector.