Stray Voltage Problem?

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chevyx92

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VA BCH, VA
Long story short. Cable guy gets a shock on receiver in my house. I test between metal case of receiver and the ground prong of an outlet and read 48 volts (that's with the incoming cable line disconnected from the receiver). If the cable line is left attached to the receiver then the voltage goes to ZERO (which I understand because it's grounded at service point). I then tested between the metal case of my DVD player and ground prong on outlet and read 27 volts. I tested between the metal case of my VCR and ground prong on outlet and read 27 volts. I then plugged these devices into a different circuit on a different phase and got the same readings. Then I took the DVD player and plugged it into outlets all over the house, on different circuits and phases and got the same results(voltage between metal case and ground prong on outlet). Voltages at various outlets move from 121.2 volts to 123.7 volts.

This had me thinking there was a neutral problem at my service. I installed (2) new grounds rods and new #6 wire from rods to neutral bar in main panel and yes the bonding jumper is installed and tight. This didn't change anything in the house. Water piping is plastic, so no cold water ground.

I called out POCO and they tested their stuff and said everything was good.

I'm not sure what else to test or how to fix this but I believe the problem is on POCO side not in my house. What do you professionals think? Did I miss something in my troubleshooting?
 
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Is Cable service bonded to electric service, sounds like it is not.

That said there still is voltage rise on a grounded conductor somewhere or on the TV cable for some reason. Maybe place a ground probe out in the yard and measure voltage from both your grounded service conductor as well as from the TV cable. That will at least tell you which one is at/closer to ground potential. (they both may have some voltage on them)
 
chevyx92 said:
Long story short. Cable guy gets a shock on receiver in my house. I test between metal case of receiver and the ground prong of an outlet and read 48 volts (that's with the incoming cable line disconnected from the receiver). If the cable line is left attached to the receiver then the voltage goes to ZERO (which I understand because it's grounded at service point). I then tested between the metal case of my DVD player and ground prong on outlet and read 27 volts. I tested between the metal case of my VCR and ground prong on outlet and read 27 volts. I then plugged these devices into a different circuit on a different phase and got the same readings. Then I took the DVD player and plugged it into outlets all over the house, on different circuits and phases and got the same results(voltage between metal case and ground prong on outlet). Voltages at various outlets move from 121.2 volts to 123.7 volts.

This had me thinking there was a neutral problem at my service. I installed (2) new grounds rods and new #6 wire from rods to neutral bar in main panel and yes the bonding jumper is installed and tight. This didn't change anything in the house. Water piping is plastic, so no cold water ground.

I called out POCO and they tested their stuff and said everything was good.

I'm not sure what else to test or how to fix this but I believe the problem is on POCO side not in my house. What do you professionals think? Did I miss something in my troubleshooting?
Click to expand...

kwired said:
Is Cable service bonded to electric service, sounds like it is not.

That said there still is voltage rise on a grounded conductor somewhere or on the TV cable for some reason. Maybe place a ground probe out in the yard and measure voltage from both your grounded service conductor as well as from the TV cable. That will at least tell you which one is at/closer to ground potential. (they both may have some voltage on them)
Click to expand...
I may have been barking up wrong tree if cable isn't connected to the cable box. Does cable box have an EGC in the power supply cord?
 
kwired said:
I may have been barking up wrong tree if cable isn't connected to the cable box. Does cable box have an EGC in the power supply cord?
Click to expand...

No EGC on their cord. Same as for DVD player and VCR. Pretty much any two wire cord plugged into the outlet and then measuring voltage from metal case to ground you anywhere between 27-48 volts.
 
With ungrounded equipment and voltage present on that equipment, it sounds like a problem with the equipment. Like a ground fault. Figure out a way to run an external ground.
 
chevyx92 said:
Long story short. Cable guy gets a shock on receiver in my house. I test between metal case of receiver and the ground prong of an outlet and read 48 volts (that's with the incoming cable line disconnected from the receiver). If the cable line is left attached to the receiver then the voltage goes to ZERO...
Click to expand...

And a two wire line cord.

That's all I need to know so stop right there. What meter are you using? Was the cable box connected to the TV or not?

-Hal
 
When you changed out the service did you reground the cable? Sometimes they are connected to the front of the panel, but that's what 250.94 is supposed to take care of.
 
chevyx92 said:
No it was not connected. Fluke clamp on/meter.
Click to expand...

Is the receptacle wired correctly- did you check the receptacle for proper polarity?

Assuming all is OK, the box was just sitting there with only its 2-wire line cord plugged in, correct?

You don't say which Fluke but likely your meter has a high impedance input and is indicating a phantom voltage. Load it down a little with like a 15W light bulb in a pigtail socket connected across your test leads. Betcha it goes away.

Or just ask tell the cable guy (after he recovers from his shock) to replace your box. It is possible that it's defective and there is abnormal leakage to the metal case. If you still see the voltage with another box then you are seeing a phantom voltage.

ETA: I see that you mention somewhere else that other devices also show the same problem. Phantom voltage because of the meter you are using.

-Hal
 
hbiss said:
Is the receptacle wired correctly- did you check the receptacle for proper polarity?-Hal
Click to expand...

Yes it is.


hbiss said:
Assuming all is OK, the box was just sitting there with only its 2-wire line cord plugged in, correct?-Hal
Click to expand...

Yes.

hbiss said:
You don't say which Fluke but likely your meter has a high impedance input and is indicating a phantom voltage. Load it down a little with like a 15W light bulb in a pigtail socket connected across your test leads. Betcha it goes away.
Click to expand...

Hmmm???


hbiss said:
Or just ask tell the cable guy (after he recovers from his shock) to replace your box. It is possible that it's defective and there is abnormal leakage to the metal case. If you still see the voltage with another box then you are seeing a phantom voltage. Hal
Click to expand...

I guess I could.

hbiss said:
ETA: I see that you mention somewhere else that other devices also show the same problem. Phantom voltage because of the meter you are using.

-Hal
Click to expand...

If it's phantom voltage, how did he get shocked? You know what, I will try using a Stray Voltage Eliminator Adapter and see what happens. Will update you later.
 
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