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Old 01-01-2013, 01:00 PM   #16
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Voltage on my ground leg


Quote:
Originally Posted by stubie View Post
Is the receptacle your testing on the knob and tube wiring ?

Is it a 2 prong receptacle or 3 prong?

Is your new tv a 3 prong plug or 2 prong ?

If the receptacle is two prong and your testing to the neutral then it could be wired reverse of normal ..ie.. hot to the neutral side and neutral on the hot side. This would explain the voltage reading to the ground of the HDMI when you test.

If it is 3 prong and a bootleg ground was installed and the receptacle is wired reverse .. if you plug a 3 prong plug into it you would energize the the ground of the tv which would travel to the hdmi cable.

It is very common to see knob and tube wiring reversed on receptacles and in some cases this can cause problems.
TV and recept are 3 prong. There is voltage between hot and neutral, ground and neutral, but not ground to hot which tells me both hot and ground are energized. I hope to find out the "why" tomorrow when I have more time.

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Old 01-01-2013, 01:08 PM   #17
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Voltage on my ground leg


I agree, Jim. I'm gonna remedy that with a romex run that completely bypasses that k&t. In the spring, I'm having all the k&t removed and the fuse box upgraded to a breaker box.
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Old 01-01-2013, 01:18 PM   #18
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Voltage on my ground leg


Quote:
Originally Posted by patrickmcdiver

TV and recept are 3 prong. There is voltage between hot and neutral, ground and neutral, but not ground to hot which tells me both hot and ground are energized. I hope to find out the "why" tomorrow when I have more time.
How do you know that you don't simply have a case of reversed polarity?
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Old 01-01-2013, 01:36 PM   #19
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Voltage on my ground leg


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How do you know that you don't simply have a case of reversed polarity?
Good point. In order for it to read that way in a reversed-polarity case, the ground would have to be good. Based on the whole scenario that the OP describes, I'm assuming that the ground is not good. However, we don't know that for sure. It certainly wouldn't be the first time that something got connected reversed on a K&T circuit.
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Old 01-01-2013, 03:01 PM   #20
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Voltage on my ground leg


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Originally Posted by k_buz View Post
How do you know that you don't simply have a case of reversed polarity?
The incident with the TV indicates that the ground pin is hot with respect to the actual earth, not just that hot and ground are reversed at the receptacle. The biggest clue as to what happened is that the grounded romex is connected only to ungrounded K&T. It seems the romex ground is bonded to the wrong K&T conductor. It shouldn't have been bonded to either - the circuit should have been run ungrounded (if it was even legal to extend K&T at the time it was done).
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Old 01-01-2013, 03:12 PM   #21
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Voltage on my ground leg


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The incident with the TV indicates that the ground pin is hot with respect to the actual earth, not just that hot and ground are reversed at the receptacle. The biggest clue as to what happened is that the grounded romex is connected only to ungrounded K&T. It seems the romex ground is bonded to the wrong K&T conductor. It shouldn't have been bonded to either - the circuit should have been run ungrounded (if it was even legal to extend K&T at the time it was done).
It really doesn't matter too much as I don't believe this was an actual problem. The OP states "PLEASE help" as it is an urgent situation. He then changes the wiring method used, rechecks voltages, goes into the attic to find romex spliced with knob and tube, then doesn't have time to fix it.

I could be wrong, but keep in mind that in order for the bootleg ground to be energized, the bare ground would have to be tied into the hot black...something 99% of the average DIYer knows isn't right. The reason I am saying that the ground would be tied into the same splice as the black is that the OP made no mention of the white being hot...something which I believe they would have posted.
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Old 01-01-2013, 03:30 PM   #22
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Perhaps both the neutral and ground are BOTH tied incorrectley to the K&T hot and the neutral to the K&T hot. Would that not give the readings in post #7?
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Old 01-01-2013, 03:36 PM   #23
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Perhaps both the neutral and ground are BOTH tied incorrectley to the K&T hot and the neutral to the K&T hot. Would that not give the readings in post #7?
Not too hard to believe since both conductors of K&T were black.
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Old 01-01-2013, 03:42 PM   #24
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Voltage on my ground leg


Quote:
Originally Posted by brric View Post
Perhaps both the neutral and ground are BOTH tied incorrectley to the K&T hot and the neutral to the K&T hot. Would that not give the readings in post #7?
Quote:
Originally Posted by patrickmcdiver View Post
just double checked. Romex to rept. upstairs. Ground is def hot. Ground to neutral=118vac, hot to neutral=118vac, ground to hot=8vac.

So I wouldn't actually call it BS so much as an error on my part.
No, because there wouldn't be any voltage between white and bare. I believe the OP is stating the voltages between the wires by the color of the wire which would be the common way to denote which wires they were metering.
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Old 01-01-2013, 03:51 PM   #25
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No, because there wouldn't be any voltage between white and bare. I believe the OP is stating the voltages between the wires by the color of the wire which would be the common way to denote which wires they were metering.
Your right, I missed that.
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Old 01-01-2013, 05:56 PM   #26
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Voltage on my ground leg


If the ground is not tied to the K&T (left floating) and there's a ground fault somewhere on the circuit, this would be the result.
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Old 01-01-2013, 11:29 PM   #27
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Voltage on my ground leg


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It really doesn't matter too much as I don't believe this was an actual problem. The OP states "PLEASE help" as it is an urgent situation. He then changes the wiring method used, rechecks voltages, goes into the attic to find romex spliced with knob and tube, then doesn't have time to fix it.

I could be wrong, but keep in mind that in order for the bootleg ground to be energized, the bare ground would have to be tied into the hot black...something 99% of the average DIYer knows isn't right. The reason I am saying that the ground would be tied into the same splice as the black is that the OP made no mention of the white being hot...something which I believe they would have posted.
Busted...I had nothing better to do but post some bogus made up problem. Really! Who is this guy. Anyway, to explain, I hastily posted before doing a little more exploring (I also did some troubleshooting based on suggestions-thank you those who actually had something worth saying). I will continue to explore my completely made up problem tomorrow as I just got off work...on a Holiday! I'm gonna explore the splice and utimately take that out all together as I determine if I have a short somewhere of if someone who owned the house prior to me incorrectly spliced the make believe wires (that could possibly be harmful to the precious 5 year old that shares the upstairs with me). Call THAT made up.
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Old 01-02-2013, 06:33 AM   #28
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Voltage on my ground leg


You would be surprised what we get in here.

Good luck with your problem.
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Old 01-02-2013, 07:19 AM   #29
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Voltage on my ground leg


The first thing I tested was from the ground plug in the recpt to the ground of the cable tv system which is fairly new. That is when I first determined that my ground was "hot". The coaxial cable, nor the HDMI cord shocked me so I am assuming its the ground in the electrical system that is hot.
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Old 01-02-2013, 12:06 PM   #30
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Voltage on my ground leg


Problem discovered and solved. There was a short one of the outlet boxes and since there was no return path for ground, it just stayed on the ground leg. Thanks for your help

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