Knob + tube and non-contact voltage tester false positives - Electrician Talk - Professional Electrical Contractors Forum
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Old 08-20-2018, 05:06 PM   #1
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Default Knob + tube and non-contact voltage tester false positives

Hi all --


DIY'er here with a decent amount of experience (when it comes to the box, never fear -- I always call a pro).



Question: We're in the process of removing the last K+T circuit from the house. I've been trying to use a non-contact voltage tester to see which of the lines are live and not. The non-contact gives a ton of false positives -- it even beeps on lengths of K+T wire that are cut at both ends.



One example: K+T in an outlet box that reads as dead with my contact voltage tester. After testing it with the tester, I even grabbed it with my bare hand -- nothing. But then I touch the non-contact tester to it and it goes crazy.



I even find that it I touch the non-contact tester to a K+T line, it will go off in some spots and not in others.



It is completely useless? What's it trying to tell me?



Thanks!
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Old 08-20-2018, 05:34 PM   #2
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Hi all --


What's it trying to tell me?



Thanks!
that you should go buy a multimeter.


IBTL
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Old 08-20-2018, 05:36 PM   #3
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I did. The multimeter shows very low voltage -- which makes me think this is "phantom" voltage.
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Old 08-20-2018, 05:51 PM   #4
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I did. The multimeter shows very low voltage -- which makes me think this is "phantom" voltage.


That's why the tracer is beeping
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Old 08-20-2018, 05:55 PM   #5
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It is completely useless? What's it trying to tell me?



Thanks!
Not useless, and it's telling you it's doing it's job.

They have their purpose, but never trust one before grabbing wires, always use a meter.
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Old 08-20-2018, 06:43 PM   #6
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And k & t is generally wired using switched neutrals, part of the reason why you should hire us professionals...
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Old 08-20-2018, 06:48 PM   #7
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And k & t is generally wired using switched neutrals, part of the reason why you should hire us professionals...
But he is a qualified DIYer!

He even said so!

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Old 08-20-2018, 07:08 PM   #8
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This site is for professional electricians.

DIYChatroom... or some such.

IBTL

BTW K&T is infamous for killing DIYers.
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Old 08-20-2018, 07:13 PM   #9
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This site is for professional electricians.

DIYChatroom... or some such.

IBTL

BTW K&T is infamous for killing DIYers.
https://www.diychatroom.com/
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Old 08-20-2018, 07:22 PM   #10
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diychatroom

Thanks. And thanks for not being a condescending ass, like some of these folks.
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Old 08-20-2018, 07:28 PM   #11
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I believe the signup page has that link listed.
You know.....when it asks if your an electrician or not when you sign up!

We are a bit condescending, but we get alot of dumbasses coming through that are DIYers.

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Old 08-20-2018, 07:59 PM   #12
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IBTL for 2
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Old 08-20-2018, 08:02 PM   #13
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Quote:
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Thanks. And thanks for not being a condescending ass, like some of these folks.
WoW, that's a harsh statement.


I think you hurt some feelings.


I'm going to my safe place,,,, the DYI dry wallers site.
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Old 08-20-2018, 08:09 PM   #14
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WoW, that's a harsh statement.


I think you hurt some feelings.


I'm going to my safe place,,,, the DYI dry wallers site.
That's good. Because, if you wonder into the PlumbingZone.com, they'll just flush you immediately.
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Old 08-20-2018, 08:19 PM   #15
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For a brief moment, I thought this was a thread by the renown forum member MTW...boy is that not the case! Can I somehow obtain a refund?
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Old 08-20-2018, 08:22 PM   #16
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