voltage detector problem

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  #1  
Old 09-18-09, 06:04 AM
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voltage detector problem

I have a pen style voltage detector. The type you use by placing it on a wire or in an outlet and it will detect the presence of voltage by lighting up and beeping.

In one room of my new (40 year old) house the detector will beep when i place it near an outlet, switch, or light. Is this a huge problem or what could be the cause? It doesn't do this anywhere else in my house.

Also my daughter took a loose cable wire and looks like she was placing it on the outlet cover screw and left a burn mark on the outlet cover.

thanks for any help
 
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  #2  
Old 09-18-09, 06:48 AM
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Those pen things are nice toys with only limited uses. They measure the presence of an electromagnetic field not voltage. An experienced user can get some usable info but what you did probably means nothing. Why was there a loose cable? Why was your daughter swinging it around.
 
  #3  
Old 09-18-09, 07:54 AM
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The loose cable was the cable tv connection. we are redoing the flooring and have everything out of the room. My 6 year old was playing in the room and took the cable that was plugged in one end and loose on the other end and she put it on the outlet cover on the screw and it appears to have melted part of the cable. there is a large burn mark on the outlet cover centered around the screw. Leads me to believe the screw has electric going to it and the cable created a path to ground. Is this possible?

The phenomenon with the voltage detector does not occur in any other part of the house.
 
  #4  
Old 09-18-09, 09:00 AM
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Hi jgrant, if the funny readings and the issue with the burn mark are in the same room, yes they are probably related and very possibly you have a hot ground, either on the cable tv wire or on that outlet cover or circuit. I would suggest you shut off any breakers related to that room and carefully unplug the other end of the cable tv cable. Now, rather than me running you through the trouble shooting, there are some very good electricians on the board I'm sure will be along or Ray will be back and walk you through some steps. Be safe.

Also, have you or anyone done any wiring in the house recently or noticed any other issues like lights dimming or switches not working.

Bud
 
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Old 09-18-09, 09:30 AM
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Originally Posted by jgrant6108 View Post
I have a pen style voltage detector.
These are good as a safety check to make sure you aren't cutting anything live, but aren't reliable as a diagnostic tool. Sometimes you can even get it to buzz if you hold it up near the large veins in your neck and move it around.

Is this a huge problem or what could be the cause? It doesn't do this anywhere else in my house.
Any power within a couple inches would be normal for the tester to buzz.

Also my daughter took a loose cable wire...Leads me to believe the screw has electric going to it and the cable created a path to ground. Is this possible?
Yes it's possible, particularly if you have grounding problems on that circuit. You should have a grounded wiring method in a 40 year old house (1970ish), but I suppose it's possible that you don't. Do you know what type of wiring is on this circuit or in the rest of house for that matter? Is it a three prong or two prong receptacle?

If you feel comfortable doing so, switch off the breaker for that circuit, open up a receptacle box and let us know what wires are in there. If you don't want to do that, get or borrow a multimeter (should be $10-20), set it to AC volts 250V setting, and use the probes to measure voltage between each slot and between each slot and the metal plate or screw. Let us know what you find out.
 
  #6  
Old 09-18-09, 09:32 AM
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i bought a 3 prong tester from one of the box stores/it has a set of lites at the bottom & indicates problems ( reversed line/neutral-no ground-etc)
 
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Old 09-18-09, 09:50 AM
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Originally Posted by newtofta View Post
i bought a 3 prong tester from one of the box stores/it has a set of lites at the bottom & indicates problems ( reversed line/neutral-no ground-etc)
Unfortunately while they are good for a quick check you often need a different meter to diagnose a problem. They also can sometimes give a false reading. The reversed neutral indication for instance is often actually an open neutral. Best is an analog not digital multimeter. Or a neon test light. A solenoid voltage tester sometimes known as a Wiggy or Wiggins is good also.
 
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Old 09-18-09, 11:29 AM
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wow. thanks for the replies. I have a digital multimeter that I will use to test the circuits as suggested here. I won't be able to perform till later tonight and I will update with what I find.
 
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Old 09-18-09, 12:40 PM
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Be aware a digital multimeter can easily give false readings. I know every time you come up with a device I shoot it down but for a beginner some equipment is easier to interpret. See: Phantom voltage - Wikipedia, the free encyclopedia to understand why in my previous post I wrote "analog not digital" multimeter". However you can use it you just have to be aware some readings you get will be misleading. Suggest a cheap test light to double check any readings.
 
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Old 09-18-09, 01:03 PM
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These are very inexpensive ($5) and take all of the guess work out. You really don't need anything more sophisticated than this (international version pictured, US will have different numbers):

[broken image]

A digital (or analog) multimeter may also be helpful if further diagnosis is required, but this one will take care of 95% of home electrical.
 

Last edited by ibpooks; 09-21-09 at 11:08 AM.
  #11  
Old 09-18-09, 01:29 PM
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The only thing I use the beeper taster for is to see if there is anything in a box that is hot. It may not tell me which wire, but it will at least tell me theres something.

Try this for fun: Find some REALLY high power lines and try out your beeper while under them.
 
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Old 09-18-09, 04:26 PM
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Anxiously waiting for tonight's results.

If you turn down the adjustment dial on your wire tracer, you can better isolate wires when they are grouped close together, in case you did not know.
 
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Old 09-18-09, 05:12 PM
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looks like my ground wire is hot. what causes that?
 
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Old 09-18-09, 05:31 PM
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Originally Posted by jgrant6108 View Post
looks like my ground wire is hot. what causes that?
Induction from other wires. A good example of phantom voltage. Only way to know for sure is to check it with a meter or the tester above.
 
  #15  
Old 09-18-09, 05:42 PM
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Here is what I did.

I took my digital multimeter and poked into the holes. I got a 120v reading when I connected black to white and white and ground. I got nothing when I connected black to ground. That led me to believe that my hot and neutral got switched somewhere(i was told that by a respectable guy at my work).

I then took the outlet out of the wall and actually touched the connections with the bare ground wire. I got the same results.

I then took the coaxial cable wire and connected it with the outlet using my multimeter and I got a hot reading when I connected to the ground and to the black side. no reading when connected to the white.

Thinking something was amiss I took the coaxial cable(it is quite long) to another room on a different circuit and tested again using my multimeter. I got a reading of 120v when I connected this time to the black only. White and ground gave me no reading.

This leads me to conclude that my ground on that circuit is hot. Will a 3prong tester confirm this.
 
  #16  
Old 09-18-09, 05:45 PM
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This might also explaing why I get a hot reading on my volt tester. If the ground is hot then the little screws in the covers are also hot correct?

Along with this wouldn't my entire metal parts in the ceiling fan also be hot if it is connected to this hot ground?

I can't test that till my wife gets home. I am somewhat reluctant to ask my 9,6,and 2 year old to be my helpers
 
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Old 09-18-09, 06:11 PM
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By testing with an extension cord, by touching say the small male spade on your extension cord (you'll need someone to hold that spade on that ground, carefully, unless you have alligator clip jumper wire) to the ground wire, with the extension cord run to a totally different circuit in the house, and then plug your voltmeter probe into the small slot of the extension cord, and other voltmeter probe to other circuit's ground, what do you get? If you get 120, then yes, that ground is hot, for sure! Also try the same test, only instead of running the extension cord to another circuit, run it to a metal plumbing pipe to make sure all your ground is not somehow hot.

Yes, the metal screw hole is connected to the ground of the outlet. That is what makes 3 x 2 outlet adapters work(if the outlet or box is grounded by wire BX cable or EMT between panel box and outlet), if you hook the 3 x 2 tab to the outlet screw.
 
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Old 09-18-09, 06:27 PM
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with the extension cord run to a totally different circuit in the house, and then plug your voltmeter probe into the small slot of the extension cord, and other voltmeter probe to other circuit's ground, what do you get? If you get 120, then yes, that ground is hot, for sure!
ecman51` If it is plugged into a correctly wired outlet the narrow slot should be 120 to ground. The wide slot should be 0 to ground. Was that a typo or did I misunderstand? Narrow slot to black should be 0v or 240v.

I would suggest with small kids in the house the breaker should be left off except for testing till the problem is resolved. I almost wonder if you have both a reversed neutral and a bootleg ground. That is a ground made by jumpering the neutral to ground.
 
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Old 09-19-09, 01:59 PM
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The cord is only a jumper. I simply chose to tell him to use the small prong at the one end of the cord, and the small slot other end of the cord, to make it work as a jumper. He can also use the big slot and big prong. He can also use the round ground hole at one end and the ground prong on the other.

I hope we get to see if this issue gets resolved.
 
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Old 09-19-09, 03:04 PM
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Originally Posted by ecman51` View Post
The cord is only a jumper. I simply chose to tell him to use the small prong at the one end of the cord, and the small slot other end of the cord, to make it work as a jumper. He can also use the big slot and big prong. He can also use the round ground hole at one end and the ground prong on the other.

I hope we get to see if this issue gets resolved.
Done that my self just wasn't sure it would be clear to the poster because of the line:
with the extension cord run to a totally different circuit in the house,
.
 
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Old 09-19-09, 03:19 PM
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I meant for him to run the cord so that the cord is not plugged into any circuit, but is draped across the floor, laying there in front of say the outlet in question and some other outlet elsewhere in the house, on a confirmed other circuit, but not plugged into any of those outlets. Just laying there ready for him to use as a jumper. And for him to also use this jumper between the questionable oultet and say a metal water supply line so he can find out once and for all if that supposed hot ground wire was really hot or not, without being fooled in any other way.

Any explanation as to if or how that ground wire was hot while the other GFCI was tripped? That is why I'd like to know if that ground wire was really hot or not. Sort of in limbo on the answer to this, on this thread, so far, anyway. For all we might not know, he still may have something messed up in his house, even though he thinks everything is working fine now. ???
 
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Old 09-19-09, 03:27 PM
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I mentioned a bootleg neutral on a reversed hot neutral circuit. No ground to the bootleg and all downstream would be hot ground.
 
  #23  
Old 09-21-09, 10:22 AM
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I also took my voltmeter and the cable tv coaxial cable and placed one end of voltmeter to the cable and another to a screw that holds the glass globe onto the ceiling fan. I got 120V as a reading.

You would like me to now lay an extension cord on the floor to another outlet on another circuit(I understand this concept) but not plug it in to either outlet. and then use my meter to determine if I have a hot ground?

Can't I just run the 3 prong extension cord to a confirmed good outlet on another circuit, pug it in, and touch my meter probes to both grounds and If I get a 120v reading then that means my bad ground is hot?
 
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Old 09-21-09, 11:08 AM
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Originally Posted by jgrant6108 View Post
Can't I just run the 3 prong extension cord to a confirmed good outlet on another circuit, pug it in, and touch my meter probes to both grounds and If I get a 120v reading then that means my bad ground is hot?
Yes you could, but finding a "known good outlet" in a house with the problems that yours seems to have can be a challenge.
 
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Old 09-21-09, 12:09 PM
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If you have steel or copper pipes you can connect the extension cord to that. I would simply wrap a bare wire around all the screws of a spare receptacle, fasten that wire to the plumbing and then plug the extension cord into that. Or go to the ground rod for the meter.
 
  #26  
Old 09-21-09, 01:36 PM
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i have alot of dog wire fencing left over. is that acceptable for rays idea? will any copper plumbing suffice? i have baseboard water heat available in the next room if that will work?
 
  #27  
Old 09-21-09, 01:41 PM
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I have used that 3 prong tester from hardware store on every outlet in my house. They all come up wired good except for this circuit. Am I to believe that this peice of equipment won't tell me accurately that my other outlets are good.

the outlet tester is saying that I have a nuetral/rev problem in this room. But the paperwork for the tester says that it won't detect two hot wires.
 
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Old 09-21-09, 04:35 PM
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Originally Posted by jgrant6108 View Post
i have alot of dog wire fencing left over. is that acceptable for rays idea?
The extension cord is better. Bare wire could pose a danger.
will any copper plumbing suffice?
Yes if the whole house is plumbed in copper to the meter.
 
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Old 09-23-09, 09:26 AM
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I took the dog fencing(it has insulation) wrapped it around the copper plumbing and used my multimeter on the ground of outlet. It tested at 120v. In my mind I have a hot ground. The next step is finding the cause. What is the most likely cause?
 
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Old 09-23-09, 10:30 AM
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Check from the black wire to ground and the white wire to ground if you have 120v to white and 0v to black you know at the very least you have a reversed hot to neutral. Some where either unintentionally you have a bare ground touching a neutral or someone has intentionally tied neutral to ground.

I suspect the latter. If the ground went all the way back to the breaker box the breaker should trip, Somewhere the ground is broken. First step is to test every receptacle on the circuit. It could though be in a switch box, a light or a Jbox you are unaware of. I suspect a circuit ran with ungrounded Romex from the box. Someone later added on with grounded Romex and that is where the problem is but it is only a guess. Keep the circuit Off except for testing till you find the problem. This is dangerous with small children around.
 
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Old 12-08-10, 09:24 AM
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sorry for the over year update. Well after much searching nothing seemed to work. I forgot to look under one fixture though. Today I have the day off so I took the fixture out and underneath the light there is a junction box with 5 wires comming into it.(the wires are common household wires, there are 3 wires, black, white, ground wire in each). one of the white wires are tied with 4 black wires, 4 white wires are tied together and the last black wire goes to the light. Does this sound right?
 

Last edited by jgrant6108; 12-08-10 at 09:25 AM. Reason: spelling
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