......detected voltage when no voltage is present??.......I will give you the situation...the lighting Tech was installing a the lamp/ballast assembly for a street fixture. prior to him starting the job I suggested to him that I should remove the fuses at the pole base...Now this street fixture is a 240 volt single phase with a ground wire....so we have 3 wires going up this pole 2 hots and a ground wire...Now with both fuses removed.The lighting tech checked both wires with a Greenlee GT-11 voltage detector (Tick tracer CAT 4 rating 50-1000volts) and on one leg ( not the ground wire )the detector was indicating that leg was hot but it wasn't can you tell me why the detector was detecting when it shouldn't have???? the lighting tech asked me but I didn't have an answer all I could tell him was that there must have been a magnetic field on the wire for the detector to go off..... can you help?????
Why do voltage detectors ......
- Thread starter msilva
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hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Why do voltage detectors ......
Many times these will pick up stray fields from the wires where ran with other conductors in the same conduit but the field can transverse back and forth along the wire and since the grounding conductor is ran with the ungrounded conductors it is problem coming from the grounding conductor. these testers are not a good trouble shooting tool because of this all the do is indicate if a voltage might be present and if they do detect a voltage then you are supposed to use a loaded voltage meter to confirm it. Do not rely on these as they can send you in all sorts of directions looking for false voltages like a DVM can.
Many times these will pick up stray fields from the wires where ran with other conductors in the same conduit but the field can transverse back and forth along the wire and since the grounding conductor is ran with the ungrounded conductors it is problem coming from the grounding conductor. these testers are not a good trouble shooting tool because of this all the do is indicate if a voltage might be present and if they do detect a voltage then you are supposed to use a loaded voltage meter to confirm it. Do not rely on these as they can send you in all sorts of directions looking for false voltages like a DVM can.
physis
Senior Member
Re: Why do voltage detectors ......
I have two and they baoth act a little different. I can kind of tell when they're lying to me. They're sort of like kids, they kind a mummble when they're not telling the truth.
I think they're invaluable but you have to know that it's just sort of a guess and you can't rely on it.
As far as what it's detecting. I'm only guessing but I'd have to say EMF. It doesn't need a current so it wouldn't be a magnetic field.
I have two and they baoth act a little different. I can kind of tell when they're lying to me. They're sort of like kids, they kind a mummble when they're not telling the truth.
I think they're invaluable but you have to know that it's just sort of a guess and you can't rely on it.
As far as what it's detecting. I'm only guessing but I'd have to say EMF. It doesn't need a current so it wouldn't be a magnetic field.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Why do voltage detectors ......
Well then a static field?
Well then a static field?
zog
Senior Member
- Location
- Charlotte, NC
Re: Why do voltage detectors ......
All proximity type detectors (I.E. Tic Tracer) detects electric fields, not magnetic fields. You are probally picking up a field from another energized part.
Using a direct contact detector (Like a Fluke) will tell you the "Truth".
All proximity type detectors (I.E. Tic Tracer) detects electric fields, not magnetic fields. You are probally picking up a field from another energized part.
Using a direct contact detector (Like a Fluke) will tell you the "Truth".
Re: Why do voltage detectors ......
I don't know why all of you are arguing what a non-contact volt meter detects, when the truth of the matter is, you should use a conventional volt meter when preparting to work on a de-energized circuit. You pulled the fuses, why did you not check the load side of the fuses with a conventional volt meter?
As for the theory of electromotive forces existing without magnetic fields, what makes any of you qualified to answer these questions?
I am pretty sure, when I took Physics II, electric fields and magnetic fields co-exist. Thus we have generators and electro-magnets. I am not qualified to answer this so I encourage all of you to consult someone who is.
I don't know why all of you are arguing what a non-contact volt meter detects, when the truth of the matter is, you should use a conventional volt meter when preparting to work on a de-energized circuit. You pulled the fuses, why did you not check the load side of the fuses with a conventional volt meter?
As for the theory of electromotive forces existing without magnetic fields, what makes any of you qualified to answer these questions?
I am pretty sure, when I took Physics II, electric fields and magnetic fields co-exist. Thus we have generators and electro-magnets. I am not qualified to answer this so I encourage all of you to consult someone who is.
Re: Why do voltage detectors ......
Mega, I believe the proximity testers work with capacitive coupling between the hot conductor and the tester. That being the case, they would only work on AC voltages.
An electric field is created by a difference of potential, i.e., a voltage difference. A magnetic field is created by motion of electric charges, i.e., a current. Often we see both phenomena at the same time.
Sam, EMF means Electro-Motive Force.
Mega, I believe the proximity testers work with capacitive coupling between the hot conductor and the tester. That being the case, they would only work on AC voltages.
An electric field is created by a difference of potential, i.e., a voltage difference. A magnetic field is created by motion of electric charges, i.e., a current. Often we see both phenomena at the same time.
Sam, EMF means Electro-Motive Force.
zog
Senior Member
- Location
- Charlotte, NC
Re: Why do voltage detectors ......
Rattus hit it right on the head
"what makes any of you qualified to answer these questions?"
"I am not qualified to answer this so I encourage all of you to consult someone who is."
Mega VAR - Sounds like you are unqualified to question who is qualified to answer what.
Rattus hit it right on the head
"what makes any of you qualified to answer these questions?"
"I am not qualified to answer this so I encourage all of you to consult someone who is."
Mega VAR - Sounds like you are unqualified to question who is qualified to answer what.
Re: Why do voltage detectors ......
"what makes any of you qualified to answer these questions?"
Maybe because our title is electrician and whos to say whos qualified or not?
IN MY OPINION NOT YOU.
[ July 27, 2005, 07:13 PM: Message edited by: ronaldrc ]
"what makes any of you qualified to answer these questions?"
Maybe because our title is electrician and whos to say whos qualified or not?
IN MY OPINION NOT YOU.
[ July 27, 2005, 07:13 PM: Message edited by: ronaldrc ]
physis
Senior Member
Re: Why do voltage detectors ......
Well it could be Rattus. My electron microscope
hasn't been working right lately and I'm relying on somebody else for these images until it's either fixed or I get another one.
Edit: The last time I looked at it the atoms didn't seem to be the right size for copper.
[ July 27, 2005, 10:48 PM: Message edited by: physis ]
Well it could be Rattus. My electron microscope
hasn't been working right lately and I'm relying on somebody else for these images until it's either fixed or I get another one.
Edit: The last time I looked at it the atoms didn't seem to be the right size for copper.
[ July 27, 2005, 10:48 PM: Message edited by: physis ]
Re: Why do voltage detectors ......
Wow, looks like all of you got mad.
Well since all of you are qualified, I guess you have heard of Ampere-Maxwell's law, which states a time-varying electric field produces a magnetic field just as a time-varying magnetic field produces and electric field (Faraday's Law).
Electromagnetic waves (present around AC circuits) consist of oscillating electric and magnetic fields, which are at right angles to each other and also at right angles to the direction of wave propagation.
Relating to an AC circuit, which changes potential in relation to a time variable, thus the sinusoidal waveform, the electric field produced by the conductor is changing and the above applies.
Thanks for catching the typo of electrician Celtic. I guess you had to dig for something.
I agree with all of you, I am not qualified to answer all of these questions. I am releive to know, however, that there are such fine people to make assumptions in life to help make the world a safer place, or kill someone.
Wow, looks like all of you got mad.
Well since all of you are qualified, I guess you have heard of Ampere-Maxwell's law, which states a time-varying electric field produces a magnetic field just as a time-varying magnetic field produces and electric field (Faraday's Law).
Electromagnetic waves (present around AC circuits) consist of oscillating electric and magnetic fields, which are at right angles to each other and also at right angles to the direction of wave propagation.
Relating to an AC circuit, which changes potential in relation to a time variable, thus the sinusoidal waveform, the electric field produced by the conductor is changing and the above applies.
Thanks for catching the typo of electrician Celtic. I guess you had to dig for something.
I agree with all of you, I am not qualified to answer all of these questions. I am releive to know, however, that there are such fine people to make assumptions in life to help make the world a safer place, or kill someone.
Re: Why do voltage detectors ......
And your welcome...I didn't have to dig at all ~ it was painfully obvious....but dutifully, you did as you were told...thanks for being a good boy.
umm..before you pat yourself on the back too much...I wasn't mad - not even mildly annoyed
And your welcome...I didn't have to dig at all ~ it was painfully obvious....but dutifully, you did as you were told...thanks for being a good boy.
physis
Senior Member
Re: Why do voltage detectors ......
Do you believe that there is a magnetic charge?
Edit:
[ July 28, 2005, 03:06 AM: Message edited by: physis ]
The adaptation of Ampere?s law by Maxwell to explain a charging capacitor. ?Displacement current?. Do you need the equations?
Do you believe that there is a magnetic charge?
What's your point? Where?s the imminent danger you believe we?re putting people in from discussing how a tick tracer works?
Edit:
Do you know the right hand rule too?
[ July 28, 2005, 03:06 AM: Message edited by: physis ]
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