×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Can Non Contact Voltage Detectors be trusted?

Can Non Contact Voltage Detectors be trusted?

Can Non Contact Voltage Detectors be trusted?

(OP)
We have been using Non Contact Voltage Detector
I like it because one hand operation and dont have to take eyes off what I am holding it to and see the red light, if it lights. Also I like it because dont have to worry if the ground is good for it to function. Also, I can give a quick check of the bulb by touching my shirt to see if it turns red.
Everything seems so perfect. IS it?
All I want to know is are these Non Contact Voltage Detectors reliable?
Some times I wonder
Been using a voltmeter long enough that I trust it
I think the Non Contact Probe works by capacitance.
Thank you for anybodys input.

RE: Can Non Contact Voltage Detectors be trusted?

I would not trust it on DC. Or rather - I would not trust it at all if there are any DC installations in the building. Always check voltage with a reliable instrument before working on a circuit. Short and ground is also a good practice. Will keep you from being burnt if someone swithes power back on - which happens more often than we like to think.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Can Non Contact Voltage Detectors be trusted?

They don't work on dc.  I wouldn't trust my life to one even on an ac circuit.  

Standard procedure should be to test first with non-contact probe - if it lights up, you know it's hot.  If it doesn't, it MIGHT be dead.  At that point, you can test with contact voltage probe specifically designed for voltage testing.  DMMs are not recommended for voltage testing.  A dedicated voltage tester is less likely to fail, or to be used on the wrong setting, or with leads in the wrong holes.  

(I know - do as I say, not as I do....) looking around

RE: Can Non Contact Voltage Detectors be trusted?

Prove your tester before you use it, then prove it still works after you have tested. Otherwise... are you really sure it is dead?
 

----------------------------------
  Sometimes I only open my mouth to swap feet...

RE: Can Non Contact Voltage Detectors be trusted?

There are cases when using this type of tester to test for power on cables or cords with paper fillers, where if the paper is wet, the tester will no power when in fact the power is on.
Don

RE: Can Non Contact Voltage Detectors be trusted?

That's interesting - hadn't heard that before. Something to be aware of if working in old buildings.
 

----------------------------------
  Sometimes I only open my mouth to swap feet...

RE: Can Non Contact Voltage Detectors be trusted?

frankee, we've using such device on our 13.8KV switchgears only after the system were shutdown, as well as when our metering instrument depicts abscence of power, and a physical draw out of Power CBs were carried out. These actions were just few of our routines.
 I hight restrict not to use such device when the system is live. We have cases of flash over, and mishandle.

RE: Can Non Contact Voltage Detectors be trusted?

Sorry non contact voltage detectors on 13.8kV.......

HV is specialised and only the right gear should be used on this sort of system - Home Depot 9.99 non contact testers are not the type of testers you want to be using on 13.8. Believe me ! Next you will be looking for a 13.8kV lamp to make up a set of test lamps.

Rugged

RE: Can Non Contact Voltage Detectors be trusted?

I trust it to the degree of comforting myself on small/ low energy jobs where I don't physichally come in contact with conductors. As example, when needing to do retightening on a lot of (100's) small screwterminals I always "brush over" with such a device to quickly discover if there was something the main breaker did not kill, or if I'm in the wrong box (which have happened).
I most definately do not rely on this if I need to "handle" the wiring, or work on high energy circuits.

RE: Can Non Contact Voltage Detectors be trusted?

Non contact detectors are accidents waiting to happen. I believe in a domestic enviroment they may have some value to the DIY industry

RE: Can Non Contact Voltage Detectors be trusted?

resqcapt19 said;

"when using this type of tester to test for power on cables or cords with paper fillers, where if the paper is wet, the tester will no power when in fact the power is on."

That's worth hearing Don,  that explains, or confirms some of my own experiences!

I use one made by Fluke all the time.  I've used others, and some have some other/nicer features than the Fluke,,, BUT as mentioned above and in every electrical safety class and text, as well as service, troubleshooting, instrumentation, etc.: ONLY use a tester you trust because it has been tested and proven.  They are only intended for a cursory check, and are simply a fairly good indicator.

RE: Can Non Contact Voltage Detectors be trusted?

Hi, i agree with Hewlett, i never ever rely on them for disconnections. I think their main purpose is to let you know that that's power there, so you don't have to get into a terminal box, cabinet etc.. saves time. I only use them in fault finding if I want to know a supply is switching when it should etc.. and if it showed up an error, then out comes the voltage tester. Also I have had experience with them not working through screened cable.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources