Use of non-contact voltage detector for verifying no voltage present

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Just a quick question,

Does a "non-contact" voltage detector qualify as the final test for "no-voltage" prior to working on, hopefully, de-energized parts in equipment which has been locked/tagged?

thanks!
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
We use non-contact detectors, all the time for systems >2400V. But we still use a live-dead-live test procedure.

Maybe you could provide a few more details
 

al

Senior Member
Location
Minnesota
70E requires testing phase to phase and phase to ground. For >600V you need to use phasing sticks to do this. It is my understanding that not many comapaines do this, they just use the non contact for >600V.
 

jim dungar

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Location
Wisconsin
Occupation
PE (Retired) - Power Systems
70E requires testing phase to phase and phase to ground.
Voltage testing is required - methodology is not.

We are definitely compliant with NFPA70E and OSHA, we do not use phasing sticks >600.
 

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
Most of the commonly used low voltage non-contact testers have too many possible false negatives to be used to verify lack of voltage.
 

al

Senior Member
Location
Minnesota
Voltage testing is required - methodology is not.

We are definitely compliant with NFPA70E and OSHA, we do not use phasing sticks >600.

From 70E: "Test each phase conductor or circuit part both phase-to-phase and phase-to-ground."


I dont see how a non contact tester can do this for any voltage.
 

iwire

Moderator
Staff member
Location
Massachusetts
I use them all the time for this. Like any tool you need to know their limitations.

I also use the 'sleeve test' ;) You rub the tester on your arm to confirm it is working, check the circuit and then test the tester again. If a non-contact tester is good enough for pretty much every lineman in the country they are good enough for me.

That said when I do LOTO I check with my meter. I use the non contact tester when at the other end of the circuit and want to ensure the cable or whatever is actually off. When you are dealing with the blunt cut off end of cable the non-contact tester is much safer then trying to use meter probes.


One question I do have for you guys that say no, they are not for this use.


What use are they for?
 

al

Senior Member
Location
Minnesota
I agree that a non-contact tester is safer. What we do for MV is:

Non contact test, then contact test (phasing sticks) phase to phase and phase to ground, then static discharge, then ground cluster.

Al
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
I agree that a non-contact tester is safer. What we do for MV is:

Non contact test, then contact test (phasing sticks) phase to phase and phase to ground, then static discharge, then ground cluster.

Al

For those who said yes, I say it depends on who is using it. I wouldn't train an apprentice by allowing HIM to use a pen tester exclusively. With experience comes wisdom (or it should). If I test a circuit live and then turn off the reasonably assumed breaker and then test it dead and recheck my tester and I am not intending direct contact with the wires, I will use my pen tester. If I have a bare exposed wire sitting there I expect to grab hold of, it doesn't take very long to double check it with my wiggy that I always carry. Experience. Wisdom! Just saying.
 

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
Including the obvious one that they will not indicate DC, as in a PhotoVoltaic installation....
I am thinking about things like the fact that at least one maufacturer says they may not work if you are using it while standing on a fiberglass ladder.
 

PetrosA

Senior Member
I am thinking about things like the fact that at least one maufacturer says they may not work if you are using it while standing on a fiberglass ladder.

Huh?!? Do they also recommend taking off your rubber soled shoes before testing? Sounds like that company needs some new engineering blood.

The only situation I've found with my Fluke pencil tester that will give a false NEGATIVE on a hot wire is if I'm holding on to the same hot wire I'm trying to test. If this happens, the tester still works, but it will light up for the neutral and ground instead of the hot wire.
 

Aleman

Senior Member
Location
Southern Ca, USA
I use mine all the time and generally trust it. But if I am going to be doing wiring, terminals, part changes etc I verify with my meter also, especially on
circuits above 120V.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
This is from Fluke.
When using the Tester, if tip does not glow, voltage could still be present. The Tester indicates active voltage in the presence of electrostatic fields of sufficient strength generated from the source (MAINS) voltage. If the field strength is low, the Tester may not provide indication of live voltages. Lack of an indication occurs if the Tester is unable to sense the presence of voltage which may be influenced by several factors including, but not limited to:
●Shielded wire/cables
●Thickness and type of insulation
●Distance from the voltage source
●Fully-isolated users that prevent an effective ground
●Receptacles in recessed sockets/ differences in socket design
●Condition of the Tester and Batteries
This is from Klein.
WARNINGS:
It is important that users of this tester read, understand, and follow all warnings, cautions, safety information, and instructions in this manual before operating or servicing this tester. Failure to follow instructions could result in death or serious injury.
Risk of electric shock and burn. Contact with live circuits could result in death or serious injury.
Use caution with voltages above 30V AC as a shock hazard may exist.
? A steady red glow and continuous beep indicates voltage present.
? If no indication, voltage could still be present.
?In bright light conditions, the LED visual indicators will be less visible.
? Do not use if green LED is not illuminated.
This is from Ideal.
IMPORTANT SAFETY INFORMATION
Read and understand all of the instructions and safety information in these operating instructions before
using this tester.
WARNINGS
To avoid possible electric shock, personal injury or death follow these guidelines:
? Do not use if green light is not illuminating on tester.
? Do not use if tester appears damaged or is not operating properly.
? Do not use tester for more than the rated voltage on the tester.
? Do not use without the tester fully assembled.
? This tester will not detect the presence of DC voltage.
? This tester will not detect voltages at a distance, such as through walls, metal conduit, or shielded wire.
? Voltage detection maybe affected by outlet design, insulation thickness/type.
? Do not assume that no voltage indication means the circuit is de-energized.
? Voltages below 40VAC will not be detected by the 61-025 but are still shock hazards that can result in injury or death.
? Use the 3 Point Safety Method. (1) Verify tester operation by measuring a known voltage. (2) Apply tester to circuit under test. (3) Return to
the known live voltage again to ensure proper operation.
? Ensure all fingers are behind finger guard when testing for voltage.
? If this tester is used in a manner not specified by IDEAL, protection provided by the product may be impaired.
? Comply with local and national safety requirements, including the use of appropriate personal protective equipment.
It appears to me that Klein and Ideal do not intend for their non-contact testers to be used to prove that the circuit is safe to work on.
 

templdl

Senior Member
Location
Wisconsin
This is what my personal practices are:
It is important to know what the voltage range of the device is.
It is imperative that the testing device be checked by testing on a known energized voltage source first, then checking the circuit in question, and then verifying that your testing device is working against a known energized voltage source. I have a fluke non contact tester and I. Never trust it to be working unless I test it by checking a know energized voltage source.
This is described in the instructions for the device.
It is very important not to disregard logical sense and turn your brain off putting it into automatic mode.
 

jdsmith

Senior Member
Location
Ohio
Also look at the minimum voltage that the testers will detect. NFPA 70E-2012 (110.8(B) & elsewhere) considers anything above 50V to be hazardous. Many of the Fluke models are rated to detect 90-1000V, or they offer a 20-90V model. How many folks use both the 90-1000V model only and may be missing voltages in the 50-90V range?
 
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