Is a voltmeter an electric field meter? Silly question, but could have industry wide ramifications

[kwired]

This really sounds like something for the lawyers to untangle, not the engineers.

The lawyers are not electrical experts though, they need to work with some sort of expert to learn how things work relative to the problem here.

An opposing lawyer would likely have his experts as well. Hopefully experts for both sides have similar things to say about it or we could end up with a judgement that is incorrect depending on who comes out ahead in their case. The legal system isn't perfect, whoever presents the most convincing case to a judge or jury wins.

 

[dkarst]

Back to the question from the OP, I would agree that a standard DVM is not an electric field meter when used in a customary manner using the probes to touch conductors and measure the voltage potential. However, many multimeters these days incorporate a "proximity" or non-contact testing capability as well. Fluke calls it "Volt alert" but many offerings have it and it works the same as the little test pens many folks carry to check if wire is live.

As to whether an electrician is out of their area of expertise using a multimeter with non-contact capability to check a streetlight is a question I can't answer. I guess if it was me and job on the line, I'd see if there is a better piece of test equipment than the multimeter but I haven't really looked.

 

[kwired]

By electric field meter do they mean something that measures the strength of a field, like in gauss, or a non-contact device that simply senses the presence of a field?

By the truest definition, any device that does not connect directly into the wiring works off of an "electric field'. Watch out for lawyer speak versus industry slang.

Isn't Gauss measuring a magnetic field? And wouldn't you need to have current to have the magnetic field? So if that is true you could have an energized line but with no load on it and no reading on Gauss measuring devices?

Non contact voltage detectors are detecting capacitive coupling for the most part AFAIK.

 

[KidFishJack]

As far as encroachment that is for the lawyers. But there is a safety concern potentially with one vs the other method of looking for a fault condition. Not sure the reason a fault is being looked for, there are many different sorts of faults that could be dangerous or even deadly. While a typical volt or multimeter will give a very accurate voltage reading vs the electrical field meter, the EFM will provide a safer test as it will allow to test for presence of electrical charge without direct contact with a potentially high voltage fixture. Now if the test is looking for a potential primary fault onto a street light it is even bigger safety issue to try to use a simple multimeter, with the potential to "blow up" the meter and severely injure the person doing the testing.

Hi Fred

Your profile location mentions you are from upstate NY. The reason for this testing goes back 20 years when a woman, Jodie Lane, was electrocuted while walking her dogs in NY City. In 2005, the NY State Public Service Commission passed laws requiring certain electric utilities in the State to perform this type of safety testing. (Case 04-M-0159: "Proceeding on Motion of the Commission to Examine the Safety of Consolidated Edison Company of New York, Inc.'s Electric Transmission and Distribution Systems.") Other States and municipalities have slowly adopted similar testing rules. You are right...if a utility primary phase fault voltage was on a streetlight, that would of course damage the best multimeter unless a high-voltage probe was in use. Thankfully, at least here in the USA, there has never been a reported case of a utility phase voltage being found on a streetlight- all 600-volt stuff or less being found and tested for.

KFJ

 

[Flicker Index]

Was not sure if this question should be posted under General Forum, Safety Forum, or Troubleshooting Forum...or is permitted at all.

First, we do not believe that a voltmeter, or the voltage function of a multimeter, is an electric field meter.

This question comes up as a company who uses electric field meters to find faults on streetlights, is asserting that using a volt/multimeter to troubleshoot lighting circuits encroaches on their service offerings. This isn't hypothetical- we are in the middle of this disagreement right now.

We understand reading the terms of this Forum, these questions cannot be used or construed as expert advice. However, we are hoping someone here could point us in the direction of any articles, technical papers, or demonstration devices/apparatus that can show the difference to a layperson.

Our concern isn't just for our livelihood, but for any electrician or electrical firm who works on street, parking lot and roadway lighting systems.

Thank you,

KFJ

In what context?

What is A Non-Contact Voltage Tester? | Fluke

What is a voltage tester, detector, pen, sniffer or sensor? How do they work and how to you use one? How are they different than a multimeter? Discover here.

www.fluke.com

"A built-in sensor at the tip of the tester detects the presence of voltage when touching a conductor, outlet, or supply cord. By holding the tool, you are the ground reference through capacitive coupling. When the tip glows red and the unit beeps, you know voltage is present."

Connect two L.E.D.s back-to-back, attach a 0.01uF capacitor in series, then attach a needle on the end, and potato on the other.
(needle)--||--(L.E.D.s)---(potato). Stick the needle into a 120v receptacle while holding the potato and the LED will light up due to the capacitive coupling through the 0.01uF cap. The films within the capacitor are not in metal-to-metal contact with each other.

Instead of 120v outlet, get the other end close enough to a high enough voltage of a conductor and the LED will glow without touching, again because of capacitive coupling. The probe tip is not touching the electric source, but it's still capacitively coupled.

So, from physics point of view, it's the same capacitive coupling.

 

[hbiss]

Ok. "This question comes up as a company who uses electric field meters to find faults on streetlights..." If you could provide information as to what the equipment is that they are using or at least a picture of it we could help you better. I think your question has been answered several times over but specifics would help.

-Hal

 

[suemarkp]

You could google "trifield meter". These are meters that detect magnetic fields, rf fields, and electric fields. They are used by by people who are trying to detect "bad emf", UFOs, and ghosts. I would say the trifield meter, or a similar EMF meter looking for electric fields, non contact voltage testers, and volt meters are all different mechanisms to determine if electricity is present with the main factor being detection range and voltage thresholds.

The voltmeter is the most sensitive since it works by conduction. But if the object is insulated or distant, you need a non contact or E field meter. But non contact shows nothing if the voltage is too low. Not sure if E field meter would detect DC. Most seem to have an AC frequency range, and at some point it becomes an RF meter.

 

[roger]

The investigation said Jodie contacted 57 volts and one of her dogs suffered burns from momentary contact, seems to me there is a good bit of untruth being passed around regardless of fault testing equipment.

 

[hbiss]

You could google "trifield meter". These are meters that detect magnetic fields, rf fields, and electric fields. They are used by by people who are trying to detect "bad emf", UFOs, and ghosts.

I prefer something that wouldn't be used by Ghost Busters or the Tin Foil Hat crowd.

This is a professional grade instrument such as what I talked about earlier and probably what they used

https://www.aemc.com/products/high-voltage/highvoltage-275HVD

In 2005, the NY State Public Service Commission passed laws requiring certain electric utilities in the State to perform this type of safety testing. (Case 04-M-0159: "Proceeding on Motion of the Commission to Examine the Safety of Consolidated Edison Company of New York, Inc.'s Electric Transmission and Distribution Systems.") Other States and municipalities have slowly adopted similar testing rules.

So that spawned companies that sold municipalities a bill of goods and allowed the utilities to say "see, we're complying by contracting with these guys".

-Hal
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