Talk:Stray voltage

Effects on farm animals

I object to the remark that my article was patent nonsense. It may not be an in depth scientific discussion of the problems with the electric transmission system in the United States but it is certainly a verifiable and truthful overview. Stray Voltage is a very serious issue in any area of our country that has a number of dairy farms. I am in Wisconsin, the "dairy state" and I know that dairy farmers are battling this issue continually in addition to the issue of the power of the utility companies to prevent the dairy farmers from finding satisfaction.

In the US, electricity is sent out on transmission lines. All electricity sent out, must return to the substation it came from. Electricity will follow the path of least resistance, and our utility companies commonly use the earth to provide that path. Anything in the way of that path may be affected by the electricity as it returns. Dairy farms are often wet (water, manure) and the cows are in direct contact with the earth. They also frequently have a lot of metal work, another electrical conductor. So, if a dairy farm is between the substation and a transformer, they may be inundated with the current as it returns to the substation.

All lactating and or/gestating mammals are affected by stress. Stress causes hormonal changes that may prevent the animal from producing milk or even having a normal or natural labor and delivery. Stray voltage has been documented as causing stress. Some of the ways it may cause stress are to cause electric shocks, stress, distress, or discomfort when in contact with watering devices.

Dairy (milk) is a huge industry in the USA. Stray Voltage causes thousands if not millions of dollars of lost revenue to dairy farmers. However, Utility companies are also very powerful financially and they would have to acknowledge culpability, and then change the way they transmit electricity to solve this issue.

Waiting4rain 01:44, 31 May 2007 (UTC)

• OK. I'll withdraw the speedy. But this article needs serious re-writing. It reads like a rant from a mad scientist rather than an enclopaedic article. It's uncategorised, lacks structure and doesn't follow wiki conventions. Dontdoit 02:07, 31 May 2007 (UTC)

• • Well, I renominated it. Besides the speedy reasons, it reeks of POV pushing and OR. If this is to be kept, it needs some really good support. By the way, there is a term called stray voltage and this article does not do the correct usage justice. That usage may only be a dictdef so not deserving of an article here. Vegaswikian 02:19, 31 May 2007 (UTC)

Also, although I'm not an expert on the US, I doubt that it's correct that they use earth return for <emph>transmission</emph> although they may use it for distribution. It's also not correct to say that earth return is not used in Europe; it is used; albeit only rarely in very remote areas. Dontdoit 02:17, 31 May 2007 (UTC)

The original article was impermissibly POV.

But "stray voltage," especially on dairy farms, is a very notable concept and a good article can be written on it from reliable sources. One would be US Department of Agriculture Handbook No. 67, "Effects of Electrical Voltage/Current on Farm Animals. There is also "Ground Currents and the Myth of Stray Voltage" by O.C. Seevers, P.E.

There was an article on this in Electrical World magazine in the early 1990's which it will cost a trip to a university library to find. The article said it was a myth that stray voltage, ground current and EMF were the same thing. It was a myth that electrical systems should not be connected to the earth (to avoid having earth currents flow) It was a myth that stray voltage is caused only by the utility, so the utility should fix it. It said that improperly wired farm equipment often caused higher levels of stray voltage than could be caused by the operation of the utility system.

On the utility side, unbalanced loads and inadequately sized neutral, along with poor grounding at the poles and transformers, can contribute to stray voltage. Having single phase and two phase branches on the distribution system can contribute to stray voltage. Trees in need of trimming can make repeated intermittent contact with high voltage conductors, causing unbalanced currents which cause stray voltage.

On the customer side, undersized neutrals, poor connections, corrosion in meter fittings, and inadequate grounding may contribute, as can defective or improperly wired customer equipment. Unbalanced customer load can be a cause. Use of 120v rather than 240 volt (US) equipment can contribute. Equipotential planes (wire mesh embedded in concrete floors) bonded to all metal equipment in the barn can help, as required by the National Electric Code for new construction. The potential differences in dairy barns can be due to both the utility system equipment and the farmer's equipment. Most corrections are by fixing the farmer's wiring, not the utility wiring, in general.

This could be merged to an article on power quality, because similar issues of a voltage difference between neutral and the earthed ground conductor, or between the ground conductor and local ground, are common in computer and electronic equipment, in hospital operating rooms, and anywhere equipment or living things might suffer harm from unintended differences of potential. "Touch and step potential" is a similar safety issue around high voltage utility facilities.

Early 19th century telegraph systems used the earth as a return path. Late 19th century telephone companies switched to a metallic return path to reduce interference. Electric utilities do not use the earth as an intentional return path for AC current. I believe some high voltage DC transmission lines have the option of using the earth as a return path is one of the conductors (positive or negative) fails.

Electric and gas utilities apply DC voltage to underground pipes to reduce corrosion, and the earth may be a return path (along with old trolley car rails buried under pavement). A metallic path is provided for return current in AC distribution. Leakage current in customer applications may flow through the ground, and unbalanced loads may result in some current flow to ground. Certainly in faults current flows to ground.

At every pole with a transformer on it and at every pad-mount transformer I have seen there is a ground rod connected to the neutral for safety and to establish a ground reference, and there is a ground to neutral connection to a cold water pipe or ground rod system at the customer's main panel. There is a metallic return path to the transformer. Some current may flow to ground from unbalance or fault conditions.

I have personally experienced shocks from the water from an electric hot water heater in which the heating element was somehow leaking current and the water pipes were nonmetallic. In old houses without grounded outlets I have seen substantial voltages between a range or refrigerator and the cold water pipe of the sink. I expect that a cow would resent the tingle from any voltage difference between the milking machine and the floor of the milking parlor. Establishing equipotentiality between the equipment and anything the cow touches would be critical to a successful dairy operation.

The flow of current and the presence of electric fields on transmission and distribution overhead wires can result in induced currents in nearby metal objects. In radio stations and audio or video production facilities a few volts of difference between the grounds on different outlets have led to hum or "hula" distortion in video which would put them out of business as surely as a dairy farm with upset cows.

Electromagnetic fields surround power conductors and appliances outside and inside the home, and their possible effects on humans have been a topic of debate and academic study since the 1970's, with little evidence they cause cancer or other ailments, but the issue is far from resolved. Edison 15:31, 31 May 2007 (UTC)

(While you have very valuable comments, Edison, your run-on megaparagraph is annoying to read. I have broken it up to make it more legible.) DMahalko (talk) 11:50, 6 February 2009 (UTC)

Grounding to Water pipes is now against code (at least here in New Zealand), because of the risk of live-ifying your water system in case of a fault. I am not a farmer, but I have heard of the stray current issue as in poorly insulated / grounded equipment creating ground currents which upset the cows and cause higher levels of somatic cells in the milk - we have a lot of milking sheds in New Zealand. Egmason (talk) 09:48, 7 July 2016 (UTC)

Okay, so this article has many serious problems. Here's a nitpick (by comparison to the larger problems): Currently it says that some farm in Michigan got measured "stray voltage" of "below one milliampere". Since when did anyone start measuring voltages in amperes ? I find it hard to believe the US supreme court would commit such a physics 101 error. Is there a reference ? --Eivind Kjørstad 15:09, 14 October 2007 (UTC)

Jodie S. Lane

Did she die in 2004 or 2005? Both dates are mentioned in this entry. Pelle79 (talk) 13:38, 19 November 2008 (UTC)

Fixed, 2004 - that's what references are for. --Wtshymanski (talk) 17:03, 7 February 2009 (UTC)

Patent 7,283,055

Cool. Put a light bulb and a buzzer on every single metal object that might get energized. You can get a patent for the darndest things - and you don't even need to hire a draftsman! For the cost of putting these gadgets on, you could put in a big horking copper bonding strap and actually *prevent* the problem instead of just hanging a light on it. pat2pdf.org is *so* useful... --Wtshymanski (talk) 17:03, 7 February 2009 (UTC)

Finallly found a decent source with a good explanation.

I finally found a good source which explains the problem.[1] This is a study for the Ontario Energy Board (marked, amusingly, "Private Information - Not to be Disclosed without the consent of the Ontario Energy Board", but it's on their web site.) The fundamental problem is that the neutral wire in 3-phase distribution systems is not only grounded at more than one point (see ground loop), the neutral on the high side of the transformer is tied to the neutral on the low side. So some fraction of the neutral current will travel through the ground, there can be a potential difference between grounding points, and some of that potential makes it across the distribution transformer. If the load on each phase is balanced, the neutral current disappears, but when the load is unbalanced, there will be neutral current and voltage differences. Ways to measure and deal with the problem are discussed. --John Nagle (talk) 17:21, 4 May 2010 (UTC)

Remarks July 21

This article does raise some good points, particularly in the arena of agriculture facilities. However, consider the following comments: First, the notion that electricity follows the path of least resistance is mostly true. Because the neutral (return path) in North America is bonded with the ground, return current will use the ground as a return path as well. A bonded neutral is required by the NEC to provide a safe, stable electrical network.

Second, voltage and amperage are not interchangeable terms (as noted in the article that stray voltage can be measured in milliamps). Stray voltage should be more correctly called leakage current. Current returns to the source, not voltage.

And lastly, stray voltage cannot be measured accurately with a voltmeter. A voltmeter measures the potential difference between two points. The most often test conducted measures voltage between a building structure and a reference rod. Where the reference rod is placed (i.e. what type of soil, proximity to a utility ground, proximity to a building, resistance of the rod) can result in widely varying figures. The only way to measure for leakage current is with an ammeter to measure the differential between what power is being consumed and what is returning to the source.

This is an informative article on a subject that is poorly understood by many "experts". -- Danmessina4516 (talk) 13:27, 21 July 2010 (UTC)

Induced Voltage

I edited this section to remove several incorrect statements. To start, "induced" stray voltage most often does not refer to current induced per Faraday's Law, but rather to false positive readings given by capacitive test devices. Induced current can be a shock hazard on long fences running underneath and parallel to transmission lines, but this not the understood context of this article., I also briefly detailed techniques used by those in the stray voltage detection and mitigation business to distinguish "induced" voltage from voltage measured between a real source and ground. —Preceding unsigned comment added by PrazanPS (talk • contribs) 16:10, 2 August 2010 (UTC)

References

Revisions 8/2010

Recently, I posted some new material and appreciate the feedback. Some quick points: the IEEE draft definitions are available on the working group website, already cited at the end of the article. I'll add a reference. I agree more information is needed on the pen detectors and e-field detectors. I plan to add this in the future, as well as a separate article on contact voltage. I have two suggestions to make this article better. First, I think the terminology discussion should be right up front. Stray voltage is that, like "smart grid" or other buzzwords, means very different things to different people and this article should address that up front. The IEEE defs are not the only ones; there are others by NEETRAC and by nearly every state commission that has tackled the issue. Perhaps more of these definitions should also be cited. Nevertheless, definition comes first in an encyclopedia in my opinion. Second, I think the "stray voltage on power systems" section ought to be called "stray voltage phenomena" since it is essentially a list of very different phenomena that are frequently placed under the "stray voltage" tent. In fact, elevated neutral voltage in the agricultural context is the real stray voltage and these other conditions are similar but different. In a perfect world, they'd all have their own separate words but language is only as precise as its usage. Feedback and discussion on either of these two issues is appreciated. —Preceding unsigned comment added by PrazanPS (talk • contribs) 14:35, 10 August 2010 (UTC)

DC and "voltage detectors"

My experience is limited, but my Fluke pen won't see 125 V DC or 250 V DC, in actual tests. At least one model of "volt pen" isn't going to detect DC. --Wtshymanski (talk) 21:57, 23 August 2010 (UTC)

Phantom voltage merger proposal

It has been proposed by someone that Phantom voltage and Stray voltage be merged.

• Oppose They are different phenomena. "Phantom voltage" is observed when some conductor shows a voltage into a high-impedance load, like a voltmeter, but there's no significant current behind it. This is usually an inductive problem. "Stray voltage" is typically caused by ground currents between multiple grounding points, and there may be significant current flows. --John Nagle (talk) 19:32, 9 September 2010 (UTC)
• Comment Just this morning I was forwarded a presentation on the death of Danny Cheney, an Australian powerline electrician who was killed by induction-induced currents. Capacitive coupling between conductors also exists and can give sufficient voltage to light a pilot lamp, give a high reading on a voltmeter, or give a false signal to a PLC input. I don't see the need for two articles covering the same phenomenon, and "phantom voltage" is better used to describe "phantom power" in the audio business. --Wtshymanski (talk) 21:17, 9 September 2010 (UTC)

OK, I'm convinced. I now support merger into "Stray voltage". --John Nagle (talk) 18:16, 14 September 2010 (UTC)

Informative diagram

A suggestion has been made to portray the effect of current flow throught the soil from a malfunctioning HV item, E.G. case of a step down transformer used in a electrical distribution substation. If the diagram could explain visually, in simple terms, the logarithmic relationship between distance and current flow through soil.
Like the electrical field strength given off by an R.F. antenna (aerial), the current falls at an inverse square ratio with distance, (as light does from a single point source). For the purposes of the diagram this works in our favo(u)r. A person close the source of stray voltage (the transformer case), the voltage gradient here is so steep as to be fatal. (>50 ma across the heart).
So as to maintain technical credibility, we cannot use underground cable feed into this transformer. The presence of an equipotential cable sheath (to the soil) ) would prevent much stray voltage occuring. One suggestion put forward is to include a graph underneath the picture to visually relate distance and voltage pressure.
This representaion will allow dotted lines to be connected to the ground areas above (in the drawing) and a simple visual relationship will then be observed by the reader.
Use of overhead poles for the incoming (11,000v (u.k.)) and the outgoing (240v /110v), would allow the concrete block, and the transformer on it, to be isolated from the CPC (earth) of the power grid. If a cable connect(x)ion could be added to show that the protective fence around the transformer is equipotentially bonded to both incoming and outgoing (CPC) earths, then the visual image will appear technically correct.
So, to recap, two poles, one ring fence (with open gate), one transformer, 4 people at varying points of the potential gradient, one bringing an external (a water hose has been suggested) into the area, which has the effect of bringing another point of low potential into the area bounded by the fence. help would be appreciated with the necessary line drawings needed. (pole carrying three wires in/out, transformer on base). Francis E Williams (talk) 11:35, 4 December 2010 (UTC)

Definition confusion

I did my best to clean up and consolidate the rather confusing discussion of the definitions of "stray voltage". But it appears that there is a fundamental difference between the 2005 IEEE draft proposal and common usage. Does anybody have any updates since then, or useful insights? Reify-tech (talk) 22:56, 2 June 2011 (UTC)

how about intentional stray voltage placed upon humans

any cases? — Preceding unsigned comment added by 173.62.160.246 (talk) 00:54, 14 April 2017 (UTC)

Where does the current return in the first image?

In the first image/figure/diagram of this article, its caption says "A fallen power conductor from a transmission line forces current through the earth [...]" While I understand that phrase as saying that current travels from the transmission lines to the earth, my question is: at which point does the current return to the electrical grid (power system)?

If it's not returning, then are you saying that AC current can flow in open circuits? --Alej27 (talk) 05:44, 13 November 2020 (UTC)

Whenever I find myself answering a question like this with "Everybody knows that....", it's usually a sign we've left something out of the article. I changed the illustration caption, have a look at it now. It reads clumsily to me, which is probalby why this was left out initially. --Wtshymanski (talk) 18:31, 13 November 2020 (UTC)

Thanks for the clarification. I think the caption is better now, but if you think otherwise you can of course revert your edit. Thanks again. --Alej27 (talk) 06:25, 14 November 2020 (UTC)