Previous in Forum: R Square of Resistive Cloth   Next in Forum: MCCB Calculations
Close
Close
Close
40 comments
Associate

Join Date: May 2008
Posts: 39
Good Answers: 1

Electrified Cows

03/19/2009 5:58 PM

Stray voltage is devastating my neighbors' dairy cows. Joe the neighbor is asking my assistance and after searching CR4 and Google, I find mainly that, 'Yes, Virginia, it is a problem', but I don't see many potential solutions.

Joe the neighbor has a standard single phase 220V/110V service to his rural farm in the Midwest, USA. His power is supplied to him via a 7200V AC, 2-wire overhead line and a pole mounted step down transformer at the street. There is a 400KV DC transmission line within 3 miles but I doubt it has anything to do with stray voltage.

I asked if he had checked the obvious;

Check for loose connections on the neutral and ground on his service panels.

Shut off all power, turn on one disconnect switch at a time and try to isolate the problem down to a specific circuit.

Check his cattle containment electric fencer for proper installation.

He claims to have already done these things as well as sinking a 40ft ground rod into the ground water, trenching in a ground wire around the perimeter of the building site and bonding them together. Joe is not even sure if the voltage originates at his farm or just travels through his area. The REA Utility Company claims no responsibility and offers no assistance.

My questions are;

How does one find stray voltage, where does one start and what type of meter works best?

Would an isolation transformer feeding his milking parlor be beneficial or would this essentially function the same as the street transformer that converts the 7200V to 220V?

Would there be any advantage to converting everything possible to run on 220V so no power returns on the neutral as it does with 110V? Does any power actually return through the ground to the original Utility Companies generator? The REA says no.

Any other ideas for potential solutions like how to change the impedance of a cow? If we fit them with special tennis shoes we'll probably run into some new strain of bovine athletes foot problems.

I understand the stray voltage does not actually hurt the cow but sets up psychological avoidance behaviors which affects its health and makes them fearful and nervous which affects milk production. Does anyone know how to modify the behavior of a cow so it becomes immune to stray voltage, or teach it that electricity could actually be a calming device?

BTW this is NOT a homework assignment (actually, I guess it is!).

__________________
The beatings will continue until morale improves.
Register to Reply
Pathfinder Tags: cattle Cow Stray Voltage
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: El Lago, Texas, USA
Posts: 2640
Good Answers: 65
#1

Re: Electrified Cows

03/19/2009 6:24 PM

Maybe an electric field meter?

http://www.lessemf.com/electric.html

If it doesn't help the cows you can also use it to play Ghost Hunters.

Register to Reply
Guru

Join Date: Feb 2009
Location: West Coxsackie, NY
Posts: 533
Good Answers: 10
#2

Re: Electrified Cows

03/19/2009 6:58 PM

What indicators lead you suspect stray voltage is the problem?

__________________
"Real Bass Players" do not use picks
Register to Reply
5
Guru
Australia - Member - New Member

Join Date: Feb 2008
Location: Australia
Posts: 2131
Good Answers: 251
#3

Re: Electrified Cows

03/19/2009 7:03 PM

A little more information please.

Is this only happening in his milking shed? or elsewhere on the property?

You need to check for both AC and DC potentials, so when you measure, be sure to check both situations.

An AC value would indicate something relating to power supply/earthing/neutral issues.

A DC value would point towards other causes.

You indicate that the apparent voltage is relatively small, but if it's in the dairy room and especially when the milking cups are being attached to the cows nipples/teats (Highly sensitive) it would not require a significant voltage.

So what type of dairy is it? Rotary, walk in stalls or herringbone or some other.

If the environment is relatively dry (or there are dry insulation zones) then a possible source of DC is the vacuum system. One way air flow creating a static build-up on the system. so check for electrical AC/DC potential on the vacuum lines.

Another potential source is galvanic effect of the various parts of the yards and stalls. Check electrical potential (AC and DC) from anything the cow can touch relative to a wet puddle on the floor. Check for electrical potential from the vacuum lines.

Another possible source would be any flow sensors in the cups. (if it's a "modern" dairy)

Does the switchboard have earth leakage protection? If so, then it's unlikely that the fault is relating to power supply.

Is there a radio in the room? (What does it use for an antenna? I've seen bare copper wires wrapped onto yard rails to improve reception.)

Hope these ideas help.

__________________
Just an Engineer from the land down under.
Register to Reply Good Answer (Score 5)
Guru
Brazil - Member - New Member Engineering Fields - Mechanical Engineering - New Member Hobbies - RC Aircraft - New Member Hobbies - Target Shooting - New Member Hobbies - Automotive Performance - Hey there... interested in exchanging information about car performance? Hobbies - DIY Welding - New Member

Join Date: Jan 2007
Location: Porto Alegre - RS - Brazil 30deg01'39.73"S 51deg13'43.45"W
Posts: 831
Good Answers: 28
#4

Re: Electrified Cows

03/19/2009 7:44 PM

...and, if it's indeed stray voltage problem, check all the electric installation and check if he doesnt have a ground loop somewhere. This is usually the most common cause of the problem. Neutral from power supply MUST be grounded only in the power supply inlet. All other grounds, equipment housings, and anything that could be considered a source of grounding must be isolated from the neutral. May even be connected to the same ground as the neutral is, but do it only in that same point.

__________________
Humm... suspicious you are...
Register to Reply
4
Guru
Canada - Member - If there is a way to screw someting up, there is someone to do so! Safety - Hazmat - New Member

Join Date: Mar 2007
Location: Iqaluit, NU. Canada
Posts: 1852
Good Answers: 140
#5

Re: Electrified Cows

03/19/2009 9:00 PM

This is a pretty common problem seen by many electricians who work in rural dairy areas of both Canada and the US. Unfortunately few of them know how to address it. Here are a few hints and tips.

The problem is similar to that of a "step and touch voltage" that workers who work in High Voltage switch yards know about and are trained to react to.

The voltage gradient that can be present, based on different ground resistance can be deadly in the case of a high voltage fault to ground inside a sub station.

The EUSA (Electrical Utility Safety Association) teaches workers to slide their feet and to take very small steps inside a switch yard to extricate themselves fro the danger area during a fault event. The difference in resistance between "foot a" location and "foot b" location can be enough to kill during such an event.

This issue is the same thing only on a much smaller scale. The locations here are... the "ground" and the floor of the barn/milking parlor. Unfortunately, cows are amongst the most sensitive animals on the planet to "tingle voltage".

A few questions... where is the ground for the farm service established?

Does he have a second panel fed from the main service at the barn/milking parlor?

If there is a second panel, does it have its own grounding electrode, that is connected, through the neutral, tied back to the main service grounding electrode?

You asked about an isolating transformer, it may help but only if the neutral is carrying current back to the source from outside of the property. In this day of the utilities using "Y primary and Y secondary" distributions, this problem is going to be seen more and more.

Normally the grounding electrode connection to the neutral must be solidly done at the primary service, there are provisions in the Canadian code that allow for a device, see CEC rule 10-204(1)(b), specially designed to address the issue you have brought up. It is called a "tingle filter". Here is a link to a OMFRA (Ontario Ministry of Food and Rural Affairs) web site with lots of data on this issue.

http://www.omafra.gov.on.ca/english/livestock/dairy/facts/strayvol.htm

__________________
Joe Contractor to Electrical Inspector, "What do you mean you are going to make me follow the code?".
Register to Reply Good Answer (Score 4)
Guru
Canada - Member - If there is a way to screw someting up, there is someone to do so! Safety - Hazmat - New Member

Join Date: Mar 2007
Location: Iqaluit, NU. Canada
Posts: 1852
Good Answers: 140
#6

Re: Electrified Cows

03/19/2009 9:07 PM

Converting everything to 220 would be a step in the right direction as it reduces current returned to the source via the neutral and reduces the voltage gradient between the "ground" and the neutral/bond system.

My comments about the utility "Y primary and Y secondary" talk to your next question. Yes.. if the impedance back to the source is less at your friends place then the impedance of the system at his neighbour (unlikely but very possible - I have seen it before) his system will return current for his neighbour back to is source, even if it is on a different distribution transformer, if the utility has a common neutral.

__________________
Joe Contractor to Electrical Inspector, "What do you mean you are going to make me follow the code?".
Register to Reply
Power-User

Join Date: Jun 2008
Location: Olive Branch, Ms. USA
Posts: 124
#7

Re: Electrified Cows

03/19/2009 10:43 PM

Since this is in the Midwest check the water tank heaters. I was sent on a call in Iowa many years ago anf found a pig farmre had wired tank heaters in without a ground and killed all of his pigs.

__________________
Tell 'em what they need to hear; not what they want to hear!
Register to Reply
Member

Join Date: Mar 2009
Location: Wisconsin, USA
Posts: 8
Good Answers: 1
#8

Re: Electrified Cows

03/20/2009 11:09 PM

This is a problem in Wisconsin as well. http://www.wisconsinpublicservice.com/farm/stray.aspx This is a pretty fair primer on stray voltage.

I don't know what state you're in, but most should have a board to deal with stray voltage issues. Perhaps the state university or local electrical trades would be a contact point.

As for training cows to like shocks, I haven't heard of to many masochistic cows. Do any of the neighboring farms have problems, and what have they found out? Is there a co-op in the area, they would likely have more specific information for your area.

Register to Reply Score 1 for Good Answer
Power-User

Join Date: Sep 2007
Location: Sheboygan, WI USA
Posts: 372
Good Answers: 13
#9

Re: Electrified Cows

03/20/2009 11:42 PM

A very good contact is:

Stetzer Electric, 520 W Broadway St, Blair, WI 54616 Tel: 608-989-2571 Fax: 608-989-2570

They have successfully troubleshot the cow problems related to electricity.

__________________
"I believe we are masters of our lives - we hold all the cards and it is up to us to use them right." Vesna Vulova - survived 33,000ft fall
Register to Reply
Guru
Popular Science - Cosmology - Let's keep knowledge expanding Engineering Fields - Retired Engineers / Mentors -

Join Date: Dec 2006
Location: North America, Earth
Posts: 4358
Good Answers: 104
#10

Re: Electrified Cows

03/21/2009 12:17 AM

Hi Age>IQ,

"I understand the stray voltage does not actually hurt the cow but sets up psychological avoidance behaviors which affects its health and makes them fearful and nervous which affects milk production."

I would start by herding the cows around the farm to find out what they are afraid of. Whatever they are afraid of is the place to look. Otherwise you can waste a lot of time going nowhere. It could be an induced voltage from the overhead lines.

Maybe having an electric containing fence is not the best idea. My dad used one when he wanted the cows to clean out the irrigation ditch, and to keep them away from the alfalfa. He had an old cow (about 12 years old) that would wait for one of the young heifers to get broadside to the electric fence then charge her to knock down the fence without getting shocked herself. Once the fence was down, there was nothing to stop her from eating the alfalfa.

S

__________________
“I would rather have questions that can't be answered than answers that can't be questioned.” - Richard Feynman
Register to Reply
Guru

Join Date: Oct 2007
Location: Zagreb, Republic of Croatia (native name Hrvatska) ,EU, Europe
Posts: 545
Good Answers: 8
#11

Re: Electrified Cows

03/21/2009 2:03 AM

Yes, it would be better to have just 220V system only, as two systems can react because of potential difference.

But real question is: How does Mr. Joe know it is >>stray voltage<< that is bothering his cows? From where was this conclusion drawn?

Dry grass can generate static electricity, and so can carpets or other floor covering...

I dont believe in story of electricity traveling back to electric central, as where would electric charge from thunderbolt that strike mountain or a tree and went to ground go?

Is it really true that there is 400 KV DIRECT CURRENT line still in use, when this is very ineficcient pover transmision system that was replaced by AC just because of great loss of power in such lines?

Anyhow, wet wall and wire nibbled by mouse can be source of electricity leak, so each circuit should have its own fuse, then one can test them one by one to see if meter is turning even when nothing is switched on. If it is line activated only when light is turned on, then each place should be tested on drop in voltage on light bulb wire.

Badly installed wires can drain electricity from one another if there is not enough insulation between them, but this need not leak otherwhere but is simply lost, at least that was story I heard from one old professionall electrician....

Last of all, I seems to remember that this same problem was discussed on some thread before, so better try to find it so we dont duplicate efforts.....

__________________
Per Aspera ad Astra
Register to Reply
Guru

Join Date: Jun 2006
Location: Ottawa Canada
Posts: 1975
Good Answers: 117
#12
In reply to #11

Re: Electrified Cows

03/21/2009 6:57 AM

Why would a 400 KVA direct current line be less efficient? Of course, I don't know what a 400 KVA transmittion line would look like...I suspect it might be a 400 KV line. (Though that does seem awfully high.) If it was a 400 KV transmission line, then ohms law would allow very little current to flow, and therefore very little voltage drop, and very little loss. One amp in fact. If it was only half as hot, you would get two amps flowing. Still, not a lot of potential for loss.

Of course, if we are looking at 400 volts, you would need to push a thousand amps. That would be pretty lossy. My point? I don't see what there is about high voltage DC which would make it inefficient.

Oh well. No doubt there is something I don't know about this.

__________________
If it was easy anybody could do it.
Register to Reply Off Topic (Score 4)
Power-User

Join Date: Mar 2009
Location: O'er looking the silvery Tay
Posts: 255
Good Answers: 18
#13

Re: Electrified Cows

03/21/2009 7:25 AM

Hi ''hot cows''

I came across this problem some 40 years ago on a remote piece of territory on the west coast of Scotland. Again the cows were getting 'jumpy' in the vicinity of an overhead nine pole supporting a transformer supplying several houses and a small farm stead from a 3.3kV single phase supply. There was a history of 'peculiar' things happening on the local supply network and a variety of equally bizarre explanations prevailed. My father an experienced electrical engineer suggested that the cause was due to substantial current flows in the earth return in the area. The local electrical supply authority , South of Scotland Elcrtricity had a stock solution to overcomig hot spots by installing ELCBs on the main incomer to each property considered as contributing to the problem. The key issue was that the troubled bovines only experienced the problem near to the pole where the the transformer was fixed and the trouble got worse in wintertime when the ground was really wet. Clearly the conductivity path was an important factor. No one ever measured the potential between the front and rear ends of the coos but they are probably more sensitive than we think!

Clearly the is an issue with the local installation which would become aparent if an ELCB was fitted as it would trip before the earth current got to a level sufficient to manifest itself in the 'hot cow syndrome.

Therfore sart by doing an insulation test on all the connected wiring and things like motors which may well have developed a significant fault to earth.

__________________
If it ain't broke,leave it well alone .........until it comes looking for you!
Register to Reply
Associate

Join Date: Jun 2007
Location: Lexington, Kentucky, USA
Posts: 33
#14

Re: Electrified Cows

03/21/2009 8:59 AM

I can point you to a couple of places to start your search. First contact you local cooperative extension service they will have some resources at your state agricultural engineer school which will give you some assistance in testing.

Here are some links to information about stray voltage in diary barns.

http://www.mwps.org/index.cfm?fuseaction=c_Products.viewProduct&catID=712&productID=6129&skunumber=NRAES-149&crow=1

http://edis.ifas.ufl.edu/AE019

http://www.egr.msu.edu/age/aenewsletter/1_jan_feb_03/tinsey_1_30.htm#2

Finding the source of stray voltage can be difficult and will take some effort to track down.

Best of Luck, Mike

__________________
"A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away." Antoine de, Sant-Exupery
Register to Reply Score 1 for Good Answer
Guru

Join Date: Oct 2007
Location: Zagreb, Republic of Croatia (native name Hrvatska) ,EU, Europe
Posts: 545
Good Answers: 8
#15
In reply to #12

Re: Electrified Cows

03/21/2009 9:22 AM

Here is excerpt from Wikipedia:

------------------------------------------------------------------------------

Main article: History of electric power transmission New York City streets in 1890. Besides telegraph lines, multiple electric lines were required for each class of device requiring different voltages.

In the early days of commercial use of electric power, transmission of electric power at the same voltage as used by lighting and mechanical loads restricted the distance between generating plant and consumers. In 1882 generation was with direct current, which could not easily be increased in voltage for long-distance transmission. Different classes of loads – for example, lighting, fixed motors, and traction (railway) systems – required different voltages, and so used different generators and circuits. [7]

Due to this specialization of lines and because transmission was so inefficient that generators needed to be close by their loads, it seemed at the time that the industry would develop into what is now known as a distributed generation system with large numbers of small generators located nearby their loads. [8]

------------------------------------------------------------------------------------------------------------------

I took liberty to make part of text bold......

I wrote answer to You before going to check at WEB about DC but this text simply dissapeared, but now I shall not repeat myself, sorry.

__________________
Per Aspera ad Astra
Register to Reply Off Topic (Score 5)
3
Power-User

Join Date: Sep 2007
Location: Sheboygan, WI USA
Posts: 372
Good Answers: 13
#16

Re: Electrified Cows

03/21/2009 9:44 AM

A couple more ideas -

If there is arcing, it will produce radio interference, using a cheap handheld battery powered AM radio walk thru the areas that have electricity, a car radio if you are driving along the road. Listening to a place on the radio band without a station, you will hear the noise increase as you approach the source. If there is arcing on the utility HV side it can be causing radio interference for a mile around. You will also see this as stripes across a analog TV screen using a rabbit ear antenna, there will be two stripes usually rolling up the screen, one at the top when the other is in the center (TVis 30 cycles and power is 60 cycles). This arcing can also be random, dependent upon when the arcing is occurring. I had this happen in 2004 in rural central WI.

Lightening and gunshots change things, lightening can flash over insulators, a common insulator design installed years ago here in WI is a common distribution voltage fault. The utilities don't look for defective insulators unless there is a problem, other then the radio-TV interference it causes. What this defective insulator does can be intermittent to continuous arcing shorting the utility HV to the pole and into the earth. If this is bad enough it can cause an outage without indication of where the problem is, the top of the pole was burnt from lightening.

There is also a fuse holder that is a utility problem, it starts to conduct between the utility hot and the mounting bracket to the pole, it can also cause outages when it rains. The conduction between the utility hot and the mounting bracket to the pole can be seen with an infrared camera. One Midwest utility found hundreds of these fuse holders with the problem using an infrared camera, I have seen it as far away as Halifax, Nova Scotia back in 2000.

In the spring in the Upper Midwest there are also pole fires caused by an accumulation of road salt during the winter, this is more common in the cities, Madison WI had 5 pole fires one day, other cities have had more, along one highway south of Indianapolis they replaced the wood poles with steel or concrete.

Sometimes due to the wind loads the tie wires holding the power line to the top of the insulator break and the power line lays on the wood cross arm, and if dry there may not be a fire until...it rains or gets humid or fog, but in the meantime the electricity is leaking to a ground return somewhere.

Along the oceans salt fog can create the same problem as road salt in contaminating insulators and rotting out the steel support cable inside conductors, causing the conductor to break and fall to earth. This has also happened in central WI on a69kV line.

I would also mention Stetzer Electric have some info if you search there website

http://www.stetzerelectric.com/filters/research/

The American Transmission Company website also has info www.atcllc.com they supply all electricity above 69kV in WI.

I remember "Nellie" she was a big cow, and every time I went to get the cows home for milking, Nellie ran the other way, thru fences and all. If I was in the barn she was always looking for me, the farmer milked by hand and I left the barn so he could milk Nellie his best producer. Who knows what cows remember or why they act as they do.

And years ago there were farmers daughter jokes all the time, where did they go ?

__________________
"I believe we are masters of our lives - we hold all the cards and it is up to us to use them right." Vesna Vulova - survived 33,000ft fall
Register to Reply Good Answer (Score 3)
Associate

Join Date: May 2008
Posts: 39
Good Answers: 1
#17
In reply to #3

Re: Electrified Cows

03/21/2009 10:26 AM

Thanks for your response. You have given us a lot of fodder for experimentation.

We aren't certain exactly where the problem is. He is asking how to trace these types of voltages, and I'm not certain where to start. We are just assuming it's a small voltage as that is typically all it takes to affect a cow.

__________________
The beatings will continue until morale improves.
Register to Reply
Associate

Join Date: May 2008
Posts: 39
Good Answers: 1
#18
In reply to #5

Re: Electrified Cows

03/21/2009 10:37 AM

Thanks for all the good information.

He has separate panels in the house and in the milking parlor that are on the same service. It is typical to separately ground each service but I know he drilled a forty foot well and used it as his main ground. He has also bonded the services and a trenched in perimeter ground wire to this main ground.

__________________
The beatings will continue until morale improves.
Register to Reply
Guru
Canada - Member - If there is a way to screw someting up, there is someone to do so! Safety - Hazmat - New Member

Join Date: Mar 2007
Location: Iqaluit, NU. Canada
Posts: 1852
Good Answers: 140
#19
In reply to #18

Re: Electrified Cows

03/21/2009 10:52 AM

From your comment it appears that both panels are bonded. Here is a reference drawing. Get him to check and make sure his panels are setup like this.

__________________
Joe Contractor to Electrical Inspector, "What do you mean you are going to make me follow the code?".
Register to Reply
Associate

Join Date: May 2008
Posts: 39
Good Answers: 1
#20
In reply to #11

Re: Electrified Cows

03/21/2009 10:52 AM

Thanks for your response.

Yes it is a 400KV DC line. That's why assume no induced voltage from a DC line.

When this DC line was proposed and installed back in the 1970's the farmers in this area opposed it passionately, claiming their would be stray voltage. They wouldn't listen to the fact that you get no induced voltages from a DC line. They would stage protests and even pull down towers with their large tractors. The power line zig zags through this area as you can see the planners had to follow the farmers path of least resistance. I recently asked an old fellow, that was strongly and actively opposing it back then, what was really the main issue and he said they wouldn't pay the farmers enough for the tower sites.

__________________
The beatings will continue until morale improves.
Register to Reply
Associate

Join Date: May 2008
Posts: 39
Good Answers: 1
#21
In reply to #16

Re: Electrified Cows

03/21/2009 10:56 AM

Thanks for all the good tips. I will be certain to try some of these.

__________________
The beatings will continue until morale improves.
Register to Reply
Guru
Canada - Member - If there is a way to screw someting up, there is someone to do so! Safety - Hazmat - New Member

Join Date: Mar 2007
Location: Iqaluit, NU. Canada
Posts: 1852
Good Answers: 140
#22
In reply to #11

Re: Electrified Cows

03/21/2009 11:03 AM

Hi Henrik14

You said...

"I dont believe in story of electricity traveling back to electric central, as where would electric charge from thunderbolt that strike mountain or a tree and went to ground go?"

Well... It happens all the time. Current will return to its source via every path that exists.

Notice I said "source" not "central". It happens quite frequently where we loose a bunch of consumer neutrals due to weather events and return current (from the unbalanced current of a consumers draw) will be carried by a ground return to the nearest pole ground then back to the common utility neutral, which is common to both the primary and secondary sides of the distribution system.

We burn poles this way quite often in some of our communities, as mentioned by another poster.

As far as the energy from a lightening strike is concerned, the earth itself is the return point so there is no where else for the current to flow to.

__________________
Joe Contractor to Electrical Inspector, "What do you mean you are going to make me follow the code?".
Register to Reply
Active Contributor

Join Date: Nov 2007
Posts: 11
#23

Re: Electrified Cows

03/21/2009 12:36 PM

Check with your power company. Stray voltage has been a issue for some farmers in Wisconsin. There was a law suite against WPS many years ago by our neighbor. He received a large settlement and is still milking cows (4600 of them).

Google: Wisconsin public service stray voltage

Below is one of the many sites that came up.

http://www.wisconsinpublicservice.com/farm/stray_overview.aspx

Good Luck and don't take any BS from the Electric Company in your persuit of justice.

Register to Reply
Guru

Join Date: Mar 2008
Location: Sebring, Florida
Posts: 923
Good Answers: 25
#24

Re: Electrified Cows

03/21/2009 1:27 PM

I really think that you have isolated the source of your problem in a single line in the thread posting.

"The local REA Claims No Responsibility, AND: offers No Help!"

This issue was reported many years ago in an article that I read about the stray voltage associated with transmission lines that was adversely impacting a dairy farm. As can always be anticipated the local Utility Monopoly, be it an REA, or A Co-OP, or any other Monopoly, their first line of defence is is denial. Their Legal Advisers will always advise them to "Make You PROVE that their equipment is RESPONSIBLE for your losses. This can sometimes be a lengthy and costly effort. You can bet that if they find that you are getting close to proving that their equipment is the problem, they will very quickly begin making corrections that will impede your ability to hold them financially responsible for the problems that they cause. It is all about the money.

One way to isolate the problem is to bring in a standby generator source for your electrical power and have the REA disconnect the wires at the pole by the public right of way.

Make absolutely sure that it is properly grounded. If the problem continues in the milking barn, "and there only", you may find that the problem is the concrete floor not being sufficiently grounded.

These floors will have steel rebar throughout below the surface, but these surfaces will have microscopic cracks that will allow moisture to penetrate and said moisture will conduct current to the rebar and on to ground via the least restrictive route, through the wet cow and the wet equipment. Every milking barn I have been in has the cow restrained in the milking stall by some sort of metal bars, with the cow munching on wet silage, standing on a wet concrete floor, and connected to a metal "conductive" electric milking machine. When one considers the many avenues for positive current to flow to ground in this environment, isolating one from the other can be a time consuming problem.

In the end it was found that stray voltage from the utility was the problem! The Dairy Farmer prevailed in court, but to do so he had to prove that there was absolutely no other source electricity getting to the cows causing the problem!

Good Luck!

TooMuchFun

__________________
The only problem with common sense, is that not very many people have it, or know how or when to use it.
Register to Reply Score 1 for Good Answer
Guru

Join Date: Jun 2006
Location: Ottawa Canada
Posts: 1975
Good Answers: 117
#25
In reply to #15

Re: Electrified Cows

03/21/2009 1:35 PM

Ah well, that would be for low voltage applications then. You should have highlighted the line that said "transmission of electric power at the same voltage as used by lighting and mechanical loads restricted the distance." That was then. I believe it is still much more efficient to send power by DC at Very High Voltages.

AC will transform a lot easier, thats true. However, 120 times a second, it approaches zero. This causes a lot of loss.

But Wikipedia is pretty cool. this is what Wikipedia has to say about HVDC

A high-voltage, direct current (HVDC) electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current systems. For long-distance distribution, HVDC systems are less expensive and suffer lower electrical losses. For shorter distances, the higher cost of DC conversion equipment compared to an AC system may be warranted where other benefits of direct current links are useful.

One big savings of course is the fact that with HVDC, you don't get a lot of inductance losses. And therefore a little less likely that there would be stray voltages affecting the cows.

__________________
If it was easy anybody could do it.
Register to Reply Off Topic (Score 4)
2
Guru

Join Date: Jan 2007
Location: Sitting directly behind my keyboard in Albuquerque - USA
Posts: 592
Good Answers: 19
#26

Re: Electrified Cows and Swimming Pools

03/21/2009 2:29 PM

Not sure if this will help, but I had to help a pal who owns an aquatic club to fix small shocks swimmers were getting whilst they touched cleats, handrails, and the metal side rails and clips for a liner type pool. All grounding mentioned here was made with bare copper number 6 wire and exothermically welded to ground posts and to each other and all connections. All rails, cleats and metal pieces were bonded by welding tabs on them below grade (chipping out concrete). I pounded in several ground rods more than 8 feet apart in 4-5 places outside. I removed the pool liner and sliced a checker board grid in 1 meter squares into the bottom and up the sides with a stone saw and pounded in the number 6 wire, grouted it in place. Where the wires crossed I welded them with a kit for this purpose (see here). I busted out concrete around the walkway and tied into the concrete screen in 10 places. I tied into the rebar of the footing to make a Ufer Ground. So basically, everything someone could touch, walk on, or swim above was grounded together and tied into the 5 ground rods. When done, I checked it all with a clamp on ground resistance meter. It took two of us a week. This is an equipotential grid. No shocks in 5 years.

Maybe 1-2 ideas can be used here, or, teach the cows to swim in the pool.

__________________
If it eats, it's going to be trouble!
Register to Reply Good Answer (Score 2)
Anonymous Poster
#27
In reply to #19

Re: Electrified Cows

03/21/2009 9:50 PM

I must disagree with the drawing above.The NEC stipulates that a sub-fed panel shall not have the neutral (grounded) conductor bonded to the grounding (green) conductor at the subfed panel.This can create ground loops.It shall be bonded only at the main panel.Reference NEC article 547.9.

Also, a separate grounding conductor shall be run with the current carrying conductors.The grounding conductor must be of equal current carrying capacity as the largest current carrying conductor.The grounded(neutral)shall not be connected to the ground rod or panel at the sub panel.

The drawing above is not very clear, but I do not see a grounding(green) wire from main to sub fed panel.---------SSB---------------

Register to Reply
Guru
Canada - Member - If there is a way to screw someting up, there is someone to do so! Safety - Hazmat - New Member

Join Date: Mar 2007
Location: Iqaluit, NU. Canada
Posts: 1852
Good Answers: 140
#28
In reply to #27

Re: Electrified Cows

03/21/2009 10:31 PM

As I am not an expert on the NEC, I will not argue with your statements other then to say...

I agree with you that a sub panel should be fed in the way you mention, if it is in the same building as the service feeding it.

The diagram I presented is expressly for a feed to an out building from a main building and is based on the Canadian code and is the suggested way of feeding an outbuilding when the outbuilding is to house livestock.

As to the missing bond wire you mention, when you ground the neutral at the second building, the bonding conductor is not required in the feed as you recreate the start of the bonding system at the neutral/ground interface at the second panel.

Here is the other way to do this, again based on the Canadian code and not for use in a building that houses live stock. This might look more like what you expected.

__________________
Joe Contractor to Electrical Inspector, "What do you mean you are going to make me follow the code?".
Register to Reply
Power-User

Join Date: Sep 2007
Location: Sheboygan, WI USA
Posts: 372
Good Answers: 13
#29
In reply to #11

Re: Electrified Cows

03/21/2009 10:57 PM

There is a 700km long 400 kvDC transmission line into Winnipeg, Manitoba as a hub. From Winnipeg the line goes to Duluth, MN USA. Another leg from Winnipeg continues down into Iowa / Nebraska.

So there is a lot of farmland under the DC transmission line.

In Quebec Provine, Canada and in Ohio / West Virgina USA there are 735 / 750 KvAC transmission lines.

In Japan there is an 1100 kVAC transmission line, there is a line of this voltage or higher planned in China. The powerline in Japan has an elevator on the towers to get workers up to the top. The towers in Japan have shielding lines between the towers to reduce the electric field intensity at ground level. The shielding lines help to reduce the required height of the towers. Other voltages mentioned above typically do not have shielding wires below the lines.

Nearly all transmission voltages have shielding wires above the transmission lines to reduce lightening damage.

There is one section of 345 kV AC transmission line in central Wisconsin that on one phase for 5 towers in a line the center ceramic insulator in the string of maybe 30 insulators was damaged, only lightening could have done this. There is a splice connector with corona and arcing sometimes in that section of line. I have watched it for most of 8 years. The neighbors across the highway said the top of the tower had glowed one night. The towers are next to a wet, marshy area so very good grounding, about 1/2 mile from a minor substation.

__________________
"I believe we are masters of our lives - we hold all the cards and it is up to us to use them right." Vesna Vulova - survived 33,000ft fall
Register to Reply Score 1 for Off Topic
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 22640
Good Answers: 410
#30

Re: Electrified Cows

03/22/2009 1:16 PM

Age > IQ:

Public Service providers such as WPS (Wisconsin Public Service) is spending millions for this,

The cause is varied, some farmers took the provider to courts and actually won if you want to call it that, Attorneys are the only winner, while the farmer watches his herd get devastated.

As far as stray voltage, on an existing facility (barn) is difficult. Newer buildings they try to ground everything, Stanchions, building steel, milk lines, water lines, ect.... Problem is, As little as 2 volts is enough to effect a cow.

Allot of the stray voltage can not be traced to the source. Work with the service provider, and get in contact with the county extension agent, or field man where the milk is being shipped to.

And you cannot train the cows to except it, because its a form of torture.

Try to identify the source and fix the problem.

Good luck,

phoenix911

__________________
“ When people get what they want, they are often surprised when they get what they deserve " - James Wood
Register to Reply
Anonymous Poster
#31

Re: Electrified Cows

03/22/2009 7:12 PM

I suspect you will find somebody has gone and dug up the copper rods the power utilities use for there earth grid. they can stretch for miles. You can work out which power station as when the cows cark it they are all pointing toward the power plant (coz the voltage lengthwise is more that acrosswise). If the problem is just dodgy milk production you might have to watch the cows carefully and see which way they look uncomfortable...

You could place two rods in the ground and run a wire between looking for voltage and by moving in a circular direction work out where the voltage derives from.

Or go question your local non-ferrous metals scrap yard people as to who has been in with copper rods!

Register to Reply
Power-User

Join Date: Sep 2007
Location: Sheboygan, WI USA
Posts: 372
Good Answers: 13
#32
In reply to #31

Re: Electrified Cows

03/22/2009 7:28 PM

I can't remember which town in I was driving thru, but here was a guy walking down the street with an armload of copper bus, as if from high power switchgear.

__________________
"I believe we are masters of our lives - we hold all the cards and it is up to us to use them right." Vesna Vulova - survived 33,000ft fall
Register to Reply
Participant

Join Date: Aug 2008
Posts: 1
#33

Re: Electrified Cows

03/23/2009 8:57 AM

dont have an answer to the cow problem, but i have heard of this problem ever since i was a kid . although recently i stumbled across an article about a fellow who discovered that cows all over the globe seem to mostly position themselves in a north / south , head to rear direction while out in the pasture. i think he kinda stumbled onto this while working on sattelite imagery. i wonder if the amish folk have any home spun remedys out in the barn ?

Register to Reply
Anonymous Poster
#34
In reply to #11

Re: Electrified Cows

03/23/2009 10:48 AM

Your statement that AC is used over DC for power transmission is true. The irony is that AC has more voltage drop. This is because AC causes eddy currents (Lenz's Law) which force the current flow to the outside of the conductor (skin effect). The reason we use AC is because we can use transformers to step-up the voltage (reducing current and thereby reducing voltage drop) and then step-down the voltage close to the load. Special modern transmission systems can create high voltage DC for transmission which is very efficient because there are no eddy currents and the entire conductor is used!

Register to Reply Score 1 for Off Topic
Member

Join Date: Apr 2008
Location: British Columbia, Canada
Posts: 7
#35

Re: Electrified Cows

03/23/2009 12:24 PM

We came across a similar problem, except that it was a 'tingle' voltage from the water in a hot tub to the ground. In our case the rural customer in question located near the start of a long single phase lateral. The rural subdivision had a common well for a few homes that provided a good return path for the neutral. The effect of the long radial line is that there is a return current in the neutral (it gets "balanced" when it joins back up with the 3phase neutral, assuming it's a fairly well balanced system), and consequently there was a potential difference between the system neutral and the return path through the earth. We unbonded the neutral of the secondary transformer to correct this. If lightning is an issue, there is a device called a "wronk(sp?) reactor" to bond the secondary transformer to ground to protect it. Hope this helps.

Register to Reply
Commentator

Join Date: Jun 2008
Posts: 80
Good Answers: 5
#36
In reply to #27

Re: Electrified Cows

03/23/2009 1:41 PM

Exactly, you can also reference NEC article 250.24 (A)(5) which states "A grounded conductor shall not be connected to normally non-current carrying metal parts of equipment, to equipment grounding conductor(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article." What this is saying is the neutral must be "floated" (not grounded), at all points except at the service panel. This is typical farmer action, hook up whatever you want, however you want, then blame someone else. especially the utility. If you are doing a real investigation, and I am not sure that you are, I would suggest compliance with NFPA 70 should be your first priority. If you do not understand NFPA 70, as is apparent in the posts you have made, perhaps you should turn the task over to someone who does.

Register to Reply
Guru

Join Date: Mar 2008
Location: Sebring, Florida
Posts: 923
Good Answers: 25
#37
In reply to #36

Re: Electrified Cows

03/23/2009 2:27 PM

Isn't it amazing just how many do it yourselfers look into the service panel and see the neutral buss anchored to the panel and also see the ground buss anchored to the panel and believe that these are treated the same through out the wiring system and are therefore inter mixable. I can't imagine how often we see the bare or green ground connected to the neutral buss. It can work but how often do the installers get confused and mix them up. Maybe this farmer should consider installing GFI"s through his entire system. We know for certain that dairy barn floors are almost always wet either from scours,urine or just hoseing down for cleanliness.

TMF

__________________
The only problem with common sense, is that not very many people have it, or know how or when to use it.
Register to Reply
Guru
Hobbies - DIY Welding - pipewelder

Join Date: Apr 2007
Location: North Georgia, USA
Posts: 671
Good Answers: 33
#38
In reply to #5

Re: Electrified Cows

03/23/2009 3:13 PM

very nice answer you get my GA on that one.

__________________
pipewelder
Register to Reply
Anonymous Poster
#39

Re: Electrified Cows

03/24/2009 5:25 PM

Look at this document: http://www.hydroonenetworks.ca/en/customers/farm/strayvoltage/SVSolutionsGuideforElectrical_Contractors.pdf

havlokt@shaw.ca

Register to Reply Score 1 for Good Answer
Guru

Join Date: Feb 2006
Location: Piney Flats, Tennessee
Posts: 1740
Good Answers: 23
#40

Re: Electrified Cows

03/26/2009 6:03 AM

Was he system installed by KBR .

They have many problems espically in Iraq .

__________________
If you never do anything you never have problems.
Register to Reply
Register to Reply 40 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Age > IQ (4); Anonymous Poster (4); bhankiii (1); bhrescobar (1); CoronaCameraMan (4); dadw5boys (1); frankk (1); goalmaker (1); Goodho (1); Henrik14 (2); If_I_Only_Knew_Then (1); Jimh77 (1); Just an Engineer (1); Massey 726 (1); MrRoboto (1); North of 60 (5); noshorts (1); PetroPower (1); phoenix911 (1); pipewelder (1); StandardsGuy (1); Stilicho (1); Toomuchfun (2); Yusef1 (2)

Previous in Forum: R Square of Resistive Cloth   Next in Forum: MCCB Calculations

Advertisement