Horse die from electric shock

[mikep]

Four legged animals are more likely to die in this situation due to the path of electricity is always across their chest via the front legs or front to back legs, with us it would be up one leg and down another unless we got on all fours, a live cable in the ground would be radiating out in all directions and a path through anything within the vacinity of the live conductor would be taken ( eg a horse ) to get back to a point of earth on the main supply (potential difference)

This supply could be just a "TT" supply and has been damaged exposing the line conductor in the ground by mechanical spikes for aerating the grass or something like this, some of these machines core to 600mm easily to assist drainage of the ground!!

This is what I think what happened, any other views.

Regards all, Mike

 

[Manator]

The latest update is that a punctured cable has been found, most probably the cause. Still has to be confirmed though at this stage.

 

[Andy™]

HV or LV?

 

[Manator]

Not sure on the details, looks like more investigations to be done, I would suspect LV.

 

[sellers]

[quote name='Andy

 

[Sidewinder]

:innocent

 

[SLIPSHOD & SLAPDASH]

It must have been a great shock to the people there.

Obviously not, only to the horses

 

[gordy71]

What does everybody think about the horses that died at newbury from electric shocks? Apparently there was a damaged cable buried deep in the ground that electrocuted the two horses. The footage can be found on youtube. I thought that if the cables are buried in the ground the current would dissapate into the earth as this is where any current wants to go? Also the horses carry on moving after the 'shock', but i thought if you had a big enough shock to die you would collapse straight away? :C

 

[ProDave]

It's something to do with being quadrupeds rather than bipeds. That means their legs are further apart than us bipeds.

So any current flowing through the ground will, over the larger span of their legs, build up a larger PD than our two legs closer together.

Plus we wear mainly plastic shoes that will give some insulation, and they wear nice metal shoes.

This also happens with lightening stikes, cattle and horses can be electrocuted by the resultant current flowing through the ground in close proximity to the strike, while us bipeds are unaffected.

You have to remember "ground" is not all one equipotential mass. It is earth, which will have a resistance. Any fault current would be trying to make its way from where the fault is, to where the source was earthed, thus flowing through the ground.

 

[kme]

See the other thread, started on Saturday

Mods - maybe this could be "tacked on" to the other thread - seems daft to have 2 of em going at once......

 

[gordy71]

ok thanks dave that makes sense, so any current flowing up one leg will flow through their heart if their is PD. Do you think this is a cover up or genuine accident? Just sounds a bit random to me. Yes my missus is a farrier so she told me about it, but wasnt sure how to explain it when she showed me!

---------- Post Auto-Merged at 19:22 ---------- Previous post was made at 19:21 ----------

Sorry kme didnt realise.

 

[Doc Hudson]

Two threads merged.

Doc H.

 

[kerching]

[quote=Apache;187380

I knew of a farmer who had 2 cows die when an electric milk pump in the milking parlour failed and 2 cows dropped dead in the parlour before the RCD tripped. They were fun to drag out before the farmer could get the pump mended and milk.

Wasn't near Halifax was it?

 

[Apache]

It's something to do with being quadrupeds rather than bipeds. That means their legs are further apart than us bipeds.So any current flowing through the ground will, over the larger span of their legs, build up a larger PD than our two legs closer together.

I don't believe you! The main issue is how the shock occurs and the ability of that to carry the current through the body. Horses have metal shoes. Cows and sheep often standing in some slurry which is wet. They are frequently on grass which is often wet, especially in a thunder storm. Often animals explore with their wet mouth.

In a person usually they get a shock via the hand which earths via the legs - going across the chest. People usually have insulating footwear.

This is why we have special regs for bathrooms - bare wet feet.

Kerching - cows died not near Halifax. This does happen every now and gain.

 

[Sidewinder]

Patch,

What do you reckon the normal step spread of a race horse would be, 2, 2.5m, more, less?

At this point what would the closest legs be at?

30mA can kill a human, it is said that it is less for a horse, there is an IEC document, but I can't find my copy now.

Lets say for ease 50mA.

Work with me on this, all of you please?

To get 50mA across the legs at max reach, or min reach this would need a PD of?

Damp ground resistance could be?

We obviously don't know the resistance of the horse, but we can model this on a voltage gradient in the ground, think about earth rods and spheres of influence etc.

 

[steptoe]

I don't believe you! The main issue is how the shock occurs and the ability of that to carry the current through the body. Horses have metal shoes. Cows and sheep often standing in some slurry which is wet. They are frequently on grass which is often wet, especially in a thunder storm. Often animals explore with their wet mouth.In a person usually they get a shock via the hand which earths via the legs - going across the chest. People usually have insulating footwear.

This is why we have special regs for bathrooms - bare wet feet.

Kerching - cows died not near Halifax. This does happen every now and gain.

him with a foot (so to speak ) in both camps has spoken.

:worship

 

[Apache]

What do you reckon the normal step spread of a race horse would be, 2, 2.5m, more, less?At this point what would the closest legs be at?

2 metres max, an average height man couldn't lay between them, more like 1.5metres assuming standing square. A horse can stand with almost no distance between front and back feet.

Do we not need a resistance before we can consider a PD?

 

[SPECIAL LOCATION]

I don't believe you! The main issue is how the shock occurs and the ability of that to carry the current through the body. Horses have metal shoes. Cows and sheep often standing in some slurry which is wet. They are frequently on grass which is often wet, especially in a thunder storm. Often animals explore with their wet mouth.In a person usually they get a shock via the hand which earths via the legs - going across the chest. People usually have insulating footwear.

This is why we have special regs for bathrooms - bare wet feet.

Perching - cows died not near Halifax. This does happen every now and gain.

Pro dave's statement is a factually correct statement Apache.

The Electrcal Safety Councils technical manual topic E5-4 discusses some aspects, here is a small extract:-

(in this context they are discussing the ground area around a vertical earth rod, during the instant of an earth fault where the rods potential would be rising toward 230v..)

3. Risk of electric shockDepending on its value (volts per meter) and duration, the potential gradient likely to exist over the surface of the ground within the resistance area of an earth electrode under earth fault conditions may constitute a danger. Persons and livestock in contact with two points within the resistance area sufficiently far apart, may be subjected to a difference of potential that may result in an electric shock. Large four-legged animals such as cattle can be particularly vulnerable.

The typical nature of the potential gradient at or near the surface of the ground around a single vertical rod-type earth electrode can be seen from the graph in Fig 2. The slope of the curve, i.e. the change of the ground surface potential with distance, is the potential gradient. This decreases as the distance from the earth electrode increases.

I will describe the concept in sort of lay mans non-technical terms:

If you imagine the top of the buried earth rod is at 230v, and the earth and soil immediately around it is also at 230v

then say 1m away the soil is back at Ov..

If you got both your bare feet on the 230v you get no shock..

(bit like birds on the HV power pylons!)

But if you got one bare foot over the 230v & one bar foot over the 0v

you got 230v up your legs & across your "mans important bits"!

If you happen to be a four legged beastie this could also be across the heart!

 

[Sidewinder]

Patch,

See ^

Ok so we have less than 2m.

Now we need a fault current, earth resistance, and resistance of a horse perhaps.

Where next.

Let's stick to easy numbers though eh for the first run through the model?

 

[Apache]

Where do I attach my multimeter to the horse?

I know what you are saying, but I still think that if you put them in wellies it wouldn't be an issue, and that the metal shoes, wet grass is much more of a factor. A cow has a big 150-200litre fermentation vat [rumen] that is basically a load of salty water that I have no doubt helps the conductivity of a cow over a human or even a horse.