Why where two horses electrocuted in Newbury?

ElectroSimon · Mar 2, 2011

I am wondering why these horses where electrocuted since the damaged cables where located underground would the fault current not have just returned to earth back to the star point of the transformer winding, why would it bother traveling up a horses leg?

Two horses have been killed by faulty underground cables at Newbury racecourse. The cables are believed to have been punctured during maintenance work.
Hundreds of spectators were watching the parade ring at Newbury when the horses suddenly reared up in pain. The horses are thought to have suffered catastrophic shocks from electricity cables that had been exposed by the work.
Two other horses were seen to wobble; bystanders who went to check up on the horses said they could feel electric shocks coming from their bodies.
The dead horses are thought to have been made vulnerable by their metal shoes. The two that died had steel shoes on and the two horses that were OK had aluminium plates on.
People who were standing nearby are likely to have been unaffected thanks to their leather or plastic soled shoes

Deleted member 9648 · Mar 2, 2011

Remember horses have 2 sets of feet with a stretch of ground between them.....a fault on the cable would have caused a voltage gradient across the ground in the vicinity of a fault....therefore there would have been a voltage difference between the horses front and back legs.Because of that a current could flow.

Deleted member 26818 · Mar 2, 2011

The current will always try to take the path of least resistance.
If going up the front legs along the body and down the back legs of a horse, offers a lower resistance than traveling 4 feet through the ground, then the horse will cop it.

IQ Electrical · Mar 2, 2011

wirepuller said:
Remember horses have 2 sets of feet with a stretch of ground between them.....a fault on the cable would have caused a voltage gradient across the ground in the vicinity of a fault....therefore there would have been a voltage difference between the horses front and back legs.Because of that a current could flow.

Yes, that's it, think of an earth electrode on a TT system, as earth leakage or fault current etc. is dissipated, the surrounding earth will be at a slightly increased potential.

This is why importance is attached to the siting of earth electrodes of supply transformers, small voltage gradients are lethal to 4-legged creatures, especially ones that have metallic shoes!

kamkam · Mar 2, 2011

"I am wondering why these horses where electrocuted since the damaged cables where located underground would the fault current not have just returned to earth back to the star point of the transformer winding, why would it bother traveling up a horses leg? "

The fault current was not big enough to blow the protection device for the cable.

peck06 · Mar 2, 2011

They'd have been fine if they were wearing rubber wellies rather than horse shoes....

Sorry had to get that in.

telectrix · Mar 2, 2011

it's because they hadn't paid up their annual niceic fees.

Golden_Boy · Mar 2, 2011

wirepuller said:
Remember horses have 2 sets of feet with a stretch of ground between them.....a fault on the cable would have caused a voltage gradient across the ground in the vicinity of a fault....therefore there would have been a voltage difference between the horses front and back legs.Because of that a current could flow.

Was the voltage being carried by the cable ever mentioned? If it was an 11kv distribution cable no wonder they where fried...

Adam W · Mar 2, 2011

peck06 said:
They'd have been fine if they were wearing rubber wellies rather than horse shoes....

Sorry had to get that in.

All it would take is a short length of 6mm to cross bond between the horses' front and back legs.

telectrix · Mar 2, 2011

they might run better with the 6mm hobbles. leastways faster than the last horse i backed. was in 1989, it's still running.

ElectroSimon · Mar 2, 2011

Yes that makes sense, i guess it would have saved the horses if they where "up stream " so to speak of the fault in the underground cable and the star point of the supply transformer and not of the path inbetween them as I have demonstrated in my nice little picture (I have time on my hands)

Golden_Boy · Mar 2, 2011

ElectroSimon said:
Yes that makes sense, i guess it would have saved the horses if they where "up stream " so to speak of the fault in the underground cable and the star point of the supply transformer and not of the path inbetween them as I have demonstrated in my nice little picture (I have time on my hands)
View attachment 3981

Especially if it WAS a HV distribution cable. The voltage gradient accross even a few feet of earth return would then be quite high.
If it where low voltage I doubt if the potential diffrence would be more that a volt or so?

ElectroSimon · Mar 3, 2011

So we can conclude that if they were wearing wellies or "up stream" from the cable or if they stood one one leg, they would have lived. I wonder if the offical report will include these findings?