Hope it dosen't happen!To anybody,

Please don't drive through any of our tunnels LOL

Thanks for the info RockApe, It made me a bit curious about it all to.day when i spotted a car that had side swiped a power pole.

Cheers Axle.

Rockape is spot on, just get out and keep your feet together and hop away, if you have to, otherwise stay in the car till you're told the wires are dead. The voltage gradient Rockape talks about is called step potential, and it falls away pretty quickly, so just stay or hop, and I wouldnt be too worried about touching metal stuff in the car.

Never heard of the truck tyres thing above or of animals dying from step potential on SWER lines, but certainly from touching low live wires with their big fat noses, inquisitive things that cows are.

Bonz,
for your info. If rubber tyred heavy machinery comes in contact with high voltage lines then it has to be left for 24 hours with an exclusion zone of 100 metres in case a tyre goes off. I had one go off (not due to high voltage) when I was in a shed about 60 metres away, that one landed a couple of large rocks on the roof. I will give you the drum it scared the living daylights out of me.

The cattle incident happened on a property south of McKinlay and I am told it was due to a bad earth at a transformer. Like you say cattle are inquisitive and have to all go over to see why their mates are taking a nap.

Have a good one.

Hmm interesting, I have seen heaps of trucks hit HV lines and no-one ever mentioned this tyre phenomenon. Thanx for the info.

I must have been a crook earth on the SWER line, must have been broken I reckon, but yes cows do have that wonder why theyre sleeping bent

All the best mate one learns all the time, after 30yrs mucking about with that stuff you'd reckon youd heard it all, now maybe I have.

Interesting posts, thanks all. Was curious to know the scientific reason for isolating the vehicles after ligtning strike or high voltage contact - plenty of info out there (PYROLYSIS).

This extract from the QLD NRME Dept:
"Tyres on trucks, cranes and other heavy vehicles may catch fire under a range of circumstances, with the obvious potential for the tyres to then explode. A lesser-known danger arises when the combustion takes place inside the tyre, with no external signs. Whenever excess heat is developed in or applied to a tyre, it can initiate a process within the tyre known as pyrolysis - the decomposition of a substance by heat.
This can cause a build-up of flammable gases and pressure within the tyre, which may ultimately rupture or explode. Enormous amounts of energy can be released by a tyre explosion, often leading to significant equipment damage, serious injuries or fatalities.
Pyrolysis related explosions are unpredictable, and have occurred immediately or up to 24 hours after initiation. An explosion can occur where no fire is visible and the danger area can be up to 300 metres from the tyre.
Tyre pyrolysis has occurred from welding on wheel rims, oxyheating wheel nuts, overheating brakes and wheel motor fires. It has also resulted from electrical arcing and current flow when rubber tyred vehicles have been involved in high voltage electrical incidents. Vehicles affected have included rubber tyred cranes and tip trucks, often as a result of collision with overhead supply lines. However, any rubber tyred vehicle involved in an incident where an electrical fault results in discharges or arcing around or through the tyres should be considered as a potential hazard."