Lorry contact video.

[BigClive]

Stuning video of a lorry that's made contact with a line.

http://www.break.com/index/boompower.html

[graybeard]

I hope no was hurt, but that was aqn awsome vid. I'm going to use it at a the next safety mtg.

[riverhog14]

someone else posted that a few months back, still fun to watch!

[BigClive]

Did the lorry driver get out. I shouldn;t think he'd be too comfortable sitting in the cab as the flames licked round it. Likewise any attempt to escape would have been dodgy given the amount of current passing to ground.

[Trampbag]

Now, can anyone tell me what possible difference grounding this unit would have made, except to add one more point to burn and widening the step gradient. How much greater would the problem would have been if all equipment had been bonded?

Someone should show this to the safety engineer who thinks grounding and bonding all equipment together is a good idea. Better still, the safety engineer should be put in the middle of the mess.

[BigClive]

Now, can anyone tell me what possible difference grounding this unit would have made, except to add one more point to burn and widening the step gradient. How much greater would the problem would have been if all equipment had been bonded?

I don't think it was associated with lineworks or even expecting that line to be there.

Bonding might have allowed enough current to flow to trip the circuit. Particularly if the vehicle was connected to a good earth point. I wonder what sort of potential difference was across the ground where the person filming was standing.

Amazing that it managed to blow the stabiliser in half and yet the crane rope itself remained intact.

[Trampbag]

Equipment making contact with high voltage systems will act exactly like what is seen on this video clip. Just because it is not a line truck doesn’t make the properties any different. If the equipment around the vehicle making contact were bonded together with several driven groundrods it would just make it a bigger, larger area energised and burning, and more dangerous to anyone working in the area. Bonding and grounding equipment is not a safety factor and will not save lives or serious injury.

I would like someone to explain, in technical jargon not a rhetorical sentimental explanative, why I’m wrong. I maintain that this relatively new technique, I never heard of it 20 years ago, of grounding and bonding equipment is dangerous and misleading to linecrews, and is just one more “safety technique” initiated by non-trades people, without consultation with tradesmen.

Simply put, I believe a lot of accidents are caused by just this type of misinformation interfering with the sound judgement of experienced personnel in this trade.

[riverhog14]

I think it was setting trusses on the house beside it, just a guess . But if the vehicle was not grounded, and the driver goes to step off with one foot on the crane and another on the ground, hes just another path to ground. If the vehicle was grounded, the circuit might have tripped. Also, when that driver goes to step off, he wont get as much current going through him. Maybe enough to save his life. Correct me if Im wrong, but electricity takes all paths ground, but travels most on the path of least resistance (the vehicle ground instead of the driver).

[Trampbag]

Let’s say for argument sake the live is138Kv. Within the first 8 seconds the pad was blown free of the rear right rigger thus making full metal contact with the ground. Several seconds later the front of the truck caught fire and started to arc, making a fine ground. All riggers were making great contact by this time, notice no tires were blowing nor even smoking meaning there are good paths to ground, better than the tires which usually blow quickly if unit is not well grounded.

Yes, electricity takes all paths to ground, and will travel most on one of least resistance more so, but at 138Kv humans don’t require a lot of amperage to severely mess them up.

I’ve seen a lot of these type videos and the aftermaths of accidents of this nature. Thank goodness I have never witnessed one first hand. In almost every instance if the operator had the balls to stay on the machine he survived, if not ultra serious injuries including death. Also the line did not trip until the power company operator or lineman tripped the line. I have seen sand turned to glass and ground rods or connections burn off while the equipment continued to burn.

Is there anyone out there who can explain, in technical terms, how a driven ground rod would have set up any more resistance thus changing the outcome of this situation?

[BigClive]

Is there anyone out there who can explain, in technical terms, how a driven ground rod would have set up any more resistance thus changing the outcome of this situation?

A better ground could have increased the current flow significantly enough to trip the protection. Although the stabilisers seemed to be providing some form of path to ground, the arcing at every joint and around the base would suggest that there was still a significant resistance there. I'd guess that the pads were preventing a good enough connection for significant current flow. Dry ground wouldn't have helped either.

Looking up and then keeping away from the lines would have worked even better. If the driver was OK then I bet he has a good look next time.