brandeeno
Member
Several have come to the conclusion that the battery pack did not burn for given reasons.... if so, then how do you explain the melted body which would require a lot of energy to melt?
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green1
Active Member
This is exactly the question I was pondering as well. My conclusion is that the car had flammable cargo on board.
Neither step potential nor touch potential is worsened by stepping on conductive water on top of the conductive ground. Step potential is also completely irrelevant at such low voltage, and I would think that the fire fighters have enough sense to not go up and lean against the car or supercharger. If they don't, they could be electrocuted with or without the water.
green1
Active Member
You obviously didn't look up step potential. it is exactly about a charge flowing on a grounded surface.
As for the voltage, they have no idea what the voltage is, they know a car attached to a high voltage station is on fire, they don't know why, for all they know something shorted or grounded across the transformer and they have several kv in there.
Vince Cobelo
Member
Here is why you can use water on a electrical fire... Peeing On An Electric Fence - What Happens? - YouTube
And another example... MythBusters- Peeing on Third Rail | MiniMyth - YouTube
And another example... MythBusters- Peeing on Third Rail | MiniMyth - YouTube
Yes, and the surface in question is grounded with or without water. Dry asphalt conducts electricity, wet asphalt conducts electricity.
It's a pretty good hint that the transformer is completely unharmed. With some more training they would be more prepared and know where they could expect what voltages in which circumstances.
stopcrazypp
Well-Known Member
While if they extinguished the fire, it would help investigation drastically (and reduce bad press of having the whole car burn down), I think they chose the safe route by letting it burned down. We know more than a vast majority of people about the supercharger cabinet voltages, but at the time they wouldn't have known if the voltage was safe to use water on.
In the US, there are water fog nozzles and separation distance guidelines that allow firefighters to fight electrical fires with water even when they are at the tens of kV levels. Not sure if it is there in Norway. But choosing to let it burn out is a safe route to take when the fire is isolated.
In the US, there are water fog nozzles and separation distance guidelines that allow firefighters to fight electrical fires with water even when they are at the tens of kV levels. Not sure if it is there in Norway. But choosing to let it burn out is a safe route to take when the fire is isolated.
Multiple posts regarding the Norwegian Tesla Fire moved here: A Model S just caught fire while supercharging in Norway (link in Norwegian))
Hear hear!
Best possible outcome = 1 totaled Model S and zero casualties.
Actual result = 1 totaled Model S and zero casualties.
For all those saying yes but water puts it out. I agree, but as soon as a car has a grounding circuit making the body electrically at the same potential as true earth (the water the fire fighters are standing in). i.e. it's plugged in, airing on the side of caution is 100% the best approach. The simple fact the car is plugged in changes things, and is not detailed in the Emergency Responders Guide.
There was brief mention of broken neutral in an earlier post, and this is a genuine hazard, albeit unlikely. (Where the car body becomes live relative to earth, maybe even at mains AC voltage)
There could well be a common grounding scenario where DC ground is tied into the AC protective earth. (common in many switch mode AC to DC designs) TBH I don't know if the Tesla chargers work that way or not, and without detailed charger schematics I couldn't say one way or the other. To be brutally honest nor could the Norwegian Firecrew....
Until Tesla put in place detailed guidance for first responders attending a vehicle fire WHILST IT IS PLUGGED IN, then I honestly don't think the fire fighters put a foot wrong.
Would it have been nice if the photo was less dramatic. Sure.
Will it be better in the future if this scenario is clearly described. Sure.
Could the outcome in terms of the fire crews stated objectives be better: Nope.
Please let's stop the witch hunt guys, these people are only doing their best to keep us all safe!!!
Aluminium (which is used in the Model S) has a much lower melting point than steel (which is used in most other cars). 660C vs approx 1350C. Which explains why the result of this fire look much more extreme than maybe it is.
This might just be how any Model S will look after a fire in the interior of the car.
brandeeno
Member
I was skeptical that things inside the car could burn hot enough to melt even aluminum, and found a great series of progressive pictures of a Ford F-150 (aluminum body) from the start of the fire all the way to end where its just rubble. There is even a picture with "electrical" looking sparks on this ICE car. Ford F-Series Super Duty prototype reduced to smoldering mess of aluminum and steel [UPDATE]
EarlyAdopter
Active Member
No, it doesn't. Just look at the results of the fires in 2013 when fire fighters dowsed the car with water. Far more intact.
We need to stop perpetuating this myth that "battery electric car fires can't be put out with water." This is utter nonsense and could cost someone their life some day.
I've melted aluminium in backyard bonfires. It really isn't hard 
To melt steel requires BBQ coals and a leaf blower... don't ask how I know :redface:
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Again show me the documentation that says this is Tesla approved procedure WHILST THE CAR IS PLUGGED IN.
We are all learning, and eventualities not envisaged will come up. It's the nature of early product cycle.
Devils advocate: If your Model S (heaven forbid) was on charge and caught fire, would you personally just spray it with water whilst the power was still on?
I feel fairly educated on this, I don't think EVs are any more dangerous than ICEs, but I wouldn't.
I'd get my family clear and just let it burn.
To melt steel requires BBQ coals and a leaf blower... don't ask how I know :redface:
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Again show me the documentation that says this is Tesla approved procedure WHILST THE CAR IS PLUGGED IN.
We are all learning, and eventualities not envisaged will come up. It's the nature of early product cycle.
Devils advocate: If your Model S (heaven forbid) was on charge and caught fire, would you personally just spray it with water whilst the power was still on?
I feel fairly educated on this, I don't think EVs are any more dangerous than ICEs, but I wouldn't.
I'd get my family clear and just let it burn.
+100
Elon once said, you don't see terrorists making bombs out of batteries. Or something to that affect.
EarlyAdopter
Active Member
From https://www.teslamotors.com/sites/default/files/downloads/en_EU/model_s_2014_emergency_response_guide.pdf?1505
Tesla says you should _always_ assume the car is energized at high voltage (420V max pack voltage) when fire fighting, plugged in or not, yet recommends dowsing it with high volumes of water. The warnings are against touching the car, not hosing it down. Fresh water is a poor conductor of electricity, and last time I checked firefighters wear rubber boots.
Indeed, and my experience of anything health and safety regulated is unless you can pass the buck up the line to some one more qualified is you take the path of caution when human life is involved.
Some laws are of nature, but some laws (human made ones) seek blame....
