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Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that bit about cyanide? Ha! When your sofa catches on fire it releases cyanide. That's why we wear positive pressure SCBAs. [0] We typically cut battery cables on conventional cars to lessen the danger of an airbag exploding in our face during a rescue.

FireBeyond 6y ago
> Our department has trained on hybrids (don't cut the big orange cable!) Keep training up to date. Hybrid HV wiring has a conductive sheath around the actual wiring, separated by non conductive layers. The purpose of this is that when your tool cuts such wiring, it shorts the sheath first and trips a breaker, so that you should be able to cut. There's a group near here (WA state) that does demos including "throwing" (dropping) battery packs into wading pools while still supplying power, and cutting HV cables on running hybrids to demonstrate this. But then again, there's near zero reason to do so. Stabilize the vehicle, kill the 12V. Our general go-to? Put the hazard lights on. If you stop the hazards, the vehicle is "generally electrically safe". Biggest risk that isn't often talked about? HID headlights. Picture being up against the frame of the car. Regular headlights, bulb broken, possibly? Pretty low risk. Broken headlight, and behind it is a high voltage arc? That's a very real electrocution hazard.
- dreamcompiler 6y ago
  Holy crap! I learned a lot from this; gonna research and take it to the crew. Thanks and stay safe!
  - FireBeyond 6y ago
    You too. For sure, I remember when I got an 07 Prius, and we started talking about this stuff, and there was a lot of urban legends and myths. That being said, while electricity obeys the laws of physics, MVA/MVCs throws a wild card into the equation. I err on the side of caution... "Why am I cutting this cable if the vehicle is powered down and stabilized?"
    - dreamcompiler 6y ago
      Yup. It's easy to pull out the trusty center punch and shatter the side glass when you're amped up on adrenaline trying to get to the patient, but as my Chief says: "First try the door handle." That usually works.
      - retSava 6y ago
        Makes me think of Terminator 2, when JC teaches T to flip the sunshade for keys instead of mashing the ignition key hole. That in turn makes me think about that - was it common during those days to do that, store the keys there? Perhaps for shared service vehicles?
        XorNot 6y ago
        This is a Hollywood thing where writers in Hollywood don't know how the normal world works: storing the keys under the sunvisor is a thing that is done with studio vehicles in studio lots because the car changes hands a lot and so keeping the keys in it just makes sense. It might've been common in a few American cities Hollywood-adjacent post-WW2 as well, but the accepted explanation is essentially that it's Hollywood being Hollywood - probably that it's a rite of passage as a junior team member to be unable to find the keys and then have someone show you they're in the "obvious" place. Though I suspect at this point it's a writing shortcut more then anything else: we all know it's a movie, in movie's this happens, and in the plot in that moment you don't want to deal with "can these characters start this car".
        mgkimsal 6y ago
- deleted 6y ago
  [deleted]
- throwaway0a5e 6y ago
  >Pretty low risk. Broken headlight, and behind it is a high voltage arc? That's a very real electrocution hazard. There's not enough amps available there to do anything serious.
  - jws 6y ago
    80-90V to keep it running are above the "low voltage" guidelines and their ~500mA is enough to kill. Presumably the driver circuit would notice that no current is flowing from a ruined bulb, try the sparker a few times to restart the arc, then give up and turn off the 90V drive. But it might be cheaper to build…
sandworm101 6y ago
Be more worried about the carbon fiber. In many ways it is like dealing with flamable aspestos.
imglorp 6y ago
Unscheduled airbag deployment is a terrifying concept if you're trying to lean in to access a person. Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars? It wouldn't have to be a big red sign but it could be a standard.
- HPsquared 6y ago
  Probably budget, and ejection seats are a bit more dramatic than airbags.
- Reason077 6y ago
  > "Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars?" Not sure if it's standard on all EVs, but cutting the first responder loop on a Tesla will disarm the airbags & SRS, in addition to disconnecting the high voltage system. Source: Tesla first responder guide: https://www.nfpa.org/-/media/Files/Training/AFV/Emergency-Response-Guides/Tesla/Tesla-Model-3-EV-2017-2018-ERG.ashx https://www.nfpa.org/-/media/Files/Training/AFV/Emergency-Re...
  - imglorp 6y ago
    > first responder guide This is exactly what I'm complaining about. Every car is different. Volunteers have so many trainings to take, it's unreasonable to ask them to take a whole training for EVERY MODEL CAR on the road. There should be a simple, standard, HV and pyro cutoff control, standard on ALL cars, that can be actuated without a hydraulic shear. Put it in the wheel well or behind a gascap-like door. Imagine you are a civilian or first responder and want to help people out of a car and you don't have a hydraulic shear or hundreds of hours of model-specific training? This is an everyday usecase.
    - gregd 6y ago
      Training on fire suppression and extrication techniques for cars doesn't take THAT much training. Most techniques would be standard across the board, with a few exceptions for electric vehicles. Additionally, never underestimate the hours of training that most firefighters go through anyway and get this, they live for that stuff.
gregd 6y ago
Former firefighter here also. We also used to have to worry about the compressed gas cylinders on bumpers.
- jacobush 6y ago
  Wait what?
ZeteticElench 6y ago
I am worried about the possibility of a chain reaction of electric cars when they become common enough. Imagine a parking garage full of thousands of electric cars and one spontaneously starts of fire due to a battery defect and then the ones next to it catch fire and then the ones next to those and then eventually you have a LOT of cars on fire that sprinklers cannot put out.
m463 6y ago
Do you cut the cables twice? I read the electric vehicle procedure and they say to cut the battery cutoff cable twice. I thought that was interesting - I guess it makes sense you don't want to release that cable so the two ends fall back together and create a welding rig.

FireBeyond 6y ago

> Our department has trained on hybrids (don't cut the big orange cable!) Keep training up to date. Hybrid HV wiring has a conductive sheath around the actual wiring, separated by non conductive layers. The purpose of this is that when your tool cuts such wiring, it shorts the sheath first and trips a breaker, so that you should be able to cut. There's a group near here (WA state) that does demos including "throwing" (dropping) battery packs into wading pools while still supplying power, and cutting HV cables on running hybrids to demonstrate this. But then again, there's near zero reason to do so. Stabilize the vehicle, kill the 12V. Our general go-to? Put the hazard lights on. If you stop the hazards, the vehicle is "generally electrically safe". Biggest risk that isn't often talked about? HID headlights. Picture being up against the frame of the car. Regular headlights, bulb broken, possibly? Pretty low risk. Broken headlight, and behind it is a high voltage arc? That's a very real electrocution hazard.

dreamcompiler 6y ago
Holy crap! I learned a lot from this; gonna research and take it to the crew. Thanks and stay safe!
- FireBeyond 6y ago
  You too. For sure, I remember when I got an 07 Prius, and we started talking about this stuff, and there was a lot of urban legends and myths. That being said, while electricity obeys the laws of physics, MVA/MVCs throws a wild card into the equation. I err on the side of caution... "Why am I cutting this cable if the vehicle is powered down and stabilized?"
  - dreamcompiler 6y ago
    Yup. It's easy to pull out the trusty center punch and shatter the side glass when you're amped up on adrenaline trying to get to the patient, but as my Chief says: "First try the door handle." That usually works.
    - retSava 6y ago
      Makes me think of Terminator 2, when JC teaches T to flip the sunshade for keys instead of mashing the ignition key hole. That in turn makes me think about that - was it common during those days to do that, store the keys there? Perhaps for shared service vehicles?
      - XorNot 6y ago
        This is a Hollywood thing where writers in Hollywood don't know how the normal world works: storing the keys under the sunvisor is a thing that is done with studio vehicles in studio lots because the car changes hands a lot and so keeping the keys in it just makes sense. It might've been common in a few American cities Hollywood-adjacent post-WW2 as well, but the accepted explanation is essentially that it's Hollywood being Hollywood - probably that it's a rite of passage as a junior team member to be unable to find the keys and then have someone show you they're in the "obvious" place. Though I suspect at this point it's a writing shortcut more then anything else: we all know it's a movie, in movie's this happens, and in the plot in that moment you don't want to deal with "can these characters start this car".
        mgkimsal 6y ago
deleted 6y ago
[deleted]
throwaway0a5e 6y ago
>Pretty low risk. Broken headlight, and behind it is a high voltage arc? That's a very real electrocution hazard. There's not enough amps available there to do anything serious.
- jws 6y ago
  80-90V to keep it running are above the "low voltage" guidelines and their ~500mA is enough to kill. Presumably the driver circuit would notice that no current is flowing from a ruined bulb, try the sparker a few times to restart the arc, then give up and turn off the 90V drive. But it might be cheaper to build…

sandworm101 6y ago

Be more worried about the carbon fiber. In many ways it is like dealing with flamable aspestos.

imglorp 6y ago

Unscheduled airbag deployment is a terrifying concept if you're trying to lean in to access a person. Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars? It wouldn't have to be a big red sign but it could be a standard.

HPsquared 6y ago
Probably budget, and ejection seats are a bit more dramatic than airbags.
Reason077 6y ago
> "Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars?" Not sure if it's standard on all EVs, but cutting the first responder loop on a Tesla will disarm the airbags & SRS, in addition to disconnecting the high voltage system. Source: Tesla first responder guide: https://www.nfpa.org/-/media/Files/Training/AFV/Emergency-Response-Guides/Tesla/Tesla-Model-3-EV-2017-2018-ERG.ashx https://www.nfpa.org/-/media/Files/Training/AFV/Emergency-Re...
- imglorp 6y ago
  > first responder guide This is exactly what I'm complaining about. Every car is different. Volunteers have so many trainings to take, it's unreasonable to ask them to take a whole training for EVERY MODEL CAR on the road. There should be a simple, standard, HV and pyro cutoff control, standard on ALL cars, that can be actuated without a hydraulic shear. Put it in the wheel well or behind a gascap-like door. Imagine you are a civilian or first responder and want to help people out of a car and you don't have a hydraulic shear or hundreds of hours of model-specific training? This is an everyday usecase.
  - gregd 6y ago
    Training on fire suppression and extrication techniques for cars doesn't take THAT much training. Most techniques would be standard across the board, with a few exceptions for electric vehicles. Additionally, never underestimate the hours of training that most firefighters go through anyway and get this, they live for that stuff.

gregd 6y ago

Former firefighter here also. We also used to have to worry about the compressed gas cylinders on bumpers.

jacobush 6y ago
Wait what?

ZeteticElench 6y ago

I am worried about the possibility of a chain reaction of electric cars when they become common enough. Imagine a parking garage full of thousands of electric cars and one spontaneously starts of fire due to a battery defect and then the ones next to it catch fire and then the ones next to those and then eventually you have a LOT of cars on fire that sprinklers cannot put out.

m463 6y ago

Do you cut the cables twice? I read the electric vehicle procedure and they say to cut the battery cutoff cable twice. I thought that was interesting - I guess it makes sense you don't want to release that cable so the two ends fall back together and create a welding rig.