EVITP First Responder and Emergency Safety for EVs and Charging Sites — Questions and Answers
Question 1: Which color identifies high-voltage cabling in electric vehicles?
- Red
- Blue
- Orange (Correct answer)
- Green
Correct answer: Orange
Under SAE J1673 and industry practice, EV high-voltage cables are orange so technicians and responders can spot them.
Question 2: What is thermal runaway in a lithium-ion EV battery?
- A slow loss of charge in cold weather
- A self-sustaining chain reaction where cell heating causes more heating, which can lead to fire or explosion (Correct answer)
- The battery management system shutting off charging
- A charger overheating from a loose terminal
Correct answer: A self-sustaining chain reaction where cell heating causes more heating, which can lead to fire or explosion
Thermal runaway happens when a damaged or failing cell releases heat that spreads to nearby cells, producing an escalating reaction that is hard to stop.
Question 3: Why is a battery that has been in an EV fire a hazard even after the flames are out?
- It can no longer hold any charge
- Stranded energy and damaged cells can re-ignite hours or days later (Correct answer)
- It becomes non-conductive
- It automatically discharges to zero
Correct answer: Stranded energy and damaged cells can re-ignite hours or days later
Damaged cells keep stored energy and can go into delayed thermal runaway. Vehicles are usually monitored or isolated after a battery fire.
Question 4: A responder approaches a crashed EV that is completely silent. What should they assume?
- The vehicle is definitely off
- The vehicle may still be powered on ('ready' mode) and could move, so it must be immobilized and powered down (Correct answer)
- The high-voltage system is always de-energized after a crash
- The 12 V battery has no role in shutdown
Correct answer: The vehicle may still be powered on ('ready' mode) and could move, so it must be immobilized and powered down
EVs make no engine noise, so silence doesn't mean the vehicle is off. Responders should chock the wheels, put it in park, and power it down following the manufacturer's emergency response guide.
Question 5: Under NEC 625.43, what disconnecting means is required for EVSE rated over 60 A or over 150 V to ground?
- None; the vehicle provides disconnection
- A disconnecting means in a readily accessible location that can be locked in the open position (Correct answer)
- A disconnect only inside the utility's vault
- A cord-and-plug connection only
Correct answer: A disconnecting means in a readily accessible location that can be locked in the open position
NEC 625.43 requires a readily accessible, lockable-open disconnect for larger EVSE, so the equipment can be de-energized safely in an emergency or during service.
Question 6: Compared with a gasoline vehicle fire, what is generally true about fighting a lithium-ion EV battery fire?
- It needs much less water
- It can need much larger volumes of water applied over a longer time to cool the battery pack (Correct answer)
- A small dry-chemical extinguisher always puts it out
- Water must never be used
Correct answer: It can need much larger volumes of water applied over a longer time to cool the battery pack
Fire service guidance (for example, from NFPA and manufacturers' emergency response guides) says battery fires often need sustained cooling with large volumes of water to stop thermal runaway.
