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Difficulty: MediumFires and Fire Extinguisher Use

While parked at a roadside staging area, a commercial driver discovers smoke and sparks originating from exposed electrical wiring beneath the cab dashboard. Which action represents the safest and most effective procedure for suppressing this fire?

  1. A
    Pour water directly behind the dashboard panel to rapidly cool the heated electrical components.
  2. Turn off the vehicle electrical power and discharge a B:C or A:B:C dry chemical extinguisher at the base of the fire.Answer
  3. C
    Switch the cab ventilation blower to maximum speed to force smoke and heat out through open windows.
  4. D
    Discharge a Class A water extinguisher directly into the uppermost tips of the visible flames.

Answer

Turn off the vehicle electrical power and discharge a B:C or A:B:C dry chemical extinguisher at the base of the fire.
For an in-cab electrical fire, the driver must immediately turn off the vehicle's electrical power to de-energize the circuit and use a B:C or multi-purpose A:B:C dry chemical extinguisher aimed at the base of the fire. Dry chemical extinguishers are non-conductive and coat the burning material to extinguish the source.

Step-by-Step Solution

1
Identify the fire classification and primary ignition source.
The fire involves energized electrical wiring beneath the dashboard, classifying it as a Class C electrical fire.
Recognizing the fire class determines the proper extinguishing agent and safety precautions.
2
Eliminate the electrical energy source.
Turn off the ignition switch and disconnect electrical power if accessible.
De-energizing the circuit stops the heat-producing electrical short and reduces electrical shock risk.
3
Select the correct extinguisher and apply the proper suppression technique.
Use a B:C or multi-purpose A:B:C dry chemical fire extinguisher, aiming the discharge directly at the base of the fire rather than the flames.
Dry chemical agents are non-conductive and smother the fire at its physical fuel source.

Key Concept

Class C electrical fire suppression requires shutting off power, using non-conductive dry chemical extinguishing agents, and aiming directly at the base of the fire.
Estimated Time:1m 0s
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Topics

Fires and Fire Extinguisher Use

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