Electrical Fire Safety Flashcards

Which condition is most directly responsible for insulation failure that leads to arc faults in building wiring?

Answer: Damaged, aged, or compressed wiring insulation

Physical damage, aging, heat exposure, and compression degrade conductor insulation over time, allowing conductors to contact each other or nearby combustibles and arc, potentially starting fires.

What is the primary electrical fire hazard associated with aluminum branch circuit wiring in older residential buildings?

Answer: Aluminum oxidizes at connections, increasing resistance and generating dangerous heat

Aluminum forms an oxide layer at connections that significantly increases electrical resistance, generating heat at termination points that can ignite combustibles and cause fires.

When performing a fire safety inspection of an electrical room, which finding represents the most immediate fire risk?

Answer: Combustible materials stored inside the electrical room

Combustible materials stored in electrical rooms create an extreme fire hazard because electrical arcs, sparks, or overheated equipment can readily ignite them in an area difficult to reach for suppression.

Extension cords used as permanent wiring represent a fire hazard primarily because:

Answer: They are not designed for continuous use and may overheat over extended periods

Extension cords are designed for temporary, occasional use and lack the protection of permanent wiring; continuous use causes insulation degradation and overheating, which can ignite surrounding materials.

What does the term 'thermal runaway' refer to in the context of electrical fire safety?

Answer: A self-reinforcing cycle where increased temperature causes greater resistance, generating even more heat

Thermal runaway occurs when rising temperatures increase resistance, generating more heat, which further increases temperature in a dangerous positive feedback loop that can destroy equipment and cause fires.

A 'daisy-chained' power strip (one power strip plugged into another) is a fire hazard primarily because:

Answer: It can exceed the circuit's ampacity and the individual strips' ratings simultaneously

Daisy-chaining power strips allows connection of far more devices than the circuit or original strip was designed to support, leading to overloading, overheating, and potential fire.

Which NFPA standard specifically addresses electrical safety requirements in the workplace, including arc flash hazard analysis and personal protective equipment?

Answer: NFPA 70E

NFPA 70E, Standard for Electrical Safety in the Workplace, addresses arc flash, shock, and blast hazards, requiring employers to perform hazard analysis and provide appropriate PPE for electrical workers.