FST Electrical Fire Safety 3

Question 1

Class C fires involve which type of material, and what extinguishing agent must never be used on them?

Accepted Answer

Energized electrical equipment; water-based agents

Answer

Flammable liquids; dry chemical agents

Answer

Ordinary combustibles; CO2 agents

Answer

Combustible metals; foam-based agents

Question 2

When inspecting fire-rated wall assemblies for electrical fire hazards, which finding requires immediate correction?

Accepted Answer

Unsealed conduit or cable penetrations allowing fire and smoke passage through the barrier

Answer

Conduit runs that are not labeled at both ends of a fire-rated wall

Answer

Electrical cables routed in conduit rather than installed as direct burial

Answer

Conduit bends that appear to exceed 45 degrees near the wall penetration

Question 3

What is the primary purpose of a Listed overcurrent protection device (OCPD) from a fire safety perspective?

Accepted Answer

To interrupt current flow before conductors overheat to the point of igniting insulation or surrounding materials

Answer

To regulate voltage within acceptable ranges for all connected equipment

Answer

To detect ground faults and arc conditions before a conventional circuit breaker responds

Answer

To provide transient surge protection for sensitive electronic equipment

Question 4

In which occupancy type has AFCI circuit breaker protection been most broadly required by the National Electrical Code since 1999?

Accepted Answer

Dwelling units (residential occupancies)

Answer

Business and mercantile occupancies

Answer

Industrial manufacturing facilities

Answer

Healthcare and ambulatory care facilities

Question 5

During an electrical fire safety inspection, a technician finds flexible metal conduit (FMC) used for a concealed run exceeding 6 feet. This is a concern because:

Accepted Answer

Lengthy FMC in concealed locations may not provide reliable grounding or adequate mechanical protection

Answer

FMC is prohibited in all concealed locations regardless of the length of the run

Answer

Flexible conduit is incompatible with copper conductors in branch circuit applications

Answer

FMC connections are not approved for use with standard metal junction boxes

Question 6

Which electrical installation practice most effectively reduces the risk of arcing fires at wiring connection points?

Accepted Answer

Torque tightening all connections to manufacturer specifications using a calibrated torque wrench or driver

Answer

Applying multiple layers of electrical tape over all wire splices and connections

Answer

Installing wire of a larger gauge than required for the intended circuit ampacity

Answer

Replacing copper branch circuit wiring with aluminum to reduce oxidation resistance

Question 7

What electrical hazard do lithium-ion batteries primarily introduce that is of concern to Fire Safety Technicians inspecting modern facilities?

Accepted Answer

Thermal runaway leading to self-sustaining fires that are difficult to extinguish with conventional agents

Answer

High voltage arcing when battery terminals are short-circuited during inspection

Answer

Emission of carbon monoxide gas during normal charging and discharging cycles

Answer

Ground fault currents that can activate GFCI devices and cause nuisance tripping