In what manner is an LP-gas motor/mobile fuel container installed in a vehicle's passenger or luggage compartment required to be filled?

The correct answer is that an LP-gas motor/mobile fuel container in a vehicle's passenger or luggage compartment must be filled by an external source remotely. This requirement is in place to enhance safety during the filling process. When filling LP-gas containers, the risks of leaks or potential hazards must be minimized, especially in confined spaces such as those found in a vehicle's passenger or luggage compartments.

Filling via an external source allows the operator to maintain a safe distance from the source of potential gas exposure. It also helps ensure proper ventilation and reduces the chance of ignition from any stray sparks or heat that may occur within the vehicle environment. Proper adherence to this practice is crucial for compliance with safety codes and regulations outlined in NFPA 58, which focus on minimizing the risks associated with LP-gas use and handling.

The other methods—manual filling, via an onboard system, and only during vehicle servicing—do not provide the same level of safety and risk mitigation. Manual filling may introduce too much risk of exposure to gas, while onboard systems could lead to complexities and potential hazards within the confined space. Only filling during vehicle servicing limits the accessibility and flexibility of fuel management. Therefore, utilizing an external source for filling these containers is the most responsible approach in terms