What must the emergency disconnecting means or operator simultaneously disconnect when serving gasoline or volatile flammable liquids?

The emergency disconnecting means or operator must simultaneously disconnect all conductors circuit supplying all station dispensers when serving gasoline or volatile flammable liquids. This requirement is in place to enhance safety during emergencies, ensuring that all electrical connections to dispensers that could become a source of ignition are immediately cut off.

By disconnecting all circuits, it minimizes the risk of electrical sparks or current that could ignite flammable vapors, which is particularly important in environments where combustible materials are present. This comprehensive disconnection addresses potential hazards associated with all equipment that dispenses fuel, thereby effectively reducing the risk of fire or explosion.

In contrast, focusing only on the main power source would leave local circuits connected, potentially creating hazards. Disconnecting just the local ventilation system or monitoring systems does not provide the necessary safety measures as those components can still interact with the fuel dispensing units and create risks. Hence, the overall approach of ensuring that all conductors connected to the dispensers are disconnected is the most prudent and safest measure for handling these volatile substances.