If you're looking for a way to quickly stop fuel flow in an emergency (e.g., a fire), you'd need to locate the fuel pump relay or fuse. This location varies significantly depending on the year and model of your Ford Transit. You'll need to consult your owner's manual or a wiring diagram specific to your vehicle. Pulling the fuel pump relay or fuse will cut the power to the fuel pump, preventing fuel flow.
Caution: Disconnecting the fuel pump in this way is not intended as a normal engine shutoff method and should only be used in emergencies. Incorrectly handling electrical components can be dangerous. If you are unsure about any of these procedures, consult a qualified mechanic.