Where is the power network box mega fuse in a Ford Expedition?

There isn't a single, universally located "mega fuse" power network box in a Ford Expedition. The Expedition's electrical system uses a network of fuses and relays, spread across multiple locations. The main power distribution points are typically located in the underhood fuse box (often near the battery) and possibly an additional fuse box inside the passenger compartment.

To find the fuse or relay responsible for a specific circuit, you must consult your owner's manual. It will have a detailed fuse box diagram showing the location of each fuse and what circuit it protects. The manual is your best resource to identify the correct component and avoid damage.

Searching for a "mega fuse" implies you're looking for a very high amperage fuse protecting a major circuit. These high-amperage fuses might be found in the underhood fuse box, but they'll be clearly labeled in the diagram within the owner's manual. Do not attempt to work on electrical systems without understanding the diagrams and appropriate safety precautions.