SOLUTION

The fuse rating is basically dependent on current-carrying to a particular connected load.

The order of the wring done for the consumer end connection is

1. From Secondary distribution transformers, power lines are sent to each pole present in the streets.
2. From the pole, each service main wire is connected to the energy meter of each house.
3. From the main meter, it is distributed to the main circuits of the building.
4. From the main circuit, it is then divided into sub-circuit connections.

The magnitude of current-carrying by the wries in the above process is given as

i_pole > i_meter  > i_{main circuit} > i_{sub circuit}

Hence pole caries are more current of different service mains of houses, pole fuse has the highest fuse rating. The current rating of pole fuse is ≈ 50 A.