What can be the reason for a three phase fused socket to always blow the same fuse?
To be sure if the problem comes from the load, I should shift the phases of wires. That is, if existing wiring connection is Fuse1-Wire1,Fuse2-Wire2, Fuse3-Wire3, then change to Fuse1-Wire2,Fuse2-Wire3, Fuse3-Wire1. Rotation will keep the same, and check again. If same fuse is blowing, could be an issue in fuse holder (bad contact is heating the fuse). If the fuse blown is another one, the fault is in the load, may be a ground fault or unbalanced current.