fuse melting

[mario f]

Greetings to all,
Please help me figure out why my fuse is melting ?
Fridge power, fused at 15a fuses do not blow, just start to melt at output side of fuse (little blue plug in type).
If it is over current fuse would blow no?
Never had this issue in 2 years with this system, properly sized wire, checked all connections etc.
Any ideas?

Thank you

Mario

[Sailmonkey]

You've got corrosion on the fuse holder causing a voltage drop....heat....clean or replace the fuse holder and carry on.