Electric fan control question

[Whaler]

Hi all
Sorting out my car. Now has 345 miles on it and noticed it getting hot yesterday 100-105 C
So I was close to home and whipped into the garage to notice the electric fan not on.

Troubleshooting began

1) Overide switch had no effect, but isolated switch was good with a meter on ohms
2) Fan worked with 12 volts supplied to it directly sourced into the inline fuse
3) 30 amp fan relay worked well and also had the 12 volts supply to it.
4) 30 amp- inline fuse to fan motor was intact (load)

So after an hour, I went to the last and most obvious, the fan control fuse in my wiring harnesses fuse block. Sure as heck the 20 amp fuse in the block was open. Replaced it and fan worked both in auto temp control and manual overide.

So here's my question, the fan motor (load) has an inline 30 amp fuse, the seperate adjustable thermostatic control cct. has a 30 amp relay in it's block. But my wiring harnesses fuse block has a 20 amp fuse which opened.......

Is it undersized? It's there to protect wiring.
Why did it blow?
Can I go to 25 or 30 amps? To match the other components protection. This fuce that opened really is in the control side not the load side, am I correct? Therefore should it see higher currents? Could it open if the fan runs too much? Looks like the fan cam off when the temp got down to 80 C after replacement of the fuse with the car still warm

Lastly, I do not know what my 16 inch puller fan is drawing when on or what initial start in-rush current is either.

Thoughts?

Tim