I'd not have thought a 100 uF would do that.
Energy content at say 15V is very small so inrush time very limited so
absolute energy in fuse small.

But, based on ESR alone, peak inrush current can be large.

ESR of eg Panasonic FT V SMD 100 uF, 15V cap  is 0.34 Ohm.

https://industrial.panasonic.com/cdbs/www-data/pdf/RDE0000/ABA0000C1240.pdf

Peak inrush current from a suitable source can notionally be tens of Amps -
for a very short period.
A power supply rated at say 1A MAY have an output capacitor able to source
much higher currents very briefly.

If you can tolerate the drop from a 1N400x diode then maybe a small amount
of added series resistance may help.
Changing to a Schottky diode recovers part of the drop - but odds are a
small resistor that may make the difference will not add enough drop to
affect normal operation.

Using say 3R3 with about 350 mA usual peak adds about 1V drop - but
increases your effective ESR by a factor of about 10 - and drops your peak
inrush to around 4A at 12V. All very approximate but perhaps worth looking
at the several contributors with a scope.
How much instantaneous current will the supply source?
What is the peak worst-case real world inrush current?
Does the fuse have a peak current duration versus blow time graph or
formula?


 Russell



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