What fuse to select for a 240W power supply
The biggest primary surge is power on.  Normally PSU's will store enough energy for 1 cycle dropout.  If solenoid pulse is near this duration yet &lt;= 10% of the primary voltage, it will also be &lt;= 10% of the 2ndary current, so this is trivial compared to surge for 1 cycle of storage power on startup that may or may not be much more than 3x the 240W.

The fuse isolates a fault and protects the wire and maybe some thermal failures, but cannot protect the electronics from every failure mode.

A good PS design protects itself so nothing needs to be added. CHeck the specs and suggested protection as required or your regional rules.

I suggest if you want to isolate a failure on a breaker, the PS ought to have a fuse recommended by the supplier.   3A Slo-blo may be suitable. I did not check elsewhere.