[chbot] PCB Power Supply.

[Martin Towers]

For an idea of the surges likely this standard is interesting. It is
for 28V systems but it's an easy read, and free to download.
https://www.electronicproducts.com/understanding-the-mil-std-1275f-standard/

Unless you need to get serious about reliability I suggest a fuse
feeding a big fat TVS clamping below the limit for the SMPS. 
As usual, data sheets tend to mislead. For a TVS it's the energy rating
that's more important than the peak current. 
Martin