Wiring a power supply, arduino, and LED strip together?
Sounds OK.

Things to pay attention to


Neat connections
EMI noise from floating 0V sources
Comm. Errors
strain relief for AC cord  ( plastic clamp to nearest frame screw)


How confident are you in attaching twisted stranded wire around closely spaced screws to avoid stray strands shorting out after getting neglected or yanked? 

Normally they use crimp lugs for AC input or you can solder tin the wire enough to wick a bit under the insulation then bend into a curl CW under screwhead.  Crimp lugs are cheap but simple skill requires crimping both insulation and wire so it is not exposed and survives a 2kg pull test easily.



Murphy's Law

Sometimes floating SMPS DC output that have common mode noise may cause USB serial port comm errors from noise leakage on USB to an earth grounded tower YET not to an earth grounded laptop since both are floating.    But it also depends they come from different AC outlets.  That's what I discovered visiting  the ECE lab at U of T.  One fix is to  add a  cap of 1nf to 10nF between EARTH GND and V-= 0V to bypass some SMPS CM noise issues that leak thru to the DC side..