I recently acquired a second P5 due to need for more outlets. Are there issues if I stack the second P5 on top of the existing P5 to save on shelf space?
I would not recommend this…the bottom P5 has the potential to cook the top P5.
If you have ‘no other choice’, space them as much as practical while keeping the distance to any shelf above in mind.
Heat kills components
Heat will be an issue if you stack them one on top of the other. If you have no other choice, you could insert an AC Infinity Aircom S8 or T8 component fan between the two P5s. Spec weight limit for items stacked on the S8 / T8 is 30 pounds, but might hold up ok. You could contact AC Infinity to confirm. P5 weight is around 37 pounds.