One of the ‘outputs’ on the 12v side that you’re referring to in your link is the IR receiver. But since the link you provided us is so different it really doesn’t help much, the one you linked to really shouldn’t be buried up in an attic.
If your box has a typical metal junction box style knockout that you can put a strain relief on, that you’re probably okay to install it in the attic. If it says in the directions that it’s okay to do it or mentions screwing it to a joist, then you’re almost for sure okay, but still, I’d like to see a link to the one in question, not just a random strip of LED lights.
So, my questions from before are still standing. Can we get a link to the actual product and what are you actual concerns. Is there a reason you think you can’t do this? If there is, then maybe you shouldn’t.
Looks like you know what to do, OldOlds. One caveat though: I see that you are using “peel and stick” LED tape. That’s also what I used, but I took it one step further and also used Extruded Aluminium V shape Channel to make mounting easier and also for a heat sink for the LEDs (which really wasn’t necessary). After I got the first strip done and mounted, I tried to power it up, and the strip had shorted against the aluminum, and trashed those LEDs in that strip. Apparently, the adhesive used on the back of the strip was not insulating the back of the LEDs well enough. Fortunately, that strip wasn’t very log and I didn’t lose much.
After that, I discarded the aluminum channels and stuck the strips directly to the wood. Where the strip had to be attached to metal (under the microwave), I left the peel away backing on, and hot-glued the strip to the metal, preserving the insulation on the back of the LEDs.
Your strip may not have that problem, or you may be mounting only on wood.