I just received my 3 Nest Protects.
I currently have only 3 battery operated smoke detectors; one detector for the newly refinished basement was installed in an electrical box with the assumption it would be connected to the breaker in the future. The other 2 are standard battery powered, mounted to the ceiling with no electrical box.
I did not realize when I ordered, that backing plates were different for battery vs wired.
Is it possible to purchase a single wired backing plate so I can install this detector?
I used the old mounting plate from the existing detector. I made a cardboard template of the electrical box opening to fit the opening. Cut the old mounting plate to size, then drilled holes to mount it to the box. Then I used the Nest mounting plate to mark where the screws would go, and drilled pilot holes and slightly opened them up enough for the included screws to fit properly.
That's it in a nutshell, it did take some time getting the adapter I cut to fit exactly how I wanted, but overall, it came out pretty good.
I have the same problem and many others too. Not sure why does Google make different backplates for different versions of the Google Nest Protect that doesn't fit on to the ceiling. Just frustrating. There is no place where the backplates can be bought separately as well. Also surprised that no one looks at this issue.