I live in a house that has CAT 5 cable in the walls running to wall plates in various rooms.
Would it be possible to remove the existing regular switch, replace it with a powered POE switch, and then plug in a POE device into one of the wall plates?
Also, for the non-POE devices already plugged into wall plates, would they be okay?
I’m trying to wrap my head around the interoperability of POE and non-POE and struggling.
Yes. There won’t be a problem, assuming that the devices in question are indeed ethernet devices and not just using cat5 wiring. That said you will need to be aware about what kind of PoE device you are plugging in. There are several evolutions of the PoE standard.
802.3af 802.3at 802.3bt
So make sure that if the devices requires 802.3at, the switch is rated to provide that.
And most importantly, you do NOT want anything that does passive POE, because it puts 48v on one of the pairs, which will zap any equipment not expecting it.
Good answer.
Just chipping in to point out that there are a LOT of products listed as “POE” that don’t comply with any official standard, and are just designed as a single pair for lower end devices. So to echo your advice, do check for standards before buying.
The idea was to swap in a Ubiquity POE switch so i could power a Ubiquity AP and some POE cameras throughout the house
Sounds good; known branded equipment is more likely to be compliant - but do check, it’s usually pretty clearly marked on packaging and listings.