Hi, i have design an Injector with LTC4279.
The Main Supply is Isolated From Netz with normal and regular Toroidal Transformer.
While the secondary DC/DC converter for have the 55 V Out for Injector Type1, Type2, LTPoE++...., isn't isolated, it's a normal Boost converter with choke.
It can be a proper PoE installation ??? (Attach the drawing)
Injector PSE Controller With dc-dc Not Isolated.PDF