Isolation Voltage rating of Ethernet Magnetics
No they are not rated, nor are they safe, for continuous mains voltage isolation, let alone 600VAC with perhaps thousands of amperes of fault current. Of course something custom could probably be made, but that would be silly.

Be sensible and install a media converter/fiber link and you will be safe (but still double check the materials and construction). I have used this method for hundreds of kV.