ESD Protection for 1Gb Ethernet pre-magnetics able to withstand PoE?
The Rclamp0524 devices are incorrectly connected.
Usually Ethernet lines don't have ground-referenced ESD protection on the cable side of the transformer, you only see something like a TVS connected to both pins of a pair, if anything, and the Rclamp device would be on the PHY side of the transformer. On the cable side simple TVS between wires of a pair can be used, so there will be four of them, and they do not have to withstand the PoE voltage. Of course a special ESD device meant for protecting PoE enabled devices can be used.
Just for sake of simplicity, it says in the Rclamp datasheet that any pin to ground has a clamping voltage of 15V at 1A.
Notice that you have the Rclamp ground pins of all Ethernet pairs connected together, let's not call it ground for now, but common reference.
So due to the protection device, there can only have 15V from PoE+ voltage to common pin, and 15V from common pin to PoE- pin. So whenever PoE voltage of even 30V is applied, you would have clamping current of 1A via Rclamp devices.
In practice, as each diode has forward voltage of about 0.6V and the TVS has reverse breakdown at about 9.36V, it will start conducting at somewhere near 12V already.
So you must not reference or protect the ethernet pairs to ground or to each other, and with the Rclamp device, it does not withstand PoE voltages.