bill001g :
Ethernet is extremely low voltage and the wire are so thin that they would likely melt before any signification power surge could get though them.
Still it is almost impossible anyway. All ethernet cables are magnetically isolated from the equipment the are connected to.
#24 might sound thin but where microsecond scale surges are concerned, it is enough to pass hundreds of amps without warming up much, the same way house wiring can pass transients in the thousands of amps. If you look at PCBs for high pulse current with low duty cycle, the traces can be surprisingly thin when losses and efficiency are non-issues. It is all thanks to copper's high specific heat.
Not all Ethernet equipment is magnetically coupled. Some cheap NICs and routers use capacitive coupling instead and the capacitors they use are often only rated for 2-3kV instead of the 5-6kV from typical Ethernet transformers. Magnetically induced surges can go much higher than that, which is why you see some motherboards tooting 10-12kV of isolation on their Ethernet ports, the main goal of higher isolation rating being to let the induced voltage find somewhere else to jump to ground.