If your planning to run ethernet in the same conduit as power cables, this is not legal.
If separate conduit it is OK, but must adhere to local code as to the distances from other cables.
Now with my experience with ethernet between building, it not a good idea. A local lightning ground strike can easily jump to the ethernet cable, even if it is enclosed in metal conduit. I lost a wire, and switches as a result of running ethernet between building in a metal conduit; the cable was also protected with surge protectors which fried. Most of the issue is how fast the ground around the conduit disapates a lightning hit, the proper grounding procedures, and the voltage differential between the two endoints of the wire should lightning hit in the area (ground/building/powerlines).
Even if you have optical isolators on each end of the ethernet, there is no guarantee you will not loose equipement.
As to lightning, ethernet or shielded ethernet make little difference, once there is a high voltage differential it will get to the copper wire.
Best off running fiber.
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Chernobyl disaster..a must see pictorial