We had underground Cat 5 cable buried between 2 houses here on a run of about 200'.  The cable was underground cable and it was inside PVC conduit.  Lightning came in on it 3 times.  The first time it got a switch.  The next time it got a switch and the NIC in a laptop computer.  The last time It got every computer on the network (7 in all).  4 of the computers were saved, but 3 and a network laser printer were toast.  After the third hit, I talked with some local network installers and they said they no longer bury any copper Cat 5 cable at all.  It is not a question of if, but when lighting will find it.  We replaced the Cat 5 (the cable was ruined on the 3rd hit) with fibre optic.  It is more expensive, but lightning should not bother it.