Comment by amluto

Not much? As I understand it, the major effects are in very long wires. Long wires can have get massive induced currents. But your homelab is unlikely to have long wires or very large loops. Ethernet wires are limited to 100m, and unshielded Ethernet is transformer-isolated to well over 1kV.

Shielded Ethernet could plausibly have issues with induced current on the shield. PoE might be less immune than ordinary Ethernet depending on what you’re doing with it, although well-behaved devices should be isolated. If you have a cable ISP, the cable shield might get toasty, although it’s likely to be grounded close enough to your house that any damage will be upstream.

Your 100% uptime will be tricky if your ISP goes down or you lose power.