This is a fishing expedition: I am intrigued by Powerline Networking and was wondering if anyone here has used it. I am primarily interested in Ethernet over 480VAC. A quick internet search is not showing anything....
It was a hot topic a couple of decades ago, but the implementations I saw had less than stellar performance, and that was way BEFORE the explosive growth of all of the SMPS and VFD technology that is putting a lot of harmonics on the lines now. I was indirectly associated with a company called Data-Linc that did this and although they still support their existing installations, in recent conversations I've had with them, it's something they no longer promote. It was just not reliable enough for most industries.
But it's still out there. Search for the terms Power Line Communications (which is unfortunately abbreviated as PLC), Power Line Networking (PLN), or for Ethernet, its sometimes called Broadband over Power Lines (BPL).
At a previous employer we had a shuttle car running off a bus bar, which would transmit 16 I/O over the 3 phase supply. Was very reliable never had any any major issues with the unit. Occasionally the brushes on the bus bar would require cleaning.
For data I have used many of the plug in 240VAC power line adaptors, these have been very reliable (TP-Link). Connecting TV, PC, set-top boxes, wi-fi extenders etc all without issue.