That blog post is giving you excellent advice. You should never run standard Ethernet cable in the same conduit as AC power cables, especially from a solar inverter. The high-amperage DC and AC power will generate significant electromagnetic interference (EMI), which will severely degrade or completely kill your data signal. The correct ways to run the cable are: Use shielded Ethernet cable (F/UTP or S/FTP) and ground the shield at one end. Run the data cable in a separate conduit, keeping at least 12-18 inches of separation from the power cables. If they must cross, make sure they do so at a 90-degree angle to minimize interference. For a reliable, code-compliant installation, keeping the data and power runs separate is the most important rule. https://www.datatelaz.com/