Ethernet cables are specifically designed to block out electrical noise (shielded ones especially so), but they're not completely immune to it. Because of this, it's not a good idea to run your network cables close to your home's power wires. To counter this, Ethernet cables should be sufficiently far apart from power cables. There isn't a universal minimum distance, but generally, you should aim for at least 8 inches (20.3 cm) if both the Ethernet cables and power cables run in parallel. Lastly, make sure you never bundle the Ethernet cables and power cables together, as that's just asking for trouble.