As Andrew succinctly points out, while [shielded] Ethernet cables grounded at one-end only (like the Melco cable) or completely floating, does work to prevent ground loops, it causes the cable to behave as an Antenna for high frequencies which then couples to the signal carrying twisted pairs (especially with Gigabit Ethernet connections). Achieving the exact opposite results of what people typically use shielded cables for. So, not good.