A network tap device that is configured for operation in a copper Gigabit Ethernet communications network using a power-over-Ethernet (“POE”) electrical supply is disclosed. In one embodiment, a network tap device powered by a POE supply is disclosed, comprising first and second network ports that are configured with receptacles for receiving communication cables. The communication cables are configured to carry both data signals and the POE supply to and from the network tap device. The network tap device further includes first and second tap ports that connect with additional communication cables to a monitoring device. The network tap device also includes control and regulation circuitry that is configured to receive the POE supply from the communication cables via the network ports and to enable components of the network tap device to be operated by the POE supply.