A network tap device array capable of being powered by a power-over Ethernet (“POE”) supply is disclosed. The array enables data from multiple nodes in a communications network to be tapped and forwarded to a plurality of monitoring devices. In one embodiment the network tap device array includes a chassis that is configured to receive a plurality of network tap devices that are each powered by a POE supply. Each network tap device includes network ports for receiving and transmitting network data via communication cables and tap ports for forwarding the tapped network data to the monitoring device. In another embodiment, a sub-chassis includes a plurality of network tap devices and an aggregator that aggregates tapped data from each of the tap devices. The aggregator then forwards the aggregated data to the monitoring device. The sub-chassis can be included in a chassis that is configured to receive multiple populated chassis.