Phase Phase is used to describe the two main types of alternating current (AC) electric power produced by a utility, generator or UPS system. Single-phase power includes a single AC waveform, making single-phase equipment ideal for lower power density applications with per-rack power consumption levels up to approximately 2.8kVA (120V), 5kVA (208V) or 7.4kVA (230V). Three-phase power includes 3 AC waveforms, making 3-phase equipment better suited for intermediate and high-capacity applications with per-rack power consumption levels that surpass the practical energy limits of single-phase equipment. PDU Type Basic PDUs All PDUs including Basic PDUs provide reliable rack-mount power distribution for data centers, server rooms, and network wiring closets. Metered PDUs Metered PDUs monitor load levels to avoid potential overloads via a LCD display. Monitored PDUs Monitored PDUs remotely monitor voltage, frequency, and load levels via a built-in network connection. Wheelhouse Poster Template. Switched PDUs Switched PDUs can securely control individual outlets remotely to enable the rebooting of unresponsive equipment to minimize downtime.