To help vent hot air and bring in cool air, some enclosures are built with perforated front and rear doors, and vented roofs. Therefore, it is important to have a variety of choices in heights and depths when evaluating the cabinet design. With installations in existing buildings, there may be building shortcomings (no raised floor, low ceiling, concrete pillars in the room, etc.) that can influence the traditional 78-inch height of the network cabinet. Newer buildings are designed with tall network cabinets in mind, so you are beginning to see 9-foot network cabinets in these installations. Height, on the other hand, is often dependent on the room where the cabinets are located. One particular server is 40 inches (1,000 mm) deep and requires a 48-inch- (1,200 mm) deep cabinet, so the growth in depth is forcing a change in cabinet design. For instance, standard cabinets are at least 36 inches (900 mm) deep or even deeper. The trend towards denser rack-mount servers has affected network enclosure design, resulting in a need for deeper cabinets. But with this trend, as well as others in server technology, there are many network cabinet design considerations for installers to think about. Let us help you ensure safe, reliable, and efficient power distribution in your data center.The idea that technology is getting smaller, faster, and better is certainly one that can't be argued. We offer single-phase and three-phase PDUs in a variety of configurations, ranging from basic PDUs to switched, metered, and universal units. However, most circuit breakers have a delay that allows them to handle brief overloads when IT equipment starts up.Įnconnex has power experts on staff who can help you understand your requirements select the right rack PDU for your use case.
Additionally, PDUs that draw more than 20 amps must have built-in circuit breakers to protect the branch circuit wiring. In North America, rack PDUs and other electrical equipment must draw no more than 80 percent of the rated current of the plug. It’s important not to overload the circuit. A three-phase PDU can include 120V and 208V outlets to support both types of equipment for convenience and flexibility. In many cases, you’ll need to power 120V networking devices as well as more demanding servers. Therefore, it’s essential to understand what type of equipment you have in the server rack or cabinet and the type and number of plugs. This protects the IT equipment by preventing a 120V device from being plugged into a 208V circuit, for example. Similarly, device plugs will need to match the appropriate outlet on the PDU. The power cord for a three-phase rack PDU is thicker and heavier than one for a single-phase, but a three-phase unit reduces the number of cords required to provide the same amount of power. The rack PDU plug will need to match the outlet in the branch circuit receptacle. The current is determined by the thickness of the wire and the type of terminating receptacle. Three-phase branch circuits deliver more power and require a rack PDU that is explicitly designed for them. The voltage of each current drops to zero at different times, so the power supplied to the circuit remains consistent.
Three-phase circuits have three alternating currents that are out of phase with one another by 120 degrees. As a result, voltage drops to zero twice per cycle. Single-phase wiring is what you would find in any office or home - one alternating current flows through the circuit, reversing direction 60 times a second. The voltage depends in part on whether the circuit has single-phase or three-phase wiring. The load capacity of the branch circuit is given in volt-amps (VA) or kilovolt-amps (kVA) and is calculated by multiplying the rated voltage by the rated current. The wiring may run under a raised floor, in an overhead bus system, or both, terminating in an outlet near the server racks and cabinets. Following is a primer discussing some of the concepts involved.īranch circuits distribute power to server racks and cabinets from an electrical panel, switch, or distribution board. They provide monitoring, metering, and switched outlet capabilities that help administrators balance loads and remotely manage power requirements.Ī wide range of rack PDU configurations are available, and which you choose depends upon the input power architecture (number of phases, current, input plug type, etc.), the power consumed by the equipment in the server rack, and other factors. Today’s rack PDUs do more than bring power to IT equipment. Given 24x7 operational requirements and growing concern about power efficiency, the power distribution unit (PDU) has become an increasingly important part of the data center infrastructure.