HP rp5400 Site Preparation Guide - rp5400 - Page 12

General Site Preparation Guidelines Electrical Factors Power System Protection The hp server can be protected from the sources of many of these electrical disturbances by using: • A dedicated power distribution system • Power conditioning equipment • Over- and under-voltage detection and protection circuits • Screening to cancel out the effects of undesirable transmissions • Lightning arresters on power cables to protect equipment against electrical storms Precautions have been taken during power distribution system design to provide immunity to power outages of less than one cycle. However, testing cannot conclusively rule out loss of service. Therefore, adherence to the following guidelines provides the best possible performance of power distribution systems for hp computer equipment: • Dedicated power source-Isolates an hp server power distribution system from other circuits in the facility. • Missing-phase and low-voltage detectors-Shuts equipment down automatically when a severe power disruption occurs. For peripheral equipment, these devices are recommended but optional. • Online uninterruptible power supply (UPS)-Keeps input voltage to devices constant and should be considered if outages of one-half cycle or more are common. Refer to qualified contractors or consultants for each situation. Distribution Hardware This section describes wire selection and the types of raceways (electrical conduits) used in the distribution system. Wire Selection Use copper conductors instead of aluminum, as aluminum's coefficient of expansion differs significantly from that of other metals used in power hardware. Because of this difference, aluminum conductors can cause connector hardware to work loose, overheat, and fail. Raceway Systems (electrical conduits) [LAHJ] Raceways (electrical conduits) form part of the protective ground path for personnel and equipment. Raceways protect the wiring from accidental damage and also provide a heatsink for the wires. Any of the following types may be used: • Electrical metallic tubing (EMT) thin-wall tubing • Rigid (metal) conduit • Liquidtight with RFI shield grounded (most commonly used under raised floors) Building Distribution All building feeders and branch circuitry should be in rigid metallic conduit with proper connectors (to provide ground continuity) Conduit that is exposed and subject to damage should be constructed of rigid galvanized steel. 4 Chapter 1