HP Server rp7405 Generic Site Preparation Guide - Edition 6 - Page 12

Power System Protection, Distribution Hardware, Wire Selection

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• Fluctuations occurring within the facility's distribution system • Utility service low-voltage conditions (such as sags or brownouts) • Wide and rapid variations in input voltage levels • Wide and rapid variations in input power frequency • Electrical storms • Large inductive sources (such as motors and welders) • Faults in the distribution system wiring (such as loose connections) • Microwave, radar, radio, or cell phone transmissions Power System Protection Protect the product from the many sources 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 the effects of undesirable transmissions • Lightning arresters on power cables to protect equipment against electrical storms Precautions are 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. Adherence to the following guidelines provides the best possible performance of power distribution systems for HP computer equipment: • Dedicated power source-Isolates a product power distribution system from other circuits in the facility. • Missing-phase and low-voltage detectors-Shut equipment down automatically when a severe power disruption occurs. For peripheral equipment, these devices are recommended but optional. • Online 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 conductors. 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 form part of the protective ground path for personnel and equipment. They protect the wiring from accidental damage and also provide a heat sink for the wires. The following types are acceptable: • Electrical metallic tubing (EMT)- thin-wall tubing • Rigid (metal) conduit • Liquidtight with RFI shield grounded (most commonly used under raised floors) • Armored 12 General Site Preparation Guidelines

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Fluctuations occurring within the facility’s distribution system
•
Utility service low-voltage conditions (such as sags or brownouts)
•
Wide and rapid variations in input voltage levels
•
Wide and rapid variations in input power frequency
•
Electrical storms
•
Large inductive sources (such as motors and welders)
•
Faults in the distribution system wiring (such as loose connections)
•
Microwave, radar, radio, or cell phone transmissions
Power System Protection
Protect the product from the many sources 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 the effects of undesirable transmissions
•
Lightning arresters on power cables to protect equipment against electrical storms
Precautions are 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.
Adherence to the following guidelines provides the best possible performance of power
distribution systems for HP computer equipment:
•
Dedicated power source—Isolates a product power distribution system from other circuits
in the facility.
•
Missing-phase and low-voltage detectors—Shut equipment down automatically when a
severe power disruption occurs. For peripheral equipment, these devices are recommended
but optional.
•
Online 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 conductors. 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 form part of the protective ground path for personnel and equipment. They protect
the wiring from accidental damage and also provide a heat sink for the wires.
The following types are acceptable:
•
Electrical metallic tubing (EMT)— thin-wall tubing
•
Rigid (metal) conduit
•
Liquidtight with RFI shield grounded (most commonly used under raised floors)
•
Armored
12
General Site Preparation Guidelines