Site Preparation Guide, Second Edition - HP Integrity cx2620 Server

on equipment or applicable product-specific documentation for such devices to determine the
power required to support these devices.
NOTE: HP recommends that you have dedicated breakers for peripheral equipment.
Electrical Load Requirements (Circuit Breaker Sizing)
IMPORTANT: Local Authority Has Jurisdiction (LAHJ) and should make the final decision
regarding adherence to country- specific electrical codes and guidelines.
It is good practice to derate power distribution systems for one or more of the following reasons:
• To avoid nuisance tripping from load shifts or power transients, circuit protection devices
should never be run above 80% of their root-mean-square (RMS) current ratings.
• Safety agencies derate most power connectors to 80% of their RMS current ratings.
Power Quality
The intended source voltage for telco systems is -48 VDC. The server is designed to operate over
the range of -40 to -60 volts dc nominal. The server utilizes a dc to dc power supply to provide
stable operation with a uniform internal voltage. (Refer to the HP Corporate Power Standard
HP-00005-03 at http://standards.inet.cpqcorp.net/smc/hpstd/AHP0000503.htm.)
The servers are tested and shown to comply with EMC Specification EN50082. However, damage
can occur if these ranges are exceeded. Severe electrical disturbances can exceed the design
specifications of the equipment.
Sources of Voltage Fluctuations
Voltage fluctuations, sometimes called glitches, affect the quality of electrical power. Common
sources of these disturbances are:
• 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 server 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 a server power distribution system from other
circuits in the facility.
Electrical Factors 25