HP ProLiant SL270s HP ProLiant SL Servers Planning Guide - Page 23

see the applicable documentation for such devices. HP recommends using dedicated breakers for peripheral equipment. Electrical load requirements (circuit breaker sizing) IMPORTANT: LAHJ is the final authority regarding adherence to country-specific electrical codes and guidelines. HP recommends derating the power distribution systems for one or both of the following reasons: • To avoid nuisance tripping from load shifts or power transients, do not run circuit protection devices continuously above 80 percent of their RMS current ratings. • Safety agencies derate most power connectors to 80 percent of their RMS current ratings. Power quality Most HP products are designed to operate over a wide range of voltages and frequencies. The products are tested and shown to comply with certain EMC Specifications. However, damage can occur if these ranges are exceeded. Severe electrical disturbances can exceed the design specifications of the equipment. Factors affecting power quality Common factors that affect power quality include the following: • Electrical storms • Utility service brownouts or sags • Faults in the power generation equipment • Large inductive loads, such as motors and welders • Load fluctuations occurring within the facility distribution system • Loose connections or other faults in the distribution system wiring Power system protection HP products can be protected from the sources of many of these electrical disturbances by using the following: • A dedicated power distribution system • Power conditioning equipment • Over- and under-voltage protection and detection circuits • Lightning arresters on power cables to protect equipment against electrical storms The power distribution system is designed to provide immunity to power interruptions. However, testing cannot conclusively rule out loss of service. Use the following guidelines to provide the best possible performance of power distribution systems for HP computer equipment: • Dedicated power source-Isolates the power distribution system from other circuits in the facility. • 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. Power requirements and considerations 23