HP Integrity rx7620 Site Preparation Guide, Fourth Editon - HP Integrity rx762 - Page 45

General Site Preparation Guidelines Electrical Factors • Circuit breakers • An emergency power cutoff switch • Devices specific to the geographic location, such as earthquake protection Lighting Requirements for Equipment Servicing Adequate lighting and utility outlets in a computer room reduce the possibility of accidents during equipment servicing. Safer servicing is also more efficient and, therefore, less costly. For example, it is difficult to see cable connection points on the hardware if lighting is inadequate. Adequate lighting reduces the chances of connector damage when cables are installed or removed. The minimum recommended illumination level is 70 foot-candles (756 lumens per square meter) when the light level is measured at 30 inches (76.2 cm) above the floor. Working Space for Server Access The recommended working space for performing maintenance on the server is three feet. The work space will permit at least a 90 degree opening of equipment doors or hinged panels. When planning for the working space area, consider whether access to the server will be at the front, the side, or the rear of the server. Power Consumption When determining power requirements, you must consider any peripheral equipment that will be installed during initial installation or as a later update. Refer to the applicable documentation for such devices to determine the power required to support these devices. Electrical Load Requirements (Circuit Breaker Sizing) NOTE 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 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 server is designed to operate over a wide range of voltages and frequencies. The server has been 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 Appendix B 31