C General Guidelines For The Computer Room; Power And Safety; Fire Protection; Power Quality And Protection - HP Cluster Platform Introduction v2010 Introduction Manual

C General Guidelines for the Computer Room

This appendix addresses some general site-planning topics that you might want to call out
explicitly in your site plan.
Caution:
Wire colors referenced in this section apply to installations in the USA. Substitute the appropriate
wire coding for your locale.
All electrical preparation work must be performed by qualified technicians. The polarity, voltages,
and grounding must be verified before any equipment is connected and powered up.
C.1 Power and Safety
Inside the computer room, fire protection and adequate lighting (for equipment servicing) are
important safety considerations. Federal and local safety codes govern computer installations.
Determine and specify the applicable standards, where not specified in this guide. Examples for
the USA are provided in the following sections.
C.1.1 Fire Protection
The National Fire Protection Association's Standard for the Protection of Electronic Computer
Data Processing Equipment, NFPA 75, contains information on safety monitoring equipment
for computer rooms. Most computer room installations are equipped with the following fire
protection devices:
• Smoke detectors
• Fire and temperature alarms
• Fire extinguishing system
• Circuit breakers
• An emergency power cutoff switch
• Devices specific to the geographic location, such as earthquake protection
C.1.2 Power Quality and Protection
Components in the cluster are designed to operate over a wide range of voltages and frequencies
and have been tested to comply with the standards described on their safety and regulatory
labels or specifications (see the component documentation). For example, EMC Specification
EN50082 might be specified for certain components. However, damage can occur if these ranges
are exceeded. Severe electrical disturbances can exceed the design specifications of the equipment.
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)
• Microwave, radar, radio, or cell phone transmissions
Computer systems can be protected from the sources of many of these electrical disturbances by
using:
• A Protective Earth (PE) connection with a wire diameter at least equal to the current carrying
conductors. The neutral conductor must not be used for the PE connection. (The PE wire is
green with a yellow stripe.)
• A dedicated power distribution system
• Power conditioning equipment
• Over voltage and under voltage detection and protection circuits
C.1 Power and Safety 51