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HP StorageWorks XP12000 Disk Array Site Preparation Guide
Frequency
Usually, AC line frequency is determined by your local power providers. In
some cases, electrical power is supplied by motor-generators. Shifts in AC
line frequency can cause system errors. An HP representative can monitor
the frequency of the input AC line power and make recommendations, if
necessary. The disk array requires that the line frequency be within 0.5 Hz
of the rated line frequency (50 Hz or 60 Hz).
See
Appendix A
for more information.
Safety and dedicated ground
The primary reason for grounding electrical systems is safety. The safety
ground is required by the National Electric Code (USA) and most other
local, regional, and national codes. In addition to safety ground, HP
requires that a dedicated (earth reference) ground be installed as a common
reference point for all system components. Consult with an HP
representative and your electrician to ensure that your electrical system
meets all local and national safety codes.
Grounding requirements
Your site’s electrical subsystem must meet all of the following conditions:
• Grounding as prescribed by your local country codes.
• An insulated grounding conductor that is identical in size and
insulation material and thickness to the ungrounded branch-circuit
supply conductors. It should be green, with or without yellow stripes,
and is to be installed as a part of the branch circuit that supplies the
unit or system. This means the ground conductor must be run in the
same conduit, armored cable, or other cable bundle as the phase wires.
• The grounding conductor should be grounded to earth at the service
equipment or other acceptable building earth ground such as the
building frames (in case of a high-rise steel-frame structure).
• IT-configured grounding systems are not certified for use with the disk
array as these grounding systems may not have solidly
