HP StorageWorks XP20000 Disk Array Site Preparation Guide (AE190-96002, September 2007)

system errors or a complete system shutdown. If require d, an HP representative and your electrician can
determinethe currentlinevoltage andmakerecommendations. SeeChapter 3 Electrical specifications for
specific AC line voltage requirements.
Avoid the use of a line voltage conditioner.
Make sure that a power distribution unit (if used) provides the correct voltage to support your entire system.
Branch circui
tbreakers
See Chapter 3 Electrical specifications for specific b ranch circuit requirements for your power situation.
Single-phase branch circuit breakers
The power cords supplied are specified for connection to a single-phase, 20-amp circuit.
Frequency
Usually, AC line frequency is determined by your local power providers. In some cases, electrical power
is
supplied by 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 r
equires that the line frequency be within 0.5 Hz of the rated line frequency (50 Hz or 60
Hz). See Chapter 3 Electrical specifications for m ore information.
Safety and dedicated ground
The primary reason for grounding electrical systems is safety. The safety ground is require d by the
National Electric Code (USA) and most other local, regional, and national codes. In addition to safety
ground, HP requires that a de dicated (ear th reference) g round be installed as a common reference point
for a ll 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 ele ctrical subsystem must me et all the following conditions:
• Groundi
ng as
prescribed by your local countr y codes.
• An insulated grounding cond uctor that is identical in size and insulation m aterial and thickness
to the ungrounded branch-circuit supply co nductors. It should be green, with or without yellow
stripes, and is to b e installed as a part of the branch circuit that s upplies the unit or system. This
means t
he
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 ser vice equipment or other
acceptable building ear th ground such as the building frames (in case of a high-rise steel-frame
struc
ture).
• IT-configured grounding systems are not certified for use with the disk array as these grounding
systems may not have solidly conductor-connected grounded power systems and/or they may
have resistive impedance inserted in ground and/or neutral lines. The disk array requires a
solidly conductor-connected ground and may require a separate neutral in the case of WYE or
STAR connections. For HP disk arrays, T N grounding systems are preferred.
AC connections
The disk array primary rack has four separate connections to 200 VAC, single-phase, 20-amp p ower.
The second rack has two connections to AC power in the minimum configuration (four recommended)
and
four connections to AC power in the maximum configuration. Power requirements are 200 VAC,
single-phase, 20-Amps.
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