HP StorageWorks XP24000 Disk Array Site Preparation Guide, v01 (AE131-96002, June 2007)

Safety and dedicated ground
The primary reason for earth 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:
• Earth 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 HP system 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 HP system requires a solidly
conductor-connected ground and may require a separate neutral in the case of WYE or STAR
connections. For the HP system, TN grounding systems are preferred.
Receptacles
Each disk array cabinet has two or four separate connections to AC power.
• For disk array cabinets with two AC power connections, each input must be capable of supporting
the cabinet's entire current demand.
• For disk array cabinets with four AC power connections, the two inputs to AC Box 1 or the two
inputs to AC Box 2 must be capable of supporting the cabinet's entire current demand.
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