Superdome Servers - I/O Expansion Cabinet Guide, Fifth Edition

Appendix B
Site Requirements
Power Requirements
208
Power distribution systems consist of several parts. Hewlett-Packard recommends that these parts be solidly
interconnected to provide an equipotential ground to all points.
The IOX and Superdome are safety grounded through the green (ground) wire in each AC power cord. In the
IOX, this ground passes through the AC power cord entry into the XPC and connects internally to the XPC
chassis. The XUC chassis and each ICE chassis are grounded through their respective DC power cords from
the XPC. When the power distribution safety grounds described below are correctly installed, no additional
external cabinet grounds are required.
Main Building Electrical Ground The main electrical service entrance equipment should have an earth
ground connection, as required by applicable codes. Connections such as a grounding rod, building steel, or a
conductive type cold water service pipe provide an earth ground.
Electrical Conduit Ground All electrical conduits should be made of rigid metallic conduit that is securely
connected together or bonded to panels and electrical boxes to provide a continuous grounding system.
Power Panel Ground Each power panel should be grounded to the electrical service entrance with green
(green/yellow) wire ground conductors. The green (green/yellow) wire ground conductors should be sized per
applicable codes (based on circuit over current device ratings).
Computer Equipment Ground Ground all computer equipment with the green (green/yellow) wire
included in the branch circuitry. The green (green/yellow) wire ground conductors should be connected to the
appropriate power panel and should be sized per applicable codes (based on circuit over current device
ratings).
Cabinet Interconnect Grounding
High-frequency grounding between IOX and Superdome is provided by the cabinet-to-cabinet signal cabling.
Additional low-frequency grounding is provided by the cabinet ground strap. See “Grounding the IOX to the
Superdome” on page 63.
System Installation Guidelines
This section contains information about installation practices. Some common pitfalls are highlighted. Both
power cable and data communications cable installations are discussed.
NOTE In domestic installations, the proper receptacles should be installed prior to the arrival of
Hewlett-Packard equipment. Refer to the appropriate installation guide for installation
procedures.
Wiring Connections
Expansion and contraction rates vary among different metals. Therefore, the integrity of an electrical
connection depends on the restraining force applied. Connections that are too tight compress or deform the
hardware and cause it to weaken. This usually leads to a short circuit that trips circuit breakers.
CAUTION Connections that are too loose will have a high resistance that will cause serious problems,
such as erratic equipment operation. A high resistance connection overheats and sometimes
causes fire or high temperatures that can destroy hard-to-replace components such as
distribution panels or system bus bars.