NonStop S-Series Planning and Configuration Guide (G06.25+)

Site Planning and Preparation
HP NonStop S-Series Planning and Configuration Guide—523303-015
12-7
Considerations
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Contact your HP trained service provider for information about establishing a signal
grounding reference grid. A reference grid is highly recommended for systems
consisting of more than four enclosures.
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For information about IOAM power requirements, refer to Appendix G, Modular
Power Information.
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For systems that include more than two system enclosures, HP strongly
recommends using a three-phase AC power source. The electrical installation
should distribute all the single-phase enclosures among the three phases so as to
minimize the unbalanced neutral current. Consult a qualified electrician or facilities
planner for assistance.
•
A phase dropout contactor is not required for multiphase installations. NonStop
S-series servers have the ability to continue to power the system enclosures during
a short AC power loss. (See Power Failures on page 10-6.) A phase dropout
contactor would cause short outages to be stretched to long durations and would
require manual intervention to reset the contactor.
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For IOAM enclosures, a UPS is optional but recommended where a site UPS is not
available. You can choose to use any UPS that meets the IOAM enclosure power
requirements for all enclosures being powered by the UPS. One UPS option to
support the IOAM enclosure is the HP R5500 UPS. For additional information,
contact your HP trained service provider.
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If you are installing a system in a computer room in the United States of America,
an emergency power-off (EPO) disconnect is required by the National Electrical
Code. (See Emergency Power-Off (EPO) Equipment on page 12-11.)
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Convenience receptacles must be provided at the computer site for electrical
devices unrelated to the computer system. These convenience receptacles must
be labeled so that they are not mistaken for dedicated system receptacles.
Because devices connected to convenience receptacle circuits can feed noise
back into the power system, these circuits must not be fed from the computer
system power panel. If the installation site includes emergency disconnect
switches, they must also disable power to the convenience receptacles.
•
All outlets and circuit breakers should be clearly labeled to indicate the loads they
are intended to power. Examples of labels include “Group 01 PMF 50,” “Group 01
PMF 55,” “Tape 0,” and “Primary System Console.”
•
All outlets must be physically accessible to the operators who need to disconnect
AC power from the computer equipment.
Caution. Consult the documentation for any peripheral devices to determine if they have any
special power requirements.