NonStop S-Series Planning and Configuration Guide (G06.26+)

Site Planning and Preparation
HP NonStop S-Series Planning and Configuration Guide—523303-017
12-8
Branch Circuits
Branch Circuits
Branch circuit requirements are:
•
All dedicated branch circuits supplying the system enclosures and tape drives must
originate from the same branch circuit breaker panel. HP highly recommends that
branch circuits for other peripheral equipment, such as system consoles, also
originate from the same branch circuit breaker panel as that for system enclosures.
This arrangement ensures a common ground reference for all enclosures, provides
the best likelihood of homogeneous power failures, and minimizes noise and
power transients.
•
Each branch circuit must include a phase, a ground, and a neutral conductor. The
ground conductor must be positioned inside the branch circuit conduit.
•
If duplex outlets are used, each half of each duplex outlet must be connected to a
separate circuit.
•
Two dedicated branch circuits are required for each system enclosure. Refer to
Appendix B, Specifications, for more information about the power requirements for
these circuits.
•
One dedicated branch circuit is required for each external tape drive. Refer to the
documentation for the tape subsystem you are installing for information about the
requirements for this circuit.
•
One dedicated branch circuit is required for each system console and each system
console. HP recommends that each system console and workstation be provided
with four receptacles originating from a single circuit breaker, so that related items,
such as a large screen monitor, an Ethernet switch or hub, a modem, or a printer,
can be easily connected. Normally, there are two system consoles on each
system.
•
System console outlet locations must be far enough away from enclosure outlet
locations so that enclosure power cords will not be inadvertently plugged in to a
system console outlet. Approximately 10 feet (3 meters) of separation is sufficient.
Uninterruptible Power Supplies (UPSs)
The power supplies in a system enclosure with a power shelf use power factor
correction (PFC). The uninterruptible power supply (UPS) system you use must have a
low output impedance to ensure the stability of AC power lines. The power supplies in
a system enclosure with a power shelf have been designed to work with most UPS
systems. However, if you choose a UPS system that uses ferroresonant transformers,
you must ensure that it is designed to work with power supplies that use PFC.
The output voltage of the UPS must be sinusoidal with a total harmonic distortion
(THD) of no more than 5 percent, and a distortion of any single harmonic of no more
than 3 percent. Do not use UPS systems with a square or trapezoidal output voltage
waveform.