Site Preparation Guide, Second Edition - HP Integrity cx2620 Server

• There are no daisy-chained receptacles, hot, neutral, or ground wires.
• The system is sourced from higher distribution voltages.
AC Power Quality Devices
HP products have a wide range of voltage tolerances. In general, approximately 10 percent of
the nominal voltage is sufficient for the marked electrical rated voltage. The best operating margin
is in the middle of this range. Your business needs will dictate the business risk you can withstand.
Although utility-fed AC power is usually error free, your particular building or area might be
subject to local problems.
HP recommends the use of uninterruptible power supplies (UPSs), backup generators, auto
transfer devices, floor-mounted distribution transformers (less than 75-foot distances), and other
alternatives for critical systems and applications demanding high availability. To ensure sufficient
power quality, keep in mind:
• The best voltage operating margin is in the middle of the distribution range.
• Higher availability equipment should have UPS sourcing and dedicated breakers.
• A few large UPSs provide more protection than numerous smaller cabinet UPSs.
UPS Recommendations
HP recommends the use of online versus offline UPSs for the highest availability environment.
HP does not recommend the practice of sourcing a cabinet UPS from a room UPS. This practice
can increase costs without providing more system availability. Indeed, this practice can introduce
more system downtime than just a room-level or system-level UPS. UPSs that are more compatible
with present-day technology generally use pulse width modulation (PWM) and have ratings
that are appropriate for a nonlinear load.
Power Consumption
Safety and regulatory labels on computer equipment list the ratings for maximum power
consumption conditions. Even though you will not normally reach maximum conditions, HP
recommends sizing all electrical distribution infrastructure to meet maximum conditions. It is
best to rate up rather than down. For example, if the marked electrical current is 16 amperes (A)
on a server, depending on your local electrical code, the electrical infrastructure should include
20-ampere receptacles, 20-ampere sized wiring, and 20-ampere breakers. Undersizing the wiring
might save costs in the beginning, but it will cause problems as infrastructure grows.
Average-sized wiring can be used with power quality devices, such as UPSs, but not with the
electrical infrastructure.
In determining the power requirements:
• Size electrical infrastructure for maximum rated consumption.
• Size air conditioning and UPSs with typical ratings, but realize that overloading might take
place with additional growth of the infrastructure.
NOTE: HP recommends that cooling be planned for maximum rated power output of the room
and that there is a growth plan for the cooling infrastructure.
Grounding Systems
WARNING! Follow electrical code when connecting equipment AC power ground wire to the
AC distribution point. Failure to properly ground the equipment or the floor can lead to shock
hazard.
HP computer hardware has been tested only on systems where protective earth is integral to the
electrical distribution system. This grounding is crucial for personnel safety and for maximum
equipment availability and use. Observe the following precautions:
22 General Site Preparation Guidelines