HP Integrity BL870c Server-Blade - Manual (Page 11)

DC Power System Warnings
WARNING! To reduce the risk of electric shock or damage to the equipment, HP BladeSystem
DC power supplies must be installed in accordance with the following guidelines:
•
This product is intended to be installed only in a restricted access location.
•
This product is intended to be connected to a DC power source that can be classified as a
secondary circuit in accordance with applicable National requirements for Information
Technology Equipment. Generally, these requirements are based on the International Standard
for Safety of for Information Technology Equipment, IEC 60950-1.
•
The system is suitable for installation as part of the Common Bonding Network (CBN).
•
This product must be connected to a power distribution device that provides a means for
disconnecting power from the branch supply circuit. The power distribution device must be
provided with an over-current protective device suitable for interrupting fault currents available
from the main source.
•
The rack must be connected to site ground.
•
The green/yellow ground cable assemblies for enclosures in the racks must be connected to
the cabinet grounding rail. Do not rely on the rack or cabinet chassis to provide adequate
ground/earth continuity.
•
The Battery Return (BR) Input Terminals are considered to be an Isolated DC Return (DC-I).
•
Never connect cables to a terminal when there is power supplied to that circuit.
Cooling and Humidity Control
Do not rely on an intuitive approach to cooling design or to simply achieve an energy balance—that
is, summing up to the total power dissipation from all the hardware and sizing a comparable air
conditioning capacity. Today’s high-performance servers use semiconductors that integrate multiple
functions on a single chip with very high power densities. These chips plus high-power-density
mass storage and power supplies are mounted in ultra-thin server and storage enclosures, which
are then deployed into computer racks in large numbers. This higher concentration of devices
results in localized heat, which increases the potential for hot spots that can damage the equipment.
Additionally, variables in the installation site layout can adversely affect air flows and create hot
spots by allowing hot and cool air streams to mix. Studies have shown that above 70°F (20°C),
every increase of 18°F (10°C) reduces long-term electronics reliability by 50%.
Because of high heat densities and hot spots, an accurate assessment of air flow around and
through the server equipment and specialized cooling design is essential for reliable server
operation.
Consult with your HP cooling consultant or your heating, ventilation, and air conditioning (HVAC)
engineer.
NOTE: Failure of site cooling with the server continuing to run can cause rapid heat buildup and
excessive temperatures within the hardware. Excessive internal temperatures can result in full or
partial system shutdown. Ensure that the site’s cooling system remains fully operational when the
server is running.
Because each cabinet houses a unique combination of enclosures, calculate the total heat dissipation
for the hardware installed in each cabinet using the worksheet for the server you are installing.
Then add together the total heat dissipation values for all the cabinets in the system. For air
temperature levels at the site, see the temperature specifications for the server you are installing.
DC Power System Warnings 11