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High line voltage versus low line voltage
HP recommends that rack-optimized equipment is installed for operating at high line voltage (200-
240V AC).
Note:
The HP MCS can only be operated using high line voltage; however, rack-
mounted components can be operated using either high line or low line
voltage.
All HP products that are optimized for rack mounting have wide-range power supply inputs designed
to operate at a voltage range of 100-240V.
Benefits that support high line voltage operation of an installation are as follows:
• Power supplies run more efficiently and waste less power when operating at 200-240V, thus saving
electrical power.
• Greater power capacity in a single HP MCS. For the same size circuit, almost twice the power can
be delivered to an HP MCS at high line versus low line. For example, a 115V 30A branch circuit
can deliver 3450VA to an HP MCS, while a 230V 30A branch can deliver 6900 VA to an HP
MCS.
• Some products require 200-240V input power to operate at their full-rated capacity.
• Power supplies run cooler at higher input voltages and therefore will last longer and improve
overall availability. Also, because they run cooler, they produce less waste heat contributing to
lower cooling costs.
• Keeping input currents lower allows the use of smaller, more standardized power connections.
Grounding and Earth leakage current
For proper operation and safety, HP MCS components must be properly grounded in accordance
with any local and regional building codes. Furthermore, make sure that all power distribution
devices used in the installation, such as branch wiring and receptacles, are Listed or Certified
grounding-type devices.
The HP MCS is grounded. Ensure that the rack-mounted components are grounded as follows:
• For UPS products and PDUs that have permanently attached AC power cords or are directly wired
to the building power, the total combined leakage current should not exceed 5 percent of the total
input current required for the connected products.
• For UPS products and PDUs that have detachable AC power cords, the total combined leakage
current should not exceed 3.5 mA per PDU or UPS.
Additional resources
A power calculator is available at the following link:
http://h30099.www3.hp.com/configurator/calc/Power Calculator
Also available is a ProLiant Rack/Site Installation Utility for purposes of reviewing the server loading
to determine the number of power supplies for the power supplies to be redundant and approximate
the electrical and heating load per server for facilities planning. Please see the following:
http://h30099.www3.hp.com/configurator/calc/Site Preparation Utility.xls
There is also a quick reference power cord matrix available at the following:
ftp://ftp.compaq.com/pub/products/servers/proliantstorage/power-protection/powercordmatrix.pdf
Catalog.xls.
.
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