HP StorageWorks XP20000 Disk Array Site Preparation Guide (AE190-96002, September 2007)

When receptacles are used to connect disk array components to AC power, they must include a
dedicated ground connection that is insulated from the receptacle. It is impor tant that the receptacle box
be grounded with a n additional ground connection that is separate from the dedicated g round. The
additional ground can be hard conduit.
Specific AC power cords and plugs are available to suit the power requirements and receptacles in your
location. You can specify the cords and plugs you need when you order the HP XP20000 disk array. You
are responsible for having the correct plugs and receptacles installed by a n electrician in compliance
with loc al electrical requirements and practices.
CAUTION:
When installing the receptacles, the electrician must ensure that each receptacle has its own neutral (if
required) and ground. Using the same neutral/ground for more than one circuit causes voltage loss
and heat problems and can create a fire hazard. A shared neutral conductor that fails open-circuit
can cause overvoltage dam age to equipment.
See Chapter 3 Electrical specifications for specific power requirements as well as plug and receptacle
part numbers and ordering information.
Power line transients
Heavy electrical loads from nearby machinery or equipment (for example, elevators or electric welders)
can
cause intermittent system problems with sophisticated electronic equipment, even if that equipment
is on a
separate circuit breaker. When faced with these conditions, provide a separate, completely
independent power panel with an isolated ground and circuit breaker coming directly from the main
building power source or secondary power source.
If necessary, an HP representative ca n measure your power line noise level and make appropriate
recommendations concerning the use of line treatment devices.
Protection against sources of electrical inter ference
The subsequent table lists ways to protect the disk array from sources of electrical interference.
Potential source
Description
Wall outlets
Convenience power outlets for building maintenance equipment (such as vacuum
cleaners and floor buffers) must be wired from circuit breakers on a power panel
separate from the computer system panel. The ground wires from these outlets
must be connected to the n ormal building distribution panel and not to the system
ground. If a separate power source and separate ground are not provided,
operation of janitorial equipment can induce electrical noise and cause abnormal
operation of the computer system. Your electrician can verify whether maintenance
outlets are on separate panels.
Lightning
In geographical areas subject to lightning storms, it may by advisable to install
lightning protection for both personnel and computer systems. The principles of
lightning protection and personnel safety are outlined in detail in the lightning
protection code contained in the National Fire Protection Association (NFPA)
Handbook.
Electromagnetic
interference
The disk array is specifically designed to reduce its susceptibility to radiated and
conducted interference. Electromagnetic interference can cause a variety of system
problems. An HP representative can advise you about the m ost common causes of
electromagnetic interference.
Uninterruptible power supply (UPS)
Most disk array units are installed in data centers where a U PS strategy is already in place. However, if
you are making your first large disk array purchase, you may need a separate U PS solution.
30 Site requirements