Fault-Tolerant Ac Power Examples; Power Line Transients; Fault-Tolerant Ac Wiring Diagram - HP XP20000/XP24000 Manual

Fault-tolerant AC power examples

Figure 8 Fault-tolerant AC wiring diagram
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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 important that the receptacle
box be grounded with an additional ground connection that is separate from the dedicated ground.
The additional ground can be hard conduit.
Specific power plugs and receptacles are required for the DKC and DKUs depending on the power
option you specify when ordering the HP XP24000 disk array. The power cords on 60-Hz racks are
shipped with plugs attached. The power cords on 50-Hz racks are shipped without plugs. You are
responsible for having the correct plugs and receptacles installed by an electrician in compliance
with local 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 over voltage damage to equipment.

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.
XP24000/XP20000 Disk Array Site Preparation Guide 41