Grounding Systems - HP Integrity rx5670 Site Preparation Manual

Grounding Systems

IT Power System
This product has not been evaluated for connection to an IT power system (an AC distribution system having
no direct connection to earth according to IEC 60950).
An hp Integrity rx5670 requires two methods of grounding:
• Power distribution safety grounding
• High frequency intercabinet grounding
Power Distribution Safety Grounding [LAHJ]
The power distribution safety grounding system consists of connecting various points in the power
distribution system to earth ground using green (green/yellow) wire ground conductors. Having these ground
connections tied to metal chassis parts that may be touched by computer room personnel protects them
against shock hazard from current leakage and fault conditions.
Power distribution systems consist of several parts. HP recommends that these parts be solidly
interconnected to provide an equipotential ground to all points.
Main Building Electrical Ground The main electrical service entrance equipment should have an earth
ground connection, as required by applicable codes. Connections such as a grounding rod, building steel, or a
conductive type cold water service pipe provide an earth ground.
Electrical Conduit Ground All electrical conduits should be made of rigid metallic conduit that is securely
connected together or bonded to panels and electrical boxes, so as to provide a continuous grounding system.
Power Panel Ground Each power panel should be grounded to the electrical service entrance with green
(green/yellow) wire ground conductors. The green (green/yellow) wire ground conductors should be sized per
applicable codes (based on circuit over current device ratings).
NOTE The green wire ground conductor mentioned above may be a black wire marked with green
tape. [LAHJ]
Computer Safety Ground Ground all computer equipment with the green (green/yellow) wire included in
the branch circuitry. The green (green/yellow) wire ground conductors should be connected to the appropriate
power panel and should be sized per applicable codes (based on circuit over current device ratings).
Dual Power Source Grounding
When dual power sources are utilized, strong consideration should be given to measure voltage potentials.
The use of dual power might create an electrical potential that can be hazardous to personnel and might
cause performance issues for the equipment.
Dual power sources might originate from two different transformers or two different UPS devices. Voltage
potentials from ground pin to ground pin of these sources should be measured and verified to be at or near 0.0
volts. Voltage levels that deviate or are measured above 3.0 volts should be further investigated. Increased
voltages might be hazardous to personnel, and should be further investigated.
Cabinet Performance Grounding (High Frequency Ground)
Signal interconnects between system cabinets require high frequency ground return paths. Connect all
cabinets to site ground.
Chapter 2
General Site Preparation Guidelines
Electrical Factors
15