HP Integrity rx8620 Site Preparation Manual page 26

General Site Preparation Guidelines
Electrical Factors
Raised Floor "High-Frequency Noise" Grounding
If a raised floor system is used, install a complete signal reference grid (SRG) for maintaining equal potential
over a broad band of frequencies. The grid should be connected to the equipment cabinet and electrical service
entrance ground at multiple connection points using a minimum #6 AWG (16 mm) wire ground conductor.
Figure 2-1 on page 21 illustrates a metallic strip grounding system.
NOTE Regardless of the grounding connection method used, the raised floor should be grounded as an
absolute safety minimum.
HP recommends the following approaches:
• Excellent—Add a grounding grid to the subfloor. The grounding grid should be made of copper strips
mounted to the subfloor. The strips should be 0.032 in. (0.08 cm) thick and a minimum of 3.0 in. (8.0 cm)
wide.
Connect each pedestal to four strips using 1/4-in (6.0-mm) bolts tightened to the manufacturer's torque
recommendation.
• Better—A grounded #6 AWG minimum copper wire grid mechanically clamped to floor pedestals and
properly bonded to the building or site ground.
• Good—Use the raised floor structure as a ground grid. In this case, the floor must be designed as a ground
grid with bolted down stringers and corrosion resistive plating (to provide low resistance and attachment
points for connection to service entrance ground and HP computer equipment). The use of conductive floor
tiles with this style of grid further enhances ground performance. The structure needs to be mechanically
bonded to a known good ground point.
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Chapter 2