HP Integrity rx5670, Site Preparation Manual

Page: 17 / 46

General Site Preparation Guidelines
Electrical Factors
Chapter 2
17
Raised Floor “High Frequency Noise” Grounding
If a raised floor system is used, install a complete signal grounding grid for maintaining equal potential over
a broad band of frequencies. The grounding grid should be connected to the equipment cabinet and electrical
service entrance ground at multiple connection points using a minimum #6 AWG (16 mm2) wire ground
conductor. The following figure 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/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.