HP rp7400 Manual page 49

shock hazard may exist. For this reason, it is critical that a raised floor
be properly grounded.
Performance Drain
A raised floor acts as a voltage divider -- a capacitive plate -- and it may
create a performance issue for computer systems if improperly grounded.
Computer systems create both electrostatic discharge and
electromagnetic interference, and as processor speeds increase, these
effects increase as well. If the flooring system is properly grounded, the
metallic grids will act to dissipate the buildup of ESD and EMI.
49