Figure 1-61. Example of Unacceptable Grid-to-Pedestal Bonding
Connections to the raised floor system. Connections from the equipment racks and the earth
electrode subsystem to the floor are important. Clamps, if used, should be installed on the upper pedestal
assembly to avoid the relatively high resistance between the lower assembly (that has the base) and the upper
column. The stringer to pedestal fastener hardware can often be changed to allow bolting a bonding cable
terminal directly to the pedestal head. It is feasible to obtain additional grid locking hardware and use it to
bolt the bonding cable terminal to the floor grid. Another means of terminating a bonding cable is to drill a
hole and bolt it to a non-heavy weight bearing stringer.
Corrosion control. In extremely humid environments where corrosion is common, the use of
corrosion prevention compounds is recommended. Bolted joints can be covered with a non-corrosive silicone-
rubber compound that will protect the joint for the life of the installation. An ice cube rubbed on the silicone-
rubber will smooth it.
Carpeting. Carpeting selected as a floor-covering, should be of a low static or static-free type to
prevent possible static discharge or component failure. See MIL-F-29046 for additional information.
Maintenance measurements. To determine degradation of the floor, resistance measurements and
method should be documented and available so that repeat measurements can be made if ground reference
subsystem problems are suspected or periodic checks for degradation made.
Reliability. The MIL-F-29046 specification provides information for raised floor procurements.
The guidelines in this Handbook will provide a ground reference subsystem that is well-designed, properly
installed and lasts for the life of the electronic system installation.