When you install enclosures into a Network Equipment-Building
System (NEBS) compliant installation, each enclosure must have a reliable
electrical earth connection that is separate to any earth connections
provided by power supply cables.
On
system enclosures, this connection is made by using the front enclosure
mounting screws that are part of the standard installation described
in
Installing the support rails and
Installing the enclosures.
To provide a reliable electrical earth connection, the upright mounting
rails of the racks into which enclosures are installed must meet the
following requirements before installing the support rails and enclosures:
- Upright mounting rails must not be painted, oxidized or otherwise
insulated from the enclosure flanges and mounting rails. If paint,
oxidization or other insulation is present, it must be removed and
the metal must be brought to a bright, non-corroding finish.
- Upright mounting rails must have their own NEBS-compliant connection
to earth, independent of the earth connections provided by any power
supply cables.