User Manual

36 Part 003609A revision 01 December 16, 2002
Amosphere NPM Installation Procedures (WCS)
Isolated Ground Plane Environment
Ensure that the NPM will be installed in an isolated ground plane environment
as defined in Telcordia Technologies GR-1275-CORE.
Master Ground Bar Requirements
The site’s master ground bar (MGB) must be connected to the building principal
ground’s electrode system. The building principal ground is the point where
grounding conductors of the building (such as air-conditioning, communication
systems, and structure) are bonded together.
Ensure that the electrode system meets the requirements specified in the National
Electrical Code (NEC) article 250, sections 150–170, 1999.
NOTE: See the floor plan drawing in your E1 package for the
location of the MGB.
Ground Riser Cable
The ground riser cable (the cable connecting the MGB to the building principal
ground) must have a minimum conductor sizing of 2/0 AWG. If any equipment
cables at the site are larger than 2/0 AWG (such as to compensate for voltage
drop), the size of the ground riser cable must be adjusted. The ground riser cable
must use an equal or larger gauge than the largest conductor. The ground riser
cable must be labelled with a tag conforming to GR-1275-CORE.
In order for the ground riser cable to be nonrestrictive to lightning, the following
guidelines should be observed:
 The cable should be run using the most direct route possible. The
number and severity of turns and bends should be minimized. Bends
must not exceed 90°.
 The cable must not be looped or coiled.
 The cable must not be supported by metal clamps.
 If a conduit is required to protect the cable, the conduit should be made
of PVC. If a metal conduit is used, the conduit must be bonded to the
ground riser cable on both ends.
 The cable must not run through or enter any metal boxes unless the
boxes are bonded to the ground riser cable at the entry and exit point.