Single Point Ground (Spg); Vertical Ground Riser (Vgr); Vertical Logic Return Bar; Abbreviations And Acronyms - Nortel DMS-100 Series Maintenance Manual

1–4 Introduction

single point ground (SPG):

A single connection used to reference equipment or a system to ground.
In an ideal IBN arrangement, no dc current flows through the single point
connection unless a fault condition exists.

vertical ground riser (VGR):

A continuous conductor extending ground potential throughout the height
of a multifloor building. The size of this conductor is either 750 kcmil or
is equal to or larger than the largest conductor used for power distribution
in the building. The FGBs on various floors are connected to the VGR.

vertical logic return bar:

A copper bar mounted vertically inside several types of DMS frames and
used to reference the logic return to the LRB.

1.2 Abbreviations and acronyms

The following list is provided as a reference for a quick identification of
abbreviations and acronyms used in this document.
ac: alternating current
BPG: building principal ground
BR: battery return
BRR: battery return reference
CBN: common bonding network
CEC: Canadian Electrical Code
CO: central office
CPDC: cabinetized power distribution center
CSA: Canadian Standards Association
dc: direct current
DMS:
DMS SPG:
FBB:
FBE:
297-1001-350 Standard 02.02 August 1997
Digital Multiplex System
DMS single point ground
framework bonding bar
framework bonding equalizer