Cisco Systems MGX 8800, MGX 8900 manual C-10

C-10
Cisco MGX 8800/8900 Series Hardware Installation Guide
Releases 2 - 5.2, Part Number OL-4545-01, Rev. H0, May 2006
Appendix
Bonding and Grounding the Cisco MGX System
FigureC-2 Mixed Grounding System
TableC-1 Ground Point Descriptions for Mixed Grounding
Connection Description
Z1 –48 VDC return.
Z2 Protective earth or safety ground (green/yellow).
Z3 Equipment ground for non-isolated equipment.
Z4 Equipment ground for isolated equipment.
Z5 Equalizing frame ground. This ground creates low-impedance equalization
between frames.
B Battery ground.
1, 2, 3, 4 Connection points to the building’s ground system: a potential can exist
between these points within the ground system.
T Common-mode EMI filters.
Battery A
Nonisolated equipment
–48V-A
T
–48V-A –48V-A logic power
+–
–48V-B
1
1
B
2
B
T
T
Safety ground
Safety ground
Safety ground
–48V-A RTN
–48V-A
–48V-A RTN
–48V-B
–48V-B RTN
–48V-B
–48V-B RTN
Safety ground
Battery B
–48V-B
+–
Isolated equipment
–48V-A logic power
–48V-B
2
4
T
Z1
Z1
Z1
Z1
Z2
Z2
Z2
Z2
Z3
3
Z4
Z5
28311