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097-55501-01 Revision M – January 2009
TimeHub 5500 User’s Guide 281
Appendix A Maintenance of Prior Master and Expansion
Shelves
In this appendix:
Making Ground and Power Connections
Making Ground and Power Connections–Expansion Shelf
Introduction
This appendix provides maintenance information for a master shelf prior to CLEI
D0MTP0K4RA and an expansion shelf prior to CLEI D0M1X00BRA since frame
ground was connected to the terminal blocks instead of directly to the chassis.
Making Ground and Power Connections
The TimeHub has redundant -48VDC power input connections labeled A and B.
Both are located in the upper-right and upper-left corners of the rear panel, as
shown in
. A separate frame ground lug is provided on the upper corner
of the side panel.
Grounding the Shelf
Frame ground connections are made on power terminal blocks TB1 and TB2 on the
rear panel of the shelf.
illustrates the terminal connections.
1. Run a cable from each ground terminal to earth ground. Use one 1.5 mm
2
/ 16
AWG green insulated wire to connect the ground terminal of TB1 to the frame
ground. Use another 1.5 mm
2
/ 16 AWG green insulated wire to connect the
ground terminal of TB2 to frame ground.
2. Crimp the supplied spade lug to one end of the 1.5 mm
2
/ 16 AWG wire and
connect it to the ground terminals on TB1 and TB2 (
).
3. Complete the ground connection using one of the methods described below,
depending on whether a ground rod is installed in the rack.
4. Using a digital voltmeter, measure between the ground and chassis and verify
that no voltage exists between them.