LCN System Installation 4-1 9/96
4
SYSTEM GROUNDING
Section 4
Proper electrical grounding of the system equipment is presented here.
4.1 GROUND WIRING OVERVIEW
System-grounding requirements are specified in the LCN Site Planning manual. Both
Universal Stations and cabinets are prewired with the logic grounds and chassis grounds
already connected to the LG, HG, and Safety Ground connection points. At installation
time, the connection points must be wired to building steel or the appropriate ground stake.
In summary, system grounding consists of two steps:
• Step 1 is to ensure that the cabinet/station metal frame is grounded to ac-power
safety ground to protect personnel and to establish a good noise ground connection.
Connect the safety ground lug in each cabinet to the safety ground stake or
intermediate star plate. Use a separate wire from each cabinet to the connection
point. Only one star plate is allowed between any one cabinet and the safety ground
stake collection star plate, located just inside the building.
• Step 2 is to single-point ground Hiway Gateway (HG) cable shields to MRG. This
is only done when an HG is used without an HTD. This must be done if the HTD
is removed from the system.
4.2 GROUNDING LCN CABINETS AND UNIVERSAL STATIONS
STEP 1 Each LCN cabinet and station is equipped with a Safety Ground Terminal, see
Figures 4-1 and 4-2. It is recommended by Honeywell and required by many
codes, for personnel protection, that each cabinet and station be connected to
building steel or other designated safety ground before connecting ac power
wiring. Make sure that the safety wire (green or yellow green), if insulated, from
the cabinet and station frame ground post is connected to the safety ground
terminal block in the control room power panel, dedicated branch circuit power
panel, or building steel .
Cabinet Rear View
2689
Station Side View
Figure 4-1 — Safety Ground Terminal In Universal Stations and Cabinets
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