Rockwell Automation 1771-A1B_A2B_A3B_A3B1_A4B SERIES B Universal I/O Chassis Installation Instructions - Manual (Page 12)

Universal I/O Chassis 12
Publication 1771ĆIN075A-EN-P - March 2002
Connect Ground Bus to GroundingĆElectrode System
The grounding-electrode system is at earth-ground potential and is
the central ground for all electrical equipment and ac power within
any facility. Use a grounding-electrode conductor to connect the
ground bus to the grounding-electrode system. Use at minimum 8
AWG copper wire for the grounding-electrode conductor to guard
against EMI. The National Electrical Code specifies safety
requirements for the grounding-electrode conductor.
Ground Shielded Cables
Certain connections require shielded cables to help reduce the effects
of electrical noise coupling. Ground each shield at one end only. A
shield grounded at both ends forms a ground loop which could cause
faulty PLC-5 processor operation.
Ground each shield at the end specified in the appropriate
publication for the product.
Avoid breaking shields at junction boxes. Many types of connectors
for shielded conductors are available from various manufacturers. If
you do break a shield at a junction box:
•
connect only category-2 conductors in the junction box
•
do not strip the shield back any further than necessary to make a
connection
•
connect the shields of the two cable segments to ensure continuity
along the entire length of the cable
For more information about grounding the chassis, see Industrial
Automation Wiring and Grounding Guidelines (publication
1770-4.1).