Rockwell Automation Allen-Bradley SLC 500 Mode D'emploi page 11

Connect Equipment Grounding Conductor to Ground Bus
Connect an equipment grounding conductor directly from each chassis to an
individual bolt on the ground bus.
equipment
grounding
conductors
• use 2.54 cm (1in) copper braid or 5.2 mm2 (10 AWG) copper wire to connect each chassis, the
enclosure, and a central ground bus mounted on the back-panel
• use a steel enclosure to guard against electromagnetic interference (EMI)
• make sure the enclosure door viewing window is a laminated screen or a conductive optical substrate
(to block EMI)
• install a bonding wire for electrical contact between the door and the enclosure; do not rely on the
hinge
IMPORTANT
Connect Ground Bus to Grounding-Electrode 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 8.3 mm
the grounding-electrode conductor to guard against EMI. The National Electrical
Code specifies safety requirements for the grounding-electrode conductor.
ground
lug
star
bolt washer
Do not lay one ground lug directly on top of the other; this type
of connection can become loose due to compression of the
metal lugs. Place the first lug between a star washer and a nut
with a captive star washer. After tightening the nut, place the
second lug between the first nut and a second nut with a captive
star washer.
SLC 500™ Modular Chassis
ground bus mounting
ground bus
tapped hole
Grounding-electrode conductor
to grounding-electrode system
2
Publication 1746-IN016C-MU-P - December 2003
(8 AWG) copper wire for
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