Allen-Bradley SLC 500 Manual Del Usuario página 10

Installation Instructions
SLC 500 Modular Chassis
1746-A4, -A7, -A10, -A13 Series B
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
ground
conductors
lug
bolt
use 2.54 cm (1 in) copper braid or 5.2 mm
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: 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.
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
for the grounding-electrode conductor to guard against EMI. The National
Electrical Code specifies safety requirements for the grounding-electrode
conductor.
8
ground bus
mounting
ground bus
tapped
hole
Grounding-electrode conductor
to grounding-electrode system
star
washer
13271
2
(10 AWG) copper wire to connect each
2
(8 AWG) copper wire