Table of Contents
Advertisement
2.4
Cabling Considerations
Introduction
Shielding
Table 2-2 – Raceway shielding
Raceway
Type
Free air
2 inch (5 cm) aluminum conduit
#16 gauge aluminum tray
#16 gauge aluminum tray
#16 gauge galvan. iron tray
2 inch (5 cm) IPS copper pipe
#16 gauge aluminum tray
#14 gauge aluminum tray
2 inch (5 cm) metallic tubing
2 inch (5 cm ) rigid galvanized
conduit
24
When installing an FSC Safety Manager System, it is important to
consider:
• conduit and tray shielding and spacing, and
• cable and wire classifications.
Conduit or cable trays should be used to route the network trunk line
within the plant for short distances or for several miles. The same conduit
should not carry both data and power wiring because of problems created
by electromagnetic interference (EMI). The choice of materials and
configuration for the cable conduit can determine the degree of protection
from this interference.
Table 2-2, showing raceway shielding, is taken from IEEE Standard 518
for the installation of electrical equipment. It compares different types of
conduits and raceways for magnetic field attenuation at 60 Hz and for
electrostatic attenuation at 100 kHz.
Thickness
mm (in.)
3.91 (0.154)
1.52 (0.060)
1.52 (0.060)
1.52 (0.060)
3.96 (0.156)
1.52 (0.060)
1.90 (0.075)
1.65 (0.065)
3.91 (0.154)
FSC Safety Manager Installation Guide
60 Hz Magnetic
Field Attenuation
Ratio
dB
1:1
0
1.5:1
3.3
1.6:1
4.1
3:1
9.4
3.2:1
10.0
3.3:1
10.2
4.2:1
11.5
6:1
15.5
6.7:1
16.5
40:1
32.0
100 kHz Magnetic
Field Attenuation
Ratio
dB
1:1
0
2.150:1
66.5
15.500:1
83.9
20.000:1
86.0
22.000:1
86.8
10.750:1
80.6
29.000:1
89.3
23.750:1
87.5
3.350:1
70.5
8.850:1
78.9
Continued on next page
10/01
Hide quick links:
Advertisement
Table of Contents
