Honeywell FSC-SM, Installation Manual, Page: 37 / 76

10/01 FSC Safety Manager Installation Guide 25
2.4 Cabling Considerations,
Continued
Spacing
It is recommended that noise creating sources (those with time varying
voltage or time varying current) be separated from data signal cable.
Cables with similar levels of noise susceptibility should be grouped
together, and those with similar levels of noise generation should be
separately grouped in trays and conduits.
IEEE 518 defines four classes of wiring that differ in signal level and
noise susceptibility as provided in Table 2-3.
Table 2-3 – IEEE 518 wiring classification definitions
Class Definition
Data 1 High noise susceptibility. Analog signals of less than 50 V and
digital signals of less than 15 V.
Data 2
Medium susceptibility. Analog signals greater than 50 V, regulating
signals of 50 V with currents less than 20 A; AC feeders less than
20 A.
Data 3
Low susceptibility. Switching signals greater than 50 V, analog
signals of 50 V with currents less than 20 A; AC feeders less than
20 A.
Data 4 Power AC and DC buses of 0-1000 V with currents of 20-800 A.
ATTENTION
Data 3 and Data 4 classes have one subclass each for
applications that require special cable and spacing. Table 2-4, Table 2-5
and Table 2-6 in this section list the subclass for Data 3—listed as Data
3A; the subclass for Data 4 is listed as Data 4A. Examples of Data 3A and
Data 4A subclass cables include:
• signals from communicating fields and line resistors,
• signals from shunts to regulators, and
• power greater than 1000 volts or greater than 800 amperes, or both.
Table 2-4, Table 2-5 and Table 2-6 list the recommended minimum
distances between trays, trays and conduits, and conduits, respectively.
The dimensions provided in the tables are between the top of one
tray/conduit and the bottom of the tray/conduit above, or between sides of
adjacent trays/conduits.
Trays containing Data 1 or Data 2 cables should have solid bottoms and
covers to complete shielding. Ventilation slots or louvers may be used
only in trays containing Data 3 cables.
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