Appendix D - General Wiring Guidelines
In addition to the following wiring suggestions, we strongly urge that you follow all wiring and
safety codes that apply to your area or your type of equipment. In the United States, most areas
have adopted the National Electrical Code standard and specify that all wiring conform to its
requirements. In other countries, different codes will apply. For maximum safety to personnel
and property, you must follow these codes. Failure to do so can lead to personal injury, death,
property damage, or property destruction.
COLOR CODING WIRES
The following color codes are commonly used in industrial equipment manufactured in the United States. They are listed here as a
reference. Where they are in conflict with codes that apply to your area or your type of equipment, you should follow your
applicable codes instead. Besides satisfying code requirements, wire color-coding makes testing and troubleshooting safer, faster,
and easier.
Green or green with stripe– Ground
Black – Primary AC
Red – Secondary AC
Blue – DC
White – Common or neutral
Yellow – Secondary power source not controlled by the main disconnect. Alerts maintenance personnel that there may be
power present (from an external source) even if the equipment is disconnected from its main power source.
WIRE ROUTING
To reduce noise coupling from external sources, it is recommended you keep electrically noisy wiring, such as AC power wiring
and Discrete Output Module wiring, physically separated from low-level signal wiring such as DC and Analog Input module
wiring or communications cables. This can be accomplished by grouping separately, where practical, the following categories of
wiring:
Analog Input or Output Module wiring
. This wiring should be shielded to further reduce noise coupling.
Communications Cables.
Wiring such as Ethernet, USB, or serial communications cables should be kept away from
noise-producing wiring.
DC Input Module wiring.
Although suppressed internally, these low-level inputs should be further protected against
noise coupling by observing these wiring practices.
Discrete Output Module wiring.
These often switch inductive loads that produce noise spikes when switched off.
Where AC or Output wiring bundles must pass near noise-sensitive signal wiring bundles, avoid running them parallel with each
other. Route them so that, if they have to cross, they do so at a right angle. This will minimize possible coupling between them.
GROUPING MODULES
If practical, grouping similar modules together can help keep wiring segregated. For example, the left end of a unit could contain
Analog modules, the middle could contain DC modules, and the right end could contain AC modules.
©Sealevel Systems, Inc.
R4 Manual
39
SL9260 06/2015
