Grounding Procedures; System Grounding Procedures; Ground Conductors - GE 90-30 PLC Series Installation And Hardware Manual

Grounding Procedures

System Grounding Procedures

All components of a programmable logic control system and the devices it is controlling must be
properly grounded. This is particularly important for the following reasons.

Ground Conductors

Figure 2-10. Recommended System Grounding
GFK-0356Q Chapter 2 Installation
In addition to the following grounding information, we strongly urge that
you follow all applicable codes that apply to your area. For example, 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 mean injury or
death to personnel, damage to property, or both.
A low resistance path from all parts of a system to earth minimizes exposure to shock in the
event of short circuits or equipment malfunction.
The Series 90-30 PLC system requires proper grounding for correct operation.
Ground conductors should be connected in a tree fashion with branches routed to a central
earth ground point, shown in the figure below. This ensures that no ground conductor carries
current from any other branch. This method is shown in the following figure.
Ground conductors should be as short and as large in size as possible. Braided straps or
ground cables (typically green insulation with a yellow tracer - AWG #12 (3.3 mm
can be used to minimize resistance. Conductors must always be large enough to carry the
maximum short circuit current of the path being considered.
PROGRAMMING
DEVICE
Warning
SERIES 90-30 MOTOR DRIVES
PLC CABINET AND OTHER
ELECTRICAL
CONTROL
RACK
EQUIPMENT
RACK
EARTH CENTRAL
GROUND GROUND POINT
2
2
) or larger)
MACHINERY
NOTE
SIGNAL AND POWER
CONNECTIONS
ARE NOT SHOWN
2-11