Emerson Process Management ControlWave XFC - Manual (Page 163)

Section 3 - Grounding & Isolation Page 3-1 S1400CW
Section 3 - Grounding & Isolation
3.1 POWER & GROUND SYSTEMS
ControlWaves utilize DC power systems. AC power supplies are not provided with Con-
trolWave units. ControlWave, ControlWave MICRO, ControlWave EFM/GFC/EFC,
ControlWaveRED, ControlWaveREDIO and ControlWave I/O Expansion Racks are
provided with a Ground Lug that accommodates up to a #4 AWG size wire for establishing
a connection to Earth Ground. In the case of the ControlWaveLP, a Chassis Ground
termination terminal (TB2, Pin-3), that accepts up to a #14 AWG size wire, is provided on
the unit’s Power Supply/Sequencer Board.
3.2 IMPORTANCE OF GOOD GROUNDS
ControlWave units (see above) are utilized in instrument and control systems that must
operate continually and within their stated accuracy over long periods of time with
minimum attention. Failures resulting from an improperly grounded system can become
costly in terms of lost time and disrupted processes. A properly grounded system will help
prevent electrical shock hazards resulting from contact with live metal surfaces, provide
additional protection of equipment from lightning strikes and power surges, minimize the
effects of electrical noise and power transients, and reduce signal errors caused by ground
wiring loops. Conversely, an improperly grounded system may exhibit a host of problems
that appear to have no relation-ship to grounding. It is essential that the reader (service
technician) have a good under-standing of this subject to prevent needless troubleshooting
procedures.
WARNING
This device must be installed in accordance with the National
Electrical Code (NEC) ANSI/NEPA-70. Installation in hazardous
locations must also comply with Article 500 of the code. For
information on the usage of ControlWave units in Class I, Division 2,
Groups C & D Hazardous and Nonhazardous locations, see appendix A
of the applicable Customer Instruction (CI) manual. For information
on the usage of ControlWave units in Class I, Division 1, Groups C &
D Hazardous locations, see appendix B of the applicable Customer
Instruction (CI) manual.
3.3 EARTH GROUND CONNECTIONS
To properly ground a ControlWave unit, the units Chassis Ground (post or terminal) must
ultimately be connected to a known good Earth Ground. Observe recommendations
provided in topics Establishing a Good Earth Ground and Ground Wire Considerations.
3.3.1 Establishing a Good Earth Ground
A common misconception of a ground is that it consists of nothing more than a metal pipe
driven into the soil. While such a ground may function for some applications, it will often