S1400rsr.pdf, Guidelines for system grounding – Emerson Process Management Bristol Series 9110 User Manual
Page 59
Supplement S1400 / 1
Supplement S1400
Guidelines for
System Grounding
- Contents -
IMPORTANCE OF GOOD GROUNDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
GENERAL RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
TRANSIENTS AND INTERFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
TYPES OF EARTH GROUNDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
GROUNDING TECHNIQUES FOR 33XX SYSTEMS . . . . . . . . . . . . . . . . . . . 9
Several DPCs in Metal Cabinet w/ Power Supply . . . . . . . . . . . . . . . . . . . 10
Multiple DPC Cabinets w/ Local Supply in Each Cabinet . . . . . . . . . . . . 10
Multiple DPC Cabinets Powered by Single Supply . . . . . . . . . . . . . . . . . . 12
Multiple Clusters of DPC Cabinets Powered by Local Supplies . . . . . . . 14
IMPORTANCE OF GOOD GROUNDS
The equipment used with instrument systems must operate continuously within their stated
accuracy over long periods of time with minimum attention. Since many system sites are
unmanned and located in remote areas, failures resulting from an improperly grounded system
can become costly in terms of lost time. A properly grounded system will help to: prevent
electrical shock hazards resulting from contact with live metal surfaces; protect 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 relationship to grounding. It is
essential that the reader have a good understanding of this subject to prevent needless
troubleshooting procedures.
Warning
This device must be installed in accordance with the National
Electrical Code (NEC) ANSI/NFPA-70. Installation in hazardous
locations must also comply with Article 500 of the code.