Guidelines For Ground Connections - Siemens SIMATIC TI525 Hardware And Installation Manual

APPENDIX B – GROUNDING GUIDELINES
To achieve low impedance from device to single-point termination, 0.65
centimeter or larger ground braid should be used. A good rule of thumb is to
require less than 0.1 ohm of DC resistance between device and single-point
ground. This is accomplished by removing the anodized finish and using copper
lugs and star washers.
B.2.2

Guidelines for Ground Connections

Use particular care when establishing the ground connections. The following
techniques will help in establishing good electrical connections and increasing
system noise immunity:
D
Terminate grounding braid and green wires at both ends with copper
eye lugs to provide a good contact surface. Lugs should be crimped and
soldered.
D
Use #10 copper bolts (or equivalent) for those fasteners providing
electrical connections to the single-point ground. This applies to
device-mounting bolts and braid termination bolts for subpanel and
user-supplied single points. Tapped holes for these fasteners are better
than nut-bolt arrangements.
D
Paints, coatings, and corrosion can prevent good electrical contact at
ground points. Remove these impediments in the area of contact and
use external toothed lock washers (star washers) to ensure good
continuity and low impedance. This practice should be used for all
terminations — lug to subpanel, device to lug, device to subpanel,
subpanel to conduit, etc. Examples of ground connections are shown in
Figure B-1.
Hardware and Installation User Manual
Artisan Scientific - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisan-scientific.com Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
B-2