Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 32)

Publication GMC-RM001A-EN-P — July 2001
2-14 High Frequency (HF) Bonding
Grounding (Safety Earth) Grounding refers to safety grounding and although the safety ground
circuit and the noise current return circuit may sometimes share the
same path and components, they should be considered as totally
different circuits with different requirements. The object of safety
grounding/bonding is to ensure that all metalwork is at the same,
ground (or Earth) potential at power frequencies.
The copper wire typically specified by regulatory bodies has little
effect at the high frequencies involved in noise problems.
Generally, safety dictates that all metal parts are connected to safety
earth with separate copper wire of appropriate gauge.
Most equipment has specific provisions to connect a safety ground or
PE (protective earth) directly to it.
These ground wires should be terminated directly to a bonded PE
ground bar, but lengths are not important provided the ground plane
strategy is followed (refer to the section The Ground Plane Principle).
ATTENTION
!
Safety ground circuits are extremely important and
all relevant local and international regulations must
be adhered to and take precedence over any
guidance given in this document.