Signals and PLC · Glossary

What is Cable Shield Grounding?

single point earthingSignals and PLC

Cable shield grounding connects the screen of an instrument cable to earth, normally at one end only, to drain noise without creating a ground loop.

Cable Shield Grounding Explained

For analog signals the shield is usually earthed at the control system end and left insulated in the field. Overall and individual pair shields are handled the same way.

High frequency and fieldbus networks may use both end grounding with equipotential bonding; follow the system maker rules.

Calculators for Cable Shield Grounding

CalculatorCable Loop Resistance CalculatorFree online calculator with formula and worked example.

Free Downloads

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Frequently Asked Questions

What is Cable Shield Grounding?

Cable shield grounding connects the screen of an instrument cable to earth, normally at one end only, to drain noise without creating a ground loop.

Why not earth both ends?

Different earth potentials drive current through the shield, inducing noise in the signal.

Should the drain wire touch the junction box?

No, keep it insulated and continuous through junction boxes to the earthing point.

Learn more on the blog

What is electromagnetic interference (EMI)

A practical guide on instrumentationblog.in with more detail on cable shield grounding and how it is applied on real plants.

Read Full Article

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