Home » Cable Screen shall not be Grounded at Field Device ?
Instrumentation Design

Cable Screen shall not be Grounded at Field Device ?

Why the Cable Screen shall not be Grounded at instrument field device?

Cable screen protects the signal carried on the conductor from external interference. Cable screen blocks the external interference and noise, then directs it to the ground.

Screen shall only be grounded at one source. The grounding is usually made in equipment panel or cabinet while field device point is left ungrounded and insulated. This is to eliminate the ground-loop current that may arise if screen is grounded at both end. In this case, the ground loop current becomes a noise for the signal conductor itself.

Why the cable screen shall not be grounded

Similar Articles:

Related Articles

Important Factors Consider during Piping Design

S Bharadwaj Reddy

DCS Controllers to Output Current Loops

S Bharadwaj Reddy

History of 3-15 psi, 10-15 mA, and 4-20 mA signals

S Bharadwaj Reddy

Pull Up and Pull Down Switch Circuits

S Bharadwaj Reddy

Top 10 Facts about HART Technology

S Bharadwaj Reddy

As per Process Conditions, Find out the Circuit Components Status ?

S Bharadwaj Reddy

1 comment

Salah March 17, 2018 at 7:25 am

What if the câble screen is grounded at cabinet, cut and insulated at the field device, but in the junction box the screen conexion is not covered, which means it can touch the interior surface of th JB, is that a normal situation? NB: it was build this way for all shielded cable s of many sites since day one

Reply

Leave a Comment

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More

WordPress Image Lightbox