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Shield Terminal and Wire Color
What color wire and terminals we should use for cable shielding termination?

Someone can please clarify the color for shield wire & terminals we should use for cable shielding termination?

Thanks

By W.L. Mostia on 9 March, 2018 - 3:39 pm
1 out of 1 members thought this post was helpful...

You don't say what type of cables you are talking about, but for twisted-pair shielded cable, the shield (drain) wire is uninsulated and it is normally connected to a terminal labeled "S." Terminals for this type of cable are typically not colored other than the color you chose for all your terminals (grey, white, tan, blue, etc) and the signal wires are commonly labeled "+" & "-" for DC signals. Wires connecting shields to ground from a common point are typically green or green with a yellow stripe.

William (Bill) L. Mostia, Jr. PE
ISA Fellow, FS Eng. (TUV Rheinland)
WLM Engineering Co.

By Ikhtiander - on 9 March, 2018 - 10:06 pm
1 out of 1 members thought this post was helpful...

Hi Bhushanj,

Shield from instrument cable should be connected to instrument earth (IE) on one side, all of instrument cable will be consolidated and connected to instrument earth at control panel side.

Within control panel all of instrument cable shield should be provided with isolation with green colour and then consolidated at isolated grounding bar which is connected to plant instrument earthing system.

The other method, instead to connect the shield directly to control panel instrument grounding bar you can connect them to terminal block with green color, consolidated all if terminal blocks with jumper bar and then connect with single wire (use green wire as well) to control panel instrument grounding bar. In this case one should not use Green - Yellow ground terminal block since this type of terminal is clamped and shorted to the panel mounting plate via mounting rail which is the protective earth (PE), please use standard feed through terminal block with green colour.

Hope this will help you

Ikhtiander

By Bob Peterson on 11 March, 2018 - 9:26 pm
1 out of 1 members thought this post was helpful...

The Shield wire is almost always bare. A grounding type terminal is appropriate if you want to ground The Shield otherwise just a normal terminal if it's just a pass-through.

The shields can be bare if they are adjacent to grounded terminals, but if you don't want them grounded out accidentally use some green or clear heat-shrink