Proper use of ground conductor disconnect terminal blocks

[nonuke]

although you can use these terminals, they are specifically designed for supply voltage and not analogue control.
please pst the link to the site so I can look further

I agree with Iant. I only use this type of terminals for the control supply voltage (GTF76/230 from Phoenix contact).

For the 4-20mA analog inputs and outputs, I always use the normal disconnect terminals, so I can measure the loop current without opening the circuit.

 

[Kataeb]

I agree with Iant. I only use this type of terminals for the control supply voltage (GTF76/230 from Phoenix contact).

can someone please explain, why we need to disconnect the ground from a control supply voltage? what is the benefit of using the GTF 76/ 48 Phoenix Contact terminal block? thank you

 

[iant]

Kataeb.
Certain faults may need the control circuit isolated from earth. (Ground)

There are some requirements for a floating (non grounded) control circuit as well

It depends on your requirements and your specifications.

 

[iant]

If a control cct is NPN and you have a ground fault
That may hold the output on

 

[Kataeb]

our supplier replied as follows:

You can use the terminal block to test the presence of earth faults in the control circuit after the control transformer.
The terminal when disconnected will light up a red indicator if an earth fault is present.

This is in line with the requirement of section 9.4.3.1 of EN 60204-1/VDE 0113-1 for machine safety.

 

[iant]

That is normally used in LV AC control ccts.
As far as safety is concerned.
DC ELV CCTS are not required to be earthed but it is a very common practice.