Wiring analog wires in a panel.

[jtashaffer]

How do you guys wire your 2 wire with a shield connections. Mainly I am talking about wiring up the shield wire for field wiring coming into the panel. I am wanting it to look nice and neat. At work we have some that go right to the PLC and the shied wire for each connection is wire nutted together hanging there. How do you guys do it.

 

[TConnolly]

I land all shields at one end only and only at the din rail terminals. I put a ground block between every four standard terminals so I have
+ - s + - + - s + - + - s + -
and each ground block gets two shields.

Most terminal manufacturers have a three level terminal block with a shield grounding terminal, but I rarely use them.

 

[jtashaffer]

With 2 shields in a ground block do you still have to run a ground wire to each ground block. I am assuming you probably do

 

[the_msp]

For lots of shields, I have seen earthing bar used. The field IO was going direct to Siemens ET200S. It was about a metre wide. The analogs insulation was stripped just enough exposing the shield which was attached via saddle clips to the pre-tapped earth bar.

 

[widelto]

I found this.

This belong to another forum, maybe this can help you.

 

[TConnolly]

If you use the din rail ground blocks they clamp onto the din rail bonding the block to the rail. Then I bond the rail to the panel ground. Those blocks cost a little more, but worth it IMO.

I've also elevated the din rail on standoffs and mounted a grounding bar underneath it. I didn't like that method as well though.

 

[nonuke]

This is what I use, and they look nice in a panel.
They are from Weidmuller, but Siemens, Phoenix, Wago etc. also have them.

 

[jtashaffer]

Tconnolly Could the din rail screw act as the bonding of the din rail if I use grounding blocks? If not I can bond them to the grounding strip

 

[the_msp]

I generally use these: http://uk.rs-online.com/web/p/non-f...22677633D4E4F4E45267573743D3532382D3933313526

...and run at least 1 wire to the main PE

 

[shooter]

The cable should be direct to inputs, the shield at this end can be with a heatshrink nicely hidden and isolated
at the cabinet entry use these grounding clips, but the rails should not be grounded directly, but via a wire, having the maximum thickness of any wire in this ground rails.
Now connect everything, check if the shieldrail is not having a ground loop, and connect the ground wire.
the ground wire should go to a central point with good ground connection.
here one or more wires should go to ground and one wire to each grounding point needed.

 

[TConnolly]

Tconnolly Could the din rail screw act as the bonding of the din rail if I use grounding blocks? If not I can bond them to the grounding strip

Are you asking about bonding the din rial itself through the backpan? A lot of people do rely on the backpan for bonding but I always run a copper bond wire, but attach it to only one grounding terminal on any contiguous piece of din rail. Its probably overkill, but that is how I do it.

 

[jtashaffer]

ok that sounds better than running a ground wire to each ground terminal block on the same din rail

 

[shooter]

The cabinet should not be used to make a connection to ground.
that does not mean the cabinet should not be grounded, but there must be a copper connection from the rail to the grounding connection, and also from this grounding to the cabinet.