Terminal usage

Rson · Jan 4, 2019

I just wanted to get some feedback here.

I started working with a new panel shop that thinks I’m using WAY to few terminals. I get out to the shop and find out that they are only using the top of the terminals – the bottom are completely empty.

The panel builder claims that our jobs are always empty on the bottom and that was a requested spec. I looked back and some other panels we sent there (from my predecessor) and he’s correct – all the panels are using only the top of the terminal block and the bottom is completely empty.

Personally, I’ve always been taught that terminals are just for connections outside the panel (or in this case for a door harness as well) I’ve always used the top/bottom of each terminal.

Is there any reason or have you heard of any company spec that says use one side only?

BlueAltezza · Jan 4, 2019

Well usually connections from a source/device (plc for example) to terminal array are connected on the top. The bottom of those terminals would be for the destination/device/external connections (drive for example).

Rson · Jan 4, 2019

Exactly my thought.

Looks like both were run to the top on all projects we did here in the past - bottom never used!

James Mcquade · Jan 4, 2019

Are you talking about a 2 stack terminal block that has 4 terminals?

if so, I would require they use the lower level terminals first leaving the top terminals as spares. this creates less confusion.

james

CLXlifestyle · Jan 4, 2019

I think it's good practice to have a dedicated "field duct" for terminals. In some cases, that might mean the bottom of the terminals. I'm with the panel builder. I have seen this in numerous specifications as well.

Ken Roach · Jan 4, 2019

To confirm: your panel shop is putting two conductors into the top of each Terminal Block, instead of one conductor on the bottom and one conductor on the top ?

That's like putting both your feet in your left shoe.

Or are you talking about terminals that are bus-connected together for distribution, where each conductor is placed in its own termination point.

For distribution, that sounds like a conservative practice that leaves plenty of room for future expansion and keeps conductors of a similar purpose in the same wireway.

I like to have external wiring come to one side, and internal wiring to the other. That seldom survives the connection of field devices, but we all have aspirations.

Rson · Jan 4, 2019

Ken Roach said:
To confirm: your panel shop is putting two conductors into the top of each Terminal Block, instead of one conductor on the bottom and one conductor on the top ?

That's like putting both your feet in your left shoe.

Or are you talking about terminals that are bus-connected together for distribution, where each conductor is placed in its own termination point.

For distribution, that sounds like a conservative practice that leaves plenty of room for future expansion and keeps conductors of a similar purpose in the same wireway.

I like to have external wiring come to one side, and internal wiring to the other. That seldom survives the connection of field devices, but we all have aspirations.

Yes, confirming your first scenario - only wires on the top - none on bottom.

Single-feed terminals.

Some terminals did have more than one wire in top - but most had a single wire in top.

Basically, instead of using the bottom of the terminal, they added a 2nd terminal of the same name with screw-jumpers. It nearly doubled the intended terminals in the panel.

OkiePC · Jan 4, 2019

I need a picture to help me understand why they would do this.

Rson · Jan 4, 2019

Here is an attached example.

I guess I can see the idea of it keeping the duct below it clear for field wiring.

I would almost like to find a multi-level terminal that has 2 connections on the top and 1 on the bottom in cases like this.

OkiePC · Jan 4, 2019

Rson said:
Here is an attached example.

I guess I can see the idea of it keeping the duct below it clear for field wiring.

I would almost like to find a multi-level terminal that has 2 connections on the top and 1 on the bottom in cases like this.

The picture is not showing up for me. Try resizing it. If you need a really good free photo editor, getpaint.net

AustralIan · Jan 4, 2019

It sounds like a requirement got confused somewhere. I agree that a sample diagram showing the connected devices would help, or rough General Arrangement.

scott.lawrence · Jan 4, 2019

internal panel wiring to the top of the terminals, external (including the door, if applicable) wiring to the bottom

Rson · Jan 4, 2019

Let me try again

jimtech67 · Jan 4, 2019

no Picture

Rson · Jan 4, 2019

Sorry about the picture thing.

They show up on my side, but when I check on the forum - nothing.

I'll get a zip file or something together later

Terminal usage

Rson

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Ken Roach

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