Control panel wiring - terminals/daisy chaining

[ajph]

Hi all,

Wondering what is the preferred method for running power around the panel.

For example when building a panel if you have 24VDC from a PSU do you take it to terminals before going to each device/circuit breaker/fuse or just daisy chain between them?

Similarly, if you DO take to terminals for each item do you show each terminal on your drawings or just show it as a bus running through multiple pages and leave it to the panel builder to decide?

Thanks

 

[gclshortt]

It is normally taken to terminal strips in the panel depending on the number of contact points you have. Small panels may not need terminal strips. Labeling in the panel is the most important item.

I have seen drawings both ways. However I would not show each terminal on the drawing. Just label and leave to the panel builder.

Regards,
Garry
http://www.accautomation.ca

 

[ajph]

Thanks for the input.

What happens when you're using sequentially numbered terminals rather than terminals numbered as the same as the wire number?

I guess with this method of terminal numbering you would have to show each terminal in the drawing? What happens if the panel builder or maintenance need to put in a spare at some point?

 

[ajph]

Also related:

If you don't show all terminals on the drawing - what does your terminal list/plan consist of? Just external (field wiring, sensors, limit switches etc) connections?

 

[rkukl]

I require all common wires to be run to jumpered Terminal Strips or a buss bar. this includes + and - DC as well as Line Voltage. I have had too many issues with daisy chained wiring.

 

[ajph]

I require all common wires to be run to jumpered Terminal Strips or a buss bar. this includes + and - DC as well as Line Voltage. I have had too many issues with daisy chained wiring.

Yep I can see that daisy chaining is generally issue-prone.

How is this shown in your schematics?

 

[Friedrich]

Take a look at this board from Phoenix: https://youtu.be/4xCDssC_3F4
I use it a lot. Makes life simple doing both the schematics and wiring, plus you get a selective power distribution for your panel and external equipment.

 

[ajph]

Take a look at this board from Phoenix: https://youtu.be/4xCDssC_3F4
I use it a lot. Makes life simple doing both the schematics and wiring, plus you get a selective power distribution for your panel and external equipment.

That board looks pretty nice but I am more I inclined to use generic/easily sourable/replaceable parts.

For those of you that don't show every single terminal: do you provide any kind of terminal strip plan/list/table at all?

 

[The Plc Kid]

On this side of the pond Daisy chain wiring is listed as unprofessional by most people. I would not accept a panel with daisy chain wiring.

So to your question the proper way is to use termiansl and common wires that need to be with terminal jumpers for the specific termianl system you are using.

It's best practive to have a drawing of the termianl strip itself (pictoral) for panel building and fault finding but also place the terminal on the wire in your wiring diagrams with ther termianl number.

Many people use the wire number as the terminal number but I hate that myself. Best practice is to use sequential terminal numbers which can be used if you are doing several different terminal strips in different locations if it's a large panel like TS1 TS2 etc But I prefer to keep one long non repeating sequence even between different termianl strips.

That's my 2 cents worth.

 

[ajph]

Thanks everyone some good info here.

One thing I still don't understand is:

If I use a common block of terminals with a jumper bar for +24VDC these might be on the far left of my terminal strip. What is standard practise if I have an external connection to a field device (single multi-core cable) whose terminals are on the far right of my terminal strip?

Is it best to go from the common bank to another single terminal i.e. (common jumpered bank)->(single term)->(out to machine device)

 

[balash]

you could go with double layer terminals

 

[RET]

Hi all,

Wondering what is the preferred method for running power around the panel.

For example when building a panel if you have 24VDC from a PSU do you take it to terminals before going to each device/circuit breaker/fuse or just daisy chain between them?

Similarly, if you DO take to terminals for each item do you show each terminal on your drawings or just show it as a bus running through multiple pages and leave it to the panel builder to decide?

Thanks

Don't let the panel builder decide anything. Be specific.

For me: Yes, typically every device, power supply, and common is landed on it's own terminal. Some internal circuitry between i/o points and say interposing relays in the panel are wired directly. Just depends on the application.

 

[ajph]

Is it normal to take to a wire to another terminal from the jumpered strip in order to keep field device wiring close together? I.e a limit switch needs +24v & returns a signal but the common strip is too far away for a multi-core cable to reach? Or do you just cut each core to length?

 

[Bit_Bucket_07]

If someone daisy-chains power circuits in my panel shop, they will quickly find themselves terminated.

 

[ajph]

If someone daisy-chains power circuits in my panel shop, they will quickly find themselves terminated.

Is this always represented in your schematics? I.e every terminal shown?