how to label a wire in control panel

Hi guys

a question about how to label a wire in control panel:
one guy told me that we must use same label for two ends of a wire.
if the the two ends of wire on two different drawing, for example, drawing 01, terminal 01 and another end on drawing 02, terminal 02, could we label one end as 01-01, and another end as 02-02, on the drawing, it will show 01-01 linked with 02-02?

Thanks

angi said:

Hi guys

a question about how to label a wire in control panel:
one guy told me that we must use same label for two ends of a wire.
if the the two ends of wire on two different drawing, for example, drawing 01, terminal 01 and another end on drawing 02, terminal 02, could we label one end as 01-01, and another end as 02-02, on the drawing, it will show 01-01 linked with 02-02?

Thanks

Click to expand...

Simplest and easiest way is "cross Ferrule".

e.g., At one end its TB and Other end it's PLC's Output channel 6 and that output card(Suppose it's 1794-OB32) is put in the rack at position-1 (Next To power/communication adapter).

So at TB side you'll write like this.: TB:BusBar Number,Terminal number/OB32,1:6
Where "6" indicates the channel number of OB-32.

AND

At Output card side(i.e., at the channel of OB-32), you'll write like this.
OB32,1:6/TB:BusBar Number,Terminal number.


Hope this will be clear to you.



~Mihir

I work at a machine design company as a controls engineer, and I used to wire control panels. I have seen variations from other companies, but they are usually companies from other countries. Anyways, working at 3 different companies we have always used the same wire number on both ends of the wire. If the wire goes from one page to another you just pick the line number from the first page it showed up on, or whichever one makes the most sense. For instance, if my 24vdc circuit starts on page 7 and line 20 then my wire number would be 0720. If I supply a device on page 3 and 10 I will still use 0720. I vary from this style of wire numbering for I/O. When I am working on the machine and I see a sensor, it benefits me to know what I/O point it goes to without having to open the drawing packet. On another note, you might drive your electrician nuts if you start having different labels on different ends of the wire.

Ive seen 3

cross ferrule, seems the most popular and makes the most sense to me.

Ive also seen the version JD states where each wire has its own #. Not a big fan of this one, id prefer cross ferrule.

I have also seen where the wire is tagged with its location. so if the wire end is on tb7 term 2, thats what the tag would say. IMHO this is a waste of time.

JDCROCKETT724 said:

On another note, you might drive your electrician nuts if you start having different labels on different ends of the wire.

Click to expand...

We have machines that are labeled like this.
Within 3 months just about each and every wireduct will be open (covers missing), each and every wire will be pulled out and our panels look like some of the worst pictures on the 'Control panels from Hell'-thread we have on here.

Mihir's way is one way you could do it.
But I prefer having the same nr on both sides of the wire.

We have this one panel. On one side of the wire it's got the reference number, page + line. On the other side it's got the contact nr of the contactor. Not so bad you'd think.
Except we have entire terminal strips with each and every wire labeled as one of the following A1, A2, 13, 14.
20+ A1's right next to eachother, 20+ A2's, etc etc.

The clever ones among you might say it won't be that bad if the order of the strips follow the order of the contactors. I'd agree. If that was the case.


The reason you supply wire numbers is to make troubleshooting easier. Not to annoy people.
Pls don't annoy people. They're the ones that'll call you at 3AM cause they are sick of trying to find what's wrong with the machine.

In the past, when all I did was locally connected machines, I have always used the method JD describes; same number, both ends, derived from the sheet#/line#. Most recently, in my latest endeavor, since most of the field devices are located at significant distances from the I/O racks, the cables were labled based on function, derived from the P&ID; i.e. a temperature transmitter tagged as TT1000 would have a cable starting at the I/O rack labeled TT1000, incremented at intermediate terminal blocks as TT1000-1, TT1000-2, etc., labeled the same at both ends of each respective cable. For the newest PLC panels, (we are in the process of replacing everything) we have gone (since the panel integrator has supplied them that way) to the cross ferrule scheme for internal panel wiring (took some getting used to, but it really does make the most sense) and maintained the field wiring to the devices based on device designator. Our panel drawings show all internal panel wiring labeled cross ferrule, and the field wiring is shown on a set of sheets as loop connection drawings, showing the PLC rack terminal-to-end device using the P&ID cable designation. Sounds a little confusing, but it really does clarify things overall.

As Jeebs pointed out, I have seen a lot of machines in the past with "20+ A1's right next to each other". Our panel integrator eliminates that by maintaining the TB numbering order for groups of terminals common-ganged together... the designations sitll show TB1-1, TB1-2, TB1-3, etc, even though these are jumpered together. Each wire still shows a different cross ferrule number, so there is no question as to which goes where.

I think both styles have their place. In my line of work we build maybe 1 or 2 of one machine and then move onto another. During debug wires get changed all the time. With our panels I would never label a wire to a terminal block because our electricians may decide they have a better way of routing a wire. I always defer to their expertise.

With that said, I think the other styles of wiring may be fine and be great for debugging if you have a product line where you are building a lot of the same panel that has been tried and trued to nail down the final wiring.

Like Jeebs said, keep your maintenance people happy. When I have a question on how to label or wire something I go straight to the electrician that has to work on my project. Keep them happy and you get to stay happy.

As bartonii said,
For internal panel wiring cross ferrulling is the best way. but when it comes to field instrument, u better prefer instrumentation tags.

whichcanultimately indentify at the panel end that that output is going to this instrument or input is coming from this instrument.

Same as instruments side u may label it's wire with plc's input/output channel/card/any reference. Which will make you comfortable to identify at both the end.

If the wires have numbers or names use them on both sides same wirelabel.
when making changes you can still use same labels.

If it's a wire number, then it is the same number on both ends of the wire. Otherwise, you are attaching terminal numbers to your wires. This is fine for knowing where the wire terminates on one end. Electricians would prefer to be able to identify where the other end of the wire is located when they are troubleshooting.

Ideally, your drawings should specify wire numbers in addition to terminal numbers. For practical purposes, wire numbers should be as short as possible. I'm an advocate of placing verbose text descriptions on the drawings and placing brief numbers on the wires.

KISS

This is a little like a previous question on drawing numbers. Over the years I have seen many systems, some very elegant and complex and logical - and totally a PITA for the poor schmuck with a multi-meter trying to find a problem at 10:00 PM. And having to match a ten or twenty digit wire number against a print isn't helping. If the print is missing (and yes, Virginia, it does happen) then an extremely clever but complicated system will be entirely unappreciated by said schmuck.

Wire numbers are there primarily to aid trouble shooting, and secondarily to assist the guy wiring the panel. Intellectual satisfaction for the engineer doesn't enter into at all.

We used a very simple system. Any wire or conductor that should always be at the same electrical state should always have the same number. In our case we used the schematic rung number of the first appearance of the wire. Terminal block are just conductors, and the terminal blocks, including field terminals, were identified with the panel side wire number that terminated there. The wire number showed up on both ends of the wire. A power supply "+" wire would always be "400" for example, on all drawings and on all wires that were tied to that point. If the wire passed through a device, like a switch contact, that changed its electrical state then it got a new number.

Our panel builders liked it, our engineers liked it, the field electricians liked it, and the guys doing commissioning and diagnostics in the field (including yours truly) liked it!

I've seen several ways.

I think the standard way to do it in the States is to label a wire based on it's origin in the schematics (sheet/line), and carry that numbering through everywhere. I've also seen wires labeled by the I/O address if they go to a PLC, but the only person this could conceivably help is the engineer, not the technician or maintenance guy. So I've started to base wire numbers off the line number of origin throughout the drawing set. I have seen for field devices where the wire number will be the tag number for the device that is switching it. So, for instance if I have a Pressure Switch called PS750423 on the P&ID, and it is labeled this way in the field, I'll use sheet/line on the hot wire going out to it but I'll call the wire coming back to the panel PS750423. That way there is no question where this wire goes to and what it's supposed to do. That works out better for retrofits in building systems. If it's a stand-alone machine and there's no P&ID for it then I just use the line number for all wire numbers, since the field devices will be labeled by the schematic line number anyway, and most of the time the wire numbers will incidentally fall into place.

I've worked on a lot of older European equipment and for some reason they used to NEVER label wires at all! I think their philosophy was, if you didn't have/couldn't use the schematic, then you had no business working on it. You are supposed to call a technician and pay them to fix it. I've noticed that European panels and machines tend to be designed with the philosophy that nothing will ever go wrong and it will never need repairs.

Problem is, things do go wrong and the awesome unbreakable machine is now incurring massive amounts of extra downtime because it is harder to fix, uses parts that aren't as available where the it was installed, and the main body of tech support is in a far-off land 5 time zones apart from you (Cue production managers who bought said machine on performance numbers only who are now upset with the extra downtime even though they never bothered to take these issues into consideration when purchasing).

Anyway, I've seen more and more wire labeling on European machines now, but even now it's not really the wire that is being labeled per se as it is a guide on the wire for where to hook it up to. That's fine, too. It does the job of telling you where to put it without having to look it up.

To answer your question as to whether or not you should label a wire the same on both ends: do whatever the people who are going to have to work on/troubleshoot it are used to. If they're used to having a different label on each end (unlikely), do it that way. But most likely they will be used to a numbering scheme like the one posted above by Tom Jenkins. So if that is the case (most likely it is), then do that.

Hi

To wire a panel to CE standard in europe you actually don't need wire numbers,
Now before anyone gets on my case I don't do this.
I see a lot of German wiring this way and it is the terminal number which is on the drawings that you are to use. I have a simple system ( i think) and it works for me. If a wire goes through a terminal or contact the number changes, this way a wire ALWAYS has the same number on both ends.
But with any system the drawings have to match what is actually there.


Donnchadh

For PLCs I stay sort of simple.
1st number is type:
1 = DI
2= DO
3= AI
4=AO

2nd is Rack number
3rd and 4th is Slot Number
5th and 6th is address

ie...100512 is a digital input (1), found at: rack 0 (0), slot 5 (05), input 12 (12)
This also helps when you are looking at logic.

If IO is not rack/slot based (like GE PLC) it is even easier..
I drop Rack/Slot location for the actually PLC input and wire number gets shorter..
2015 is output 15 and is also Q15 in logic.

The rest of the numbering is based on reference line of drawing, same way I reference all relays, switches, devices.
example..."601PS" is pressure switch found at reference line 601 in drawing, so now you know where "210MS" motor starter is found in drawing.

The drawing shows what terminals it goes thru by terminal strip number-terminal number labeling.

NetNathan said:

For PLCs I stay sort of simple.
1st number is type:
1 = DI
2= DO
3= AI
4=AO

2nd is Rack number
3rd and 4th is Slot Number
5th and 6th is address

ie...100512 is a digital input (1), found at: rack 0 (0), slot 5 (05), input 12 (12)
This also helps when you are looking at logic.

If IO is not rack/slot based (like GE PLC) it is even easier..
I drop Rack/Slot location for the actually PLC input and wire number gets shorter..
2015 is output 15 and is also Q15 in logic.

The rest of the numbering is based on reference line of drawing, same way I reference all relays, switches, devices.
example..."601PS" is pressure switch found at reference line 601 in drawing, so now you know where "210MS" motor starter is found in drawing.

Click to expand...

My problem with this is that using the wire number to reference a PLC address doesn't really help anybody but you, and it only helps you in a very minimal way, but it causes a lot of wasted time on the other end. Especially since in your particular scheme you don't have anything in the formatting that differentiates an address-based wire number from a schematic line number-based wire number. It may be obvious to you, but some guy in the field is going to open a box and see a wire labeled "2015." Is it an I/O address or is it a device on sheet 20, line 15? Even if he has the schematics, it's going to take some time to hash that out. If the numbering were consistent and always referencing a line number, it wouldn't matter. All he'd have to do is find that line number in the schematic. It's only a very minimal inconvenience to the engineer/programmer, who--if he or she is worth his/her salt--will have a copy of the schematics on hand. In the field, what PLC address a wire goes to is of very little importance.

Now that I'm thinking about it, it's strange that PLCs are singled out as something "special" as far as wire numbers are concerned. No other control devices change the wiring number scheme like that. It's strange.