Attention Europeans: Wire Numbering Question

According to IEC, the wire end can be tagged with three things.

Where it came from (termination), the Signal (which everyone here is equating to the wire number) and where it is going to (termination).


It does not have to have all three; it should at least have the where it is going to.

The termination number shall include all information about where it is going/came from; Tag number and terminal number.

For example, the wire going to relay 5001K1 on terminal A1 would be labeled [5001k1:A1]

This also applies to terminal strips; the wire going to TS10 terminal 5 is labeled [TS10:5]

You can even assign which side of the terminal the wire is connected to by adding for example 1 for top and 2 for bottom. Then the tag becomes [TS10:5.1]

I spent about three months becoming familiar with IEC format when a previous company switched over. Initially there was resistance but over time everyone became used to it and ended up liking it better than the "old way."

One of the big benefits comes when you have to replace a component; you can easily swap out a drive without having to refer to a schematic since all the wires are labeled with where they are supposed to go.

testsubject said:

For example, the wire going to relay 5001K1 on terminal A1 would be labeled [5001k1:A1]

Click to expand...

What is the wire labelled connected to terminal A1 on relay 5001K1 ???



So you are are saying that a wire going from a 24V + power supply to 100+ devices would have to have all the destination device terminations labelled on it, that's absurd.

A wire makes connections, connected points make a "net", and there is no need to describe where that "net" is connected to.

Every wire carrying the same electrical supply or signal should have the same number IMHO.

testsubject said:

One of the big benefits comes when you have to replace a component; you can easily swap out a drive without having to refer to a schematic since all the wires are labeled with where they are supposed to go.

Click to expand...

This is the best justification I've been able to find for wiring "by wire", and IMO, it's a terrible reason. If you're just replacing a device, you just take the wires out, and put them back right where they came from. Embrace you inner millenial and take a photo of the connections on your smartphone before you start if you need to. And even that aside, replacing components is not actually that common a task, when compared to the other tasks one might be doing in an electrical panel.

One of my clients has machines with the "by wire" scheme, and they're f***ing awful. There are hundreds of wires labelled "A2". The only schematic provided for this device is printed on a sticker on the back of the door. It's too small to read without a torch and some good eyesight, and half of them are faded to the point of complete illegibility. If you're trying to troubleshoot the machine, wire tracing is an absolute nightmare. You end up with all the wires out of the ducts and a huge mess, and it's still difficult.

On the other hand, machines wired by net can usually be traced and have basic troubleshooting performed even without a set of drawings, as long as you have half a brain for faultfinding.

Motor's not starting.
Find the motor contactor, it's not pulling in.
OK, wire number on the coil is 123, where would the other end of this wire be? Probably on an interface relay. There it is. Wire 123.
OK, is the relay on? No. Right, wire number on the coil of the interface relay is 456. Where's the other end of that going to be? Probably on an output module. There it is. Wire 456.
OK, output is on. So, output on, no relay on. I've probably got a failed relay, or there's an open circuit between the output and the relay. Multimeter on the relay coil, there's 24V on it, but it's not coming on. Cool, failed relay. Easy fix.

Now go through that process with no drawings and untraceable wire numbers. It's a disaster that ends up with every duct lid on the floor and a huge mess in the panel.

Right, I need to go and lie down now.

There are hundreds of wires labelled "A2".

Click to expand...

But this is obviously incorrect! Of course it cannot be that hundreds of wires would be labelled just "A2". If someone does choose to use the "by wire" approach, each wire that terminates at a different relay or contactor coil should have a unique lable on that end"-CR100:A2", "-CR101:A2", "-KM1.1:A2" and so on. Otherwise this whole thing is useless.

Oh, well that's much more useful. Now I know that this wire, which is terminated in terminal A2 of relay CR100, should be terminated in terminal A2 of relay CR100! I wonder where the other end is? Luckily for me, when I find it, I'll also find a wire number that tells me where I just found it!


/sarcasm

LadderLogic said:

But this is obviously incorrect! Of course it cannot be that hundreds of wires would be labelled just "A2". If someone does choose to use the "by wire" approach, each wire that terminates at a different relay or contactor coil should have a unique label on that end"-CR100:A2", "-CR101:A2", "-KM1.1:A2" and so on. Otherwise this whole thing is useless.

Click to expand...

To me, this sounds like someone trained by someone that could not read a schematic, and instead of learning taught his shortcut.


If there is a common run to all relays, contactors, PLC input cards, photoeyes, proxy sensors, pH probes, encoders, etc then they should ALL be labelled A2 as above. If you go to a device and it is getting +24V to ground, but not to A2 then wire A2 has a broken connection somewhere so jump it to a working A2.



The terminal way would be run a new wire through the machine from Encoder-Black to PS1-Neg or TB1-7(thru15)

LadderLogic said:

Otherwise this whole thing is useless.

Click to expand...

Yeah pretty much useles.

The argument (which I do not agree with) is that this numbering scheme is useful for replacing one component. You then know by the wiring numbers to which terminals the wireends must be connected to on the identical new component.

ASF said:

I wonder where the other end is?

Click to expand...

Say, at a PLC output module -A12, pin #5. So it would be labelled "-A12:5". Or, if it is one of the multitude of -24 VDC common connections, it might be "-X24.1:3.2". So it has to be terminated at terminal strip -X24.1, terminal number 3, connection point number 2. Provided all the DC commons land at terminal strip -X24.1 or whatever.

Yes, this all requires to have a proper schematic to find where the other end of the wire is. But I think one should better have a schematic with the "by net" labeling system, shouldn't they?

Of course I am getting you sarcasm. But I think many people do not seem to understand how the "by wire" system might work and why some people may prefer it.

As has been mentioned before, each wire end has to have a unique tag; there would not be 100s of wires labeled "A2."

I was "raised" on JIC; I can also see some of the benefits of IEC. The way they tag components is very straightforward.

I kind of liked having every terminal having a unique number: every terminal strip is labeled and all terminals in that strip start at 1. It really simplified the design.

I also agree that the iec style of labeling is useless. The end of the wire having a label of where it is landing on the component just seems useless. I also hate the way that they label components. The component labeling with no regard to drawing sheet is so confusing. If you have a relay K98 for example, there is no intuitive relationship of where that relay is in the drawings. You may have an index in the drawing package that you can go to, find k98 and read what sheet it is on, then go there.... I much prefer the sheet designated wiring and component labeling. Example CR120-33 ... Sheet 120, line 33 is where I would find it. Wire no 12033 is on same line, and that wire is labeled the same on both ends.

g.mccormick said:

I also agree that the iec style of labeling is useless. The end of the wire having a label of where it is landing on the component just seems useless.

Click to expand...

To clarify, that is NOT the IEC way of wire labeling.

What IEC 60204-1 says, is that any wire no must be defined in the schematics.

g.mccormick said:

I also agree that the iec style of labeling is useless. The end of the wire having a label of where it is landing on the component just seems useless. I also hate the way that they label components. The component labeling with no regard to drawing sheet is so confusing. If you have a relay K98 for example, there is no intuitive relationship of where that relay is in the drawings. You may have an index in the drawing package that you can go to, find k98 and read what sheet it is on, then go there.... I much prefer the sheet designated wiring and component labeling. Example CR120-33 ... Sheet 120, line 33 is where I would find it. Wire no 12033 is on same line, and that wire is labeled the same on both ends.

Click to expand...

That is not true: including the sheet number is perfectly acceptable in creating the component tag.

In my previous example, 5001K1 is the first relay on sheet 5001. This is acceptable to the standard.

The wire labels I generate also include the sheet number; I just do not use the line number. I do not like having to add a suffix to the number if there is more than one wire on a line.


I would like to add that I am currently using the wire numbering that most of you have been arguing for. I just spent a lot of time learning the IEC style and was passing on that information....

JesperMP said:

To clarify, that is NOT the IEC way of wire labeling.

What IEC 60204-1 says, is that any wire no must be defined in the schematics.

Click to expand...

testsubject said:

That is not true: including the sheet number is perfectly acceptable in creating the component tag.

In my previous example, 5001K1 is the first relay on sheet 5001. This is acceptable to the standard.

The wire labels I generate also include the sheet number; I just do not use the line number. I do not like having to add a suffix to the number if there is more than one wire on a line.


I would like to add that I am currently using the wire numbering that most of you have been arguing for. I just spent a lot of time learning the IEC style and was passing on that information....

Click to expand...

I am sorry to both of you. I admittingly do not know that actual IEC60204 rules. I was just passing on my experience of seeing/using panels from suppliers in europe.

JesperMP said:

To clarify, that is NOT the IEC way of wire labeling.

What IEC 60204-1 says, is that any wire no must be defined in the schematics.

Click to expand...

That is not complete; IEC 60204 details all safety rules.

IEC 61666:2010 establishes general principles for the identification of terminals of objects within a system.
In here it describes how all terminals must have a unique number; this includes terminal strips. No multiple 24V terminals without unique designators....

IEC 62491:2008 provides rules and guidelines for the labelling of cables and cores/conductors used in industrial installations, equipment and products, in order to maintain a clear relation between the technical documentation and the actual equipment and for other purposes.

62491 is where I derived most of the information I have been describing; it is very explicit that the wires are to be labeled with the termination point.

This is an acceptable wire label; TS12:1/24V/5001k1:A1
Source/signal/destination
That tells you everything.

And again, I am just trying to educate. I have done it both ways.....

So, after a little bit of investigation ...
IEC 62491 specifies several different alowable methods for wire numbering.

These possible methods are:
0. No marking. All wires can be followed visually.
A. Marking of the cable manufacturer. The wire no or color of the wire is used.
R. Identification marking. Each individual wire can be identified.
CL. Local connection marking. The wire end is identified by the connection point on the local device.
CR. Remote connection marking. The wire end is identified by the connection point on the remote device.
S. Signal marking. The wire is labeled with the signal it carries.

And you can combine several of those.

CL is NOT the method described previously by labeling the wire with only the connected device's terminal no (i.e. ":A1"). CL requires that you use the full name of the device (i.e. "=H22-Q3:A1").

"By net" would correspond to method S.
"By wire" would correspond to method R.

edit:
@testsubject, I did not remember exactly the IEC standard that defined wire numbering. IEC 60204-1 is the "mother" that refers to all the other standards.