Wire Numbering

[MarkNightingale]

Some of the panels we get, especially from German suppliers, have no wire numbers at all.

It appears that some of our panels have no wire numbers, but if you look closely enough, they are printed on the cable itself.

Sometimes its really difficult to even see them, but they are there.

Cheers

Mark

 

[dogleg43]

We have a customer or two that use a FROM/TO numbering system for wire tags. Very difficult to troubleshoot between dyslexia and fat-fingered typing. Sucks.

 

[dwoodlock]

Pretty much all our panels are German, and none use wire numbers. At this point I am used to it, but I have had contractors in here for various things, and it often throws them for a loop.

The prints just reference terminal strip numbers and device terminals, as someone mentioned earlier.

 

[geniusintraining]

This is standard practice in my opinion.

A wire number should only change when it is being altered or switched in some way, whether that is through a push button contact, circuit breaker, disconnect, etc.

Agree, if its number 2 they all will be number 2 until they go threw another device, if you can ohm it out with the power off its the same wire and should have the same number

 

[OkiePC]

I worked in a panel last week where the OEM had notes on the old drawings stating that each wire shall be marked with the name of the device and its terminal number followed by the destination device and its terminal number. This resulted in wire numbers like this:
DCTB1-1/PS-1(-)

and the other end would be:
PS-1(-)/DCTB1-1

And that is the shortest label in the drawing which is simply what I normally call "DCCOM" or "22" or whatever line number it is when it first appears in the diagram.

Sounds good on paper, but in reality, it is pretty awful. Every terminal block, even when jumpered together, has a unique identifier. If you were to move a wire to a different terminal block in the same group, now the label is incorrect. Even the AC neutrals (all unique numbers due to the terminal number) ended up with 16 character wire numbers.

Whoever built and installed this panel only bothered to label about half the wires. They probably ran out of wire marker material. All I had to do was figure out all the mods that had been done in the past fifteen years and update the drawings.

I abandoned the requirement and went with good old straightforward I/O addressing for PLC stuff we added (SLC 5/05) and made my DC common (negative side) wires "DCCOM" instead of that other garbage.

Now if it were a battleship with dozens of compartments and I needed to trace those wires all over from end to end, it may have been handy, but not for a water plant...

 

[rpoet]

Schematics for the equipment I design and build almost always span multiple pages, even if the gear is only a single cabinet (we like to densely populate our cabinets).

To make it easier to build and troubleshoot, and to keep track of the page the part you're working on is from, I number schematic pages and wires like this:

EXAMPLE:
Schematics are plates 1.0 through 1.16

Wires that originate (and usually are only part of) plate 1.0 start at 0.0 and go up to 0.xxx

Wires that originate (and usually are only part of) plate 1.12 start at 12.0 and go up to 12.xxx

Occasionally, I'll end up with a set of wires in parallel (I do lots of theatrical LED lighting, and many dimmers double up on the common-positive output terminals for voltage drop reduction). In the case of parallel wires on plate 1.5, they'd be labeled 5.4A and 5.4B

The same wire number goes on both ends of the wire on a Brady wire label. All devices get a P-touch label on them, or the backplane is P-touch labeled if that's easier/necessary.

Often, you'll end up with wire numbers from one page spanning to others especially things like 24VDC and 120VAC control voltage - but you always know what page they originated from.


I too am of the belief that a wire does not change number unless it goes through a device, even if that wire branches out through a set of terminal blocks; 24VDC power is a perfect example of this.

Our shop guys seem to like this method, and it's a damn sight easier to troubleshoot when you've got your head buried up to your shoulders in a cabinet inside a piece of Broadway scenery that's full to bursting with equipment.


-rpoet

 

[kwade]

We have several older Italian machines here.
Their wire labeling for the 24VDC distribution:
'50' is '+' and '050' is '-' :for one subsection (i.e. logic control electronics)
'60' is '+' and '060' is '-' :for another subsection (i.e. operator control electronics)
'70' is '+' and '070' is '-' :for another subsection (i.e. motion control electronics)

The multiple 'x0' an '0x0' pairs are separately fused.
I may not have the correct numeric range for each subsection, but you get the idea.