LSA panel used without pairs in mind - documentation howto?

[Grossel]

Hi.

In a semi old (built in late 70's and upgraded in early 90's) facility related to work, a LSA panel is used (similar to this). And I'm about to make a connector list, but there is an slightly issue.
The LSA panel addressing is made with pairs of connectors in mind. This one however have nothing to do with pairs, as each connector have it's own unique function.

SInce every address acually have 4 connection points (in left, in right, out left and out right) I can always made up a way to make documentation of the cable list. But before I do this, I just want to know if there is a standard way of addressing so that every cable connector (4 pr address) also get described ?

Thanks in advance

 

[rjenkinsgb]

For pairs (telephone wiring) the normal wire identification convention is 1A , 1B, 2A, 2B etc. through the ten pair locations in each strip.

The side of the strip with the "pips" is suppose to be the fixed wiring side (at the top) with the incoming cable fed up through the loop, then each core slotted between the appropriate pips as a guide so it comes straight forward and has some strain relief.

The lower side is supposed to be for loose patch wiring, between the various strips in a frame.
There is supposed to be enough free cable on the "fixed" side so the whole strip can be pulled out a few inches from the frame if needed; Krone make a wiring jig that fits to the frame and holds the strip a set distance out (approx 120mm from its seated position) while it's being wired on the fixed side.

The upper/lower contacts are connected with sprung leaves, which can be separated by plugging in a test connector, or used as a tap point for terminal blades on a protection magazine to connect with.

Depending how you want to do it, the two sides could be in/out, upper/lower, fixed/patch or whatever fits best.


This is one of the ID sheets we use - if it's suitable I can send you the original word document, or just use them as they are if you are not bothered about the name on them..

 

[Grossel]

Thank you very much, 1A - 2B seems reasonable.

I assume by "the pips" , you refer to the small plastic "offspring" just big enough to put a small tape with number on ?

 

[rjenkinsgb]

They are between the wire positions, to act as guides.
Photo below (a strip with a protection magazine plugged in as well), and the wiring jig just for reference.

The BT cable colour coding is like "base five" numbering, using sets of five colours; white is the A leg for the first five, then red the A for the next five, with the B leg colours repeating.

 

[Nigel Goodwin]

They are between the wire positions, to act as guides.
Photo below (a strip with a protection magazine plugged in as well), and the wiring jig just for reference.

The BT cable colour coding is like "base five" numbering, using sets of five colours; white is the A leg for the first five, then red the A for the next five, with the B leg colours repeating.

I asked an old mate of mine who worked for BT, years ago, how they dealt with the huge multi-core cables and the limited number of colours - he told me that they spiral in from the outside, with the few numbers of colours repeating continuously. I thought, OK if you're starting from a new bare cable, but not so much fun if you're trying to locate specific ones further in the future.

 

[Grossel]

I should have taken pictures. Anyway, in the facility, there are in particular two cables (that I remember):

• One 24 pair 0.35 mm² cable. Each pair is twisted and not two pairs have identical color combination.
• One 18 strands 0.75 mm² cable, all strands are common twisted (not sure how to put the words correct here) and so that some colors repeat, white and black does repeat. And there is no way to tell the difference between the two white strands.

 

[rjenkinsgb]

he told me that they spiral in from the outside, with the few numbers of colours repeating continuously.

Yep, one of the old standards only had three different pair colours - two adjacent different as a kind of directional index, then all the other pairs in that layer the same colour!
Then a loose ribbon wrap to separate them and the same over again for the next layer.

The newer stuff is a lot easier, 25 pairs all with unique colours then for larger cables each 25 pair set has a ribbon wrap using the same two colour number combinations to identify which bundle it is.
(Or some with a few pairs has tracer colours in the A wire, after the first 25 pairs).

I cannot find any info on the old style coding info online now...

I should have taken pictures. Anyway, in the facility, there are in particular two cables (that I remember):

• One 24 pair 0.35 mm² cable. Each pair is twisted and not two pairs have identical color combination.
• One 18 strands 0.75 mm² cable, all strands are common twisted (not sure how to put the words correct here) and so that some colors repeat, white and black does repeat. And there is no way to tell the difference between the two white strands.

It would be interesting to see the colours in use, there are quite a few different standards for identification.

Can you connect anything to the far end of the black/white cable? A pair tracer or just different value resistors temporarily across each pair could be used to ID them.

 

[Grossel]

Have to think a bit now - One of the issue is that the twisted cable (where same color appear twice) is not visible at one end (goes behind a wall before the twisting and outer insulation is visible). So even if there is a "twisted system" to be able to select the correct white, it have to be fully visible in both ends.

But in practice, there is no problem as I have a drum of RX 1.5 cable available so I can simply try, and then put some label when I find the correct strand

 

[dr pepper]

Here in the Uk A & B is refereed to as A leg and B leg.