Broadband Related > Telephony Wiring + Equipment

A little info please

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DANNYG:
After doing some decorating the two copper wires that come in to my property from the telegraph pole got disconnected the connection block was old and broken so i connected the wires to the cable that runs to the master socket.
My worries are the may be the wrong way round and with no identifying makes on the two black copper wires i have no way to tell.
would this have any adverse effects and is there a way to tell?
Many thanks for any help.

licquorice:
It doesn't matter which way round they are, telephony and broadband lines are not polarity conscious. Not since the days of party lines anyway  :)

tiffy:
Hi, welcome to the kitz forum.

This question would probably be best in the "Telephone Wiring + Equipment" section, however, no harm done and I'am sure one of the moderators will spot and move.

There are quite a number of ex BT engineers on the forum and at least one current engineer who are very well qualified to address your question, in the mean time and in lieu of their responses:

To the letter of the law the telephone/BB line up to the master socket should not be disconnected/re-wired, it's the responsibility of OR via your ISP, not sure what any charge implications would be considering that the current drop wire to internal wiring J/B has in fact fallen apart as you have stated.

My understanding:
The line has approx. 50v. DC across the pair. cores designated A & B, supply source, battery bank at the exchange.
Measured with respect to domestic earth, one line is approx. 0v., other line approx. -50v. DC, ie., the +ve line battery source is earthed at the exchange.
I can't remember which line is designated A or B, I'am sure someone will advise.

To answer your question regarding polarity, no, I don't believe it matters with modern telephone/BB equipment, either polarity should work.
However, please bear in mind the other points mentioned before proceeding with a more permanent repair.

Noted, reply by "licquorice" who is much more knowledgable on these matters while compiling.

Edit: Typo correction. 

burakkucat:

--- Quote from: tiffy on August 21, 2021, 04:20:07 PM ---I can't remember which line is designated A or B, I'am sure someone will advise.

--- End quote ---

The formal definition is that B-wire is the more negative of the pair.

How to check:

Connect the positive probe of a DVM to a good earth and test each leg of the pair with the negative probe. The B-wire will show around 50V DC and the A-wire around 2 to 5V DC.

tiffy:
@b*cat:

--- Quote ---The formal definition is that B-wire is the more negative of the pair.
--- End quote ---
Thanks for the clarification, was sure this would be within your remit!

So, to keep it simple for people like me, the A-wire is connected to exchange battery positive and grounded.
As already stated, somewhat hypothetical by present standards but still good to know.

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