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Thread: Wiring help needed please - phones

  1. #1
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    Default Wiring help needed please - phones

    Hi,

    I've read the other posts on this topic so please - no links.

    I have my phones wired in the correct colour coding of B/w-2, W/b-5, O/w-3 (for extensions) but I think the numpty who owned house before me has been tampering as the junction box outside is linked to a loft junction box by unmarked heavy guage bell wire rather than any form of colour coded wire! Haven't been in the outside box but that bell wire would never go in a 3m gel splice and I'm sure Mr. BT Engineer would never use chocolate block etc.

    I have -54.5v to earth at 5 in the master then strangely have -3.4v to earth at 2 (I thought this should be 0).

    Also I thought the -54.5v should go to 2 (B in a linebox)

    If it were an NTE 5 linebox am I right that A=5 (W/b or solid White) & B=2 (B/w or solid Orange)

    Have looked at 4 websites and seen 4 different versions of colours/numbers/letters and apart from the obvious 2=B/w & 5=W/b don't know what to believe.

    I know the system should work either way round but would prefer it to be right.


    Any help would be great.

    Sorry for the long post.

    Thanks

  2. #2

    Default Re: Wiring help needed please - phones

    Quote Originally Posted by gotaproblem
    Hi,
    I have my phones wired in the correct colour coding of B/w-2, W/b-5, O/w-3 (for extensions)
    ...as it should be :-)

    Quote Originally Posted by gotaproblem
    but I think the numpty who owned house before me has been tampering as the junction box outside is linked to a loft junction box by unmarked heavy guage bell wire rather than any form of colour coded wire! Haven't been in the outside box but that bell wire would never go in a 3m gel splice and I'm sure Mr. BT Engineer would never use chocolate block etc.
    Not necessarily.....
    1. You dont give any clue as to the age of your house.
    2. Your description of bell wire is too vague.

    Colour coded "dropwire" was intoduced in the Eighties as "Dropwire No9" which was about 4mm in overall diameter and had 4 wires, Orange, White, Green and Black. This was rapidly superceeded by "Dropwire No10" which has the same 4 conductors but also contains three high tensile wires (red or yellow) for added strength. Overall diameter is about 7mm.

    Prior to that, the dropwire would have been Dropwire No6 which was a figure of 8 wire about 3mm x 6mm so looks like a thick bell wire but contains copper coated steel wire. Even older is Dropwire No3 which was also figure of 8 but about 2mm x 4mm but that was discontinued in the early 70's. There are also "monster" dropwires No 4 or No 8 which have extra thick insulation for proximity to high voltage lines and trees etc.

    They WILL fit into a scotchlok type connector and there have also been connectors that looked a bit like chocolate block conectors but these were individually moulded single pair connectors that had a lid which could be clipped on.

    What you describe as "bell wire" could be an older dropwire that once fed the premises and only the dropwire from the pole to subs bracket was replaced when it went faulty hence the join at the eaves.....

    .... on the other hand, the house may previously have been occupied by a numpty, in which case, check your mains wiring very carefully

    Quote Originally Posted by gotaproblem
    I have -54.5v to earth at 5 in the master then strangely have -3.4v to earth at 2 (I thought this should be 0).

    Also I thought the -54.5v should go to 2 (B in a linebox)

    If it were an NTE 5 linebox am I right that A=5 (W/b or solid White) & B=2 (B/w or solid Orange)

    Have looked at 4 websites and seen 4 different versions of colours/numbers/letters and apart from the obvious 2=B/w & 5=W/b don't know what to believe.

    I know the system should work either way round but would prefer it to be right.
    Non of the above dropwires No3 - No8 have any form of identification so the chance of getting it the right way round is theoretically 50/50 but from experience I can tell you it is more like 100/1 against!!!

    Polarity rarely matters these days except on Earth Calling PBX lines (although I expect these are rapidly disappearing due to ISDN30).

    In a domestic/non office environment, the only times that polarity mattered was for "Shared Service Lines" long since replaced by digital carrier systems (DACS), and for some types of extensions such as Plan 105 External or Plan 107 External, again long gone.

    Dont worry about the voltage readings. The nominal voltages are

    B wire -50V
    A wire -0V

    The reason you are seeing slight difference is due to the fact that the 0V of the Phone line is referenced to Earth at the Exchange. Because your house is some distance from the exchange there is a difference in earth potential between the two buildings which is quite nomal.

    As I said, the polarity doesnt really matter so I wouldnt worry about it. I can almost guarantee that even if you put it right, at some time it will be wrong again as someone will reverse it when remaking a cable joint somewhere !

    Voice of experience speaking again :-)

    Sorry for the delay replying... been on my hols.

    Hope that helps

    Keith

  3. #3
    Automated Home Guru vex's Avatar
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    Default

    Keith,

    When you say 'someone will reverse it whenremaking a cable joint somewhere'

    Does that mean the getting the blue pair reversed should have no effect on the system?

    Is this the same for star wired system from Node Zero as lone as all the telco points at wired the same (ie all reversed or all standard) then reversing the input pairs.

    Chris
    www.intouchtech.co.uk (trade)
    NOW PART OF INVISION UK, One of the leading home technology distributors to the CI Market.

  4. #4

    Default

    Quote Originally Posted by vex
    Keith,

    When you say 'someone will reverse it whenremaking a cable joint somewhere'

    Does that mean the getting the blue pair reversed should have no effect on the system?
    Hi Chris,

    It depends WHERE the reversal is.

    If it is on the incoming line before the NTE5 then there are no problems whatsoever.

    After the NTE5 is a different story IF you have wired for a proper BT 3 wire system AND are using phones that use the Bell Wire (ORANGE/White on 3)

    The Bells/ToneCallers are wired between 3 & 5 and the ringing voltage is fed to the bell wire via a 1.8uF capacitor in the NTE5 connected between 2 and 3 http://www.diyha.co.uk/telephones/pots.html

    A reversal of the A & B wires (Blue/White pair) between any sockets will cause all phones to ring continuously and cause the line to be permanently off hook. (Proper bells will not ring continously but will give a quick "dink" as the bell armature is permanently attracted to the pole face of the bell coils)

    The reason that this happens is that the properly wired phone socket has a bell across 3 & 5. The reversed socket also has a bell across 3 & 5 but this is actually 3 & 2 because of the reversal and puts the two bells in series across the line.

    Quote Originally Posted by vex
    Is this the same for star wired system from Node Zero as lone as all the telco points at wired the same (ie all reversed or all standard) then reversing the input pairs.
    Chris
    It should be...I think!

    Are you saying that you have an installation where pairs are reversed between patch panel and sockets?

    At the end of the day, the actual COLOUR of the wire is irrelevant.

    What is important is that the same numbered terminal is connected together and if two wires are supposed to be from the same pair then they should be run using a proper pair be it Blue, Orange, Green or Brown etc

    Hope that helps

    Keith

  5. #5
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    Default Re: Wiring help needed please - phones

    Keith,

    Thanks for the detailed reply.

    The property was built late 1970's so it could be the remnants of an earlier drop wire.

    I only started looking into it all because I'm getting ADSL dropouts at night usually between 11pm and 7am. The rest of the time I have no probs. I don't have economy 7 so nothing switching at night and none of the phone wires at any point come into contact with any electric wires.

    I assumed it must be an exchange problem and reported it to my ISP then got a call from BT wholesale to say there was an anomoly on my line. Thought I'd have a good look around before they came to save a callout bill if it was something I could be held responsible for and charged.

    Thanks again

    Al

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