main earth to house through a BT circuit.

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hamlettphil

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got a phone call last night, from a mate of mine. his mums house does not appear to have a Main earth, on the suppliers side, dont know the type of system it is or anyhting else. she has contacted the supplier and they said thet will run the earth through there BT circuit ( wot the f*^k) i have never ever heard of this before, dont konw if it got mixed up or what, has any one else heard this weird theory before???

 
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That`s a new one on me mate - AFAIK that cannot be done. :eek: :O

There`re only 3 choices:

1) supplier provides earth via lead sheath of incoming cable (TN-S) :)

2) supplier provides earth via PEN (combined neutral+earth) (TN-C-S) :)

3) supplier does not provide earth - customer supplies via earth rod, tapes, structural metalwork etc. (TT) :)

There are no other options. Your BT cable cannot carry fault current:_| - it simply isn`t big enough. Methinks someone has their wires crossed. :p :^O

I hope? :| ?:|

 

hamlettphil

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me thinks that 2, just thought id put it out there. well im staying well away!!!

 
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Yeah. You wouldn`t want to answer the `phone in THAT house, would you now.

Mrs. KME thinks it may be a new "fault early warning system" - If you`ve an earth fault, the phone rings "backwards or something":^O:^O:^O:^O

Thought that`d tickle your fancy, ADMIN:O:x

 

Mr Sworld

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Ok, a phone line can get 50V on it when ringing....... However using it as an earth!

OMG! :eek:

 

ABC Technical

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Ok, a phone line can get 50V on it when ringing....... However using it as an earth!OMG! :eek:
Indeed it can, I got a belt of an old style BT box (Remember when they still had books & took 2p pieces?) I was soaking wet, it was hammering it down & the "Box" leaked like a sieve.

I tried to phone my dad to come & pick me up, ended up walking home soaking wet & with cuts all up my fist where I'd punched the crap outta it for belting me. Oh the memories of a mispent youth *SNIFF* Brings a tear to the eye it does. :^O

 

Admin1

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Talking to my Brother-In-Laws Father, Last Night.

He said years ago, (I can't remember if it was him or his friend) got a belt off of one years ago (BT 8 wire).

He said that there was only one wire that gave a belter if you were touching it the same time as an incoming call coming through.

He also said that he measured it as 100 V.

 

ABC Technical

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Talking to my Brother-In-Laws Father, Last Night.He said years ago, (I can't remember if it was him or his friend) got a belt off of one years ago (BT 8 wire).

He said that there was only one wire that gave a belter if you were touching it the same time as an incoming call coming through.

He also said that he measured it as 100 V.
:eek: 100V. No wonder I jumped. :^O

 

lcdman

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When "The Post Office" used to supply a ring voltage it was 50V DC nominal from a regulated supply or storage batteries at the exchange, to power a ringing bell circuit and came in on the "3rd wire" (or pin 3 of the standard 6 pin IDE connection, 2 & 5 being those for the telephony).

Not used that much now as most telephone devices don't need this ring voltage, they create ringing themselves, and if you take the front off your NTE5 master socket you will find only 2 wires connected.

 
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When "The Post Office" used to supply a ring voltage it was 50V DC nominal from a regulated supply or storage batteries at the exchange, to power a ringing bell circuit and came in on the "3rd wire" (or pin 3 of the standard 6 pin IDE connection, 2 & 5 being those for the telephony). Not used that much now as most telephone devices don't need this ring voltage, they create ringing themselves, and if you take the front off your NTE5 master socket you will find only 2 wires connected.
3rd wire?????? ?:|

telephone circuits have been 2 wires for donkeys years....

the internal wiring of the bell circuit inside the old type telephone created a "third connection (wired)" inside the phone..

To wire two or phones in parallel you used to have to modify the internal wiring of the phones to stop the "Back tinkle" when one telephone was dialling a number and could cause the parallel phone to sound as though it was ringing!

With modern LJU's the bell capacitor is inside the master socket, and

the third wire has to be continued through to all of the secondary sockets is so that any old-type phone can still get the ring current via the bell capacitor which is connected between pins 2 & 3 on the LJU.

The ring appears to only be on the one wire.. because the other one is with respect to earth at the exchange..

The earth reference was also exploited in the old days with the Party line system..

where two houses had a telephone each over the 2-wire circuit sharing a common earth return.

(bit like stereo headphone L-R & common return.)

But both phones could not be used simultaniously....

here endeth todays telephony history lesson..

next time we meet class can you bring your homework in.

remember we needed pictures of the uglyest telephone you can find..

and a handwritten copy of all entries under letters J-K from your local phone directory:O:^O:^O:^OGuiness Drink

 
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