Wiring BT sockets with non solid core wire?

[Rafal]

Hi

Is it ok to wire domestic bt sockets with multistrand /alarm/ cable? What is the reason for bt to use solid core?

Rafal

[Andy Hall]

They may have some other policy as well, but some of the practical reasons are that solid core wire is used for premises wiring because it stays reasonably in position, and because the punch down connectors need to use solid core.

If you have outlets with screw terminals then you could use either.

.andy

To email, substitute .nospam with .gl

[Set Square]

There are 2 issues here!

Proper telephone cable uses twisted pairs - that is pairs of conductors which are twisted together along their length in order to minimise any induced interference. I'm not sure that alarm cable does use twisted pairs. If it doesn't, you definitely shouldn't use it for phone circuits.

The second issue is that all BT wiring uses IDC push-down terminals - where the cable is forced into a small slot in a metal plate. This only works with solid core cable. If you use extension sockets with screw terminals - as sold by some of the sheds - this is less of an issue.

When you consider that phone cable is cheap - e.g. Screwfix do 100 metres for just over 6 quid - it really isn't worth not using the proper stuff.

[Dave Liquorice]

Alarm cable does not come in twisted pairs it's just a number of wires. The twist is not essential but you may get problems with induced noise/hum without it.

Fits the IDC connectors properly. Stranded may work but over time I wouldn't like to say that the blades won't sever the strands and cause an intermittent problem or just a failure.

CW1308 is dirt cheap:

RS 2 pair =A314.28 3 pair =A316.49

TLC 2 pair =A37.99 3 Pair =A39.60

All + VAT and for 100m white. Personally I'd use 3 pair but you don't need to.

[mike ring]

"Rafal" wrote in news:c72da0$hf7fe$1@ID-

25835.news.uni-berlin.de:

The standard wiring method these days is solderless insulation displacement connection (IDC)

This method is instant and reliable, but does not work well on stranded wire.

More generally, single core cable is preferred except for flex, ie on the installed side of fittings. (unless the cable is so heavy as to be unworkable with single core)

Standard disclaimer .... At least thaat was the answer when I were a lad

mike

[Colin Wilson]

I did mine in alarm cable about 8 years ago and never had a problem

[Andrew Gabriel]

If anyone wants the bulk of a drum of 20 pair CW1308 (probably around

75m, but I'm not unrolling it all to measure it;-), let me know.

[Dave Liquorice]

Naw, I've still got some lurking in the back of the garage somewhere.

[Rafal]

Thanks

[Dave Plowman]

For the insulation piercing terminals found on most sockets - stranded cable won't make a reliable connection. Of course I've seen sockets with screw terminals, but they're not so common.

Also, alarm cable doesn't comprise of twisted pairs - just how much difference this would make in practice I don't know. But telephone cable is so cheap it's not worth finding out...

[BillV]

The twisted pair aspect could be more important if ADSL was used on the line...

[Dave Plowman]

I've just got ADSL. I was concerned it wouldn't work properly as my internal telephone wiring goes to every room and has been much modified over the years - and picks up some lighting dimmer buzz which really stuffs the ordinary modem. But ASDL works just fine - and the computer outlet is the very last socket in the chain.;-) Still, I'm going to do the job properly with the router sited at the incoming line and Cat5 run to both the computers - at long last I'll also be able to get them to talk to one another.

[derek]

I used about 10 feet of existing alarm cable when we extended the phone into the living room. It worked fine 'till we got a second line for the fax and ran it down the same cable. We got quite troublesome over hearing between the two circuits. Eventually we got rid of the fax and used a dect phone plugged directly into the master socket for what was now a second voice line, problem solved.

So when we got DSL I had an electrician pull Cat 5 from the master socket to the computer. However, I couldn't get hold of any faceplates at the time and impatience got the better of me so I plugged my microfilter into an extension cabled with alarm wire and the ADSL modem synced up within one second.

The Cat 5 is still unused 2 years later.

DG

[Ian Stirling]

If you'r on the limit of being able to get ADSL, then the extra loss may make the difference to the modem syncing or not.

If you'r close to the exchange, it probably makes no difference at all.

[Dave Plowman]

Less than 1/2 a mile as the crow flies, I'd say.

[Lurch]

On 2 May 2004 17:32:29 GMT, in uk.d-i-y [e-mail] (Andrew Gabriel) strung together this:

Any money involved?

[Christian McArdle]

Then I always use Cat5+ UTP for phone lines...

Christian.

[Woody]

Surprisingly, probably due to capacitance, alarm cable has a significant effect on the audio quality - it seems to apply noticable higher frequency roll-off.

[Dave Plowman]

I'd be utterly amazed if this was the case over the sort of distances found in any house.