just found this site,brilliant! can one of you experts please tell me why not to use bt type cable(solid core) as opposed to multi strand? ta! are there actually any service affecting negatives using the solid core?

I have seen a fair few older systems wired with BT single strand (probably ex BT staff with a garage full ), its quite brittle , harder to strip , and IIRC can't cope with high sounder currents.Horses for coarses , as they say.

We'll have to wait to see what the experts say.....

From a physical point of view I agree with the last statement: the cable is very hard to strip because the coating is a special PTFE that stretches, rather than breaking like the covering on stranded cable.

BT solid-core cable was designed to be used with terminations called "IDC", which is short for Insulation Displacement Connector. You push the wire (covering and all), down into the centre of a "V" shaped receptical. The bottom of the "V" is the exact diameter of the internal solid core. As you push the wire down (with a tool called a Krone Tool), the insulation pushes away (displaces), and a good connection is made . . kind of like a very basic crimp. It is a quick and easy termination method (I should know, having installed a telephone system in the past with over 8000 connections, in a previous job).

If you use solid-core cable on other systems (stripping with pliers or cutters), you come across two physical hurdles: 1-The cable is difficult to strip and you end up with stretched insulation that can look horrendous, and takes longer to prepare before termination. 2-You can nick the solid-core very easily with your cutters and after only a few flexes of the end, it can break. It can be a very unstable connection medium.

From an electrical point of view a solid-core cable can induct more noise, than stranded cable. Remembering that cable runs can act as aerials for electrical noise if not properly terminated, solid-core is more prone to conductivity of unwanted signals.

Hope this explains.

Regards,

Gimmick.

been away for a while so sorry about delay in saying thanks for your replies,much appreciated.one other question,what are wireless systems like?if you HAD TO which would you have in your house,wireless or solid core fed ? (the reason i'm asking is 'cos i've run solid core throughout the ground floor with no way of changing it now,should have found this site sooner!!!!!!!!!!!)

Id rather use Telephone cable than wireless, hardwired equipment is cheaper as well.

I will gladly third that opinion

In Zimbabwe we used solid core cable for everything - and the cable never caused us a problem - just be careful with it thats all.

Go hardwired.

Stranded alarm core cable and telephone standard cable is very diffrent. The solid copper in a telecom cable is twisted in a spechial way to reduce noise and to be able to take the loads of on hook and of hook. Also this cable has a rating of 200 vdc and 100v ac as some services carry difrent voltages eg Normal PSTN 54vDC with a ring voltage of 95vAC ISDN 95vdc and Spechial circuits known in are industry as private wire PW carry diffrent voltages from 50vdc to 190vdc also some other equipment carry this range of voltages all circuits have amparage of 500ma. As for alarm cable it has no spechial twist other than the standard shield effect. and is also limted to 100vdc. It is quite common to go in a new house and find that they have prewired the customers extension with alarm wire. Its a blody pain because if you connect it to ISDN or use it for DSL the noise ratio is unusable. thats my two pittance

BT engineer mode

Granted - the two wire types have different characteristics - and I can appreciate that using alarm cable could pose a problem for a telephone system, but I can't see the telephone cable causing a problem for an alarm system (well, not for the same reasons anyway).

No your right but ime sure that to be compliant with IEE regs i do believe that strandad alarm cable should be used but i may be wrong :!: