6 core alarm wire

[sophie]

i am new to diy so am completely clueless. please forgive my ignorance! yesterday i cut through an alarm wire which goes to an unused (or not working) door sensor. i didnt think it would do much as the sensor doesnt work. after that the alarm wouldnt work (although cutting it didnt cause the alarm to sound so it cant have been tamper proof) so i reconnected the 6 wires. i want to extend the cable so that i can fit it under the carpet (i cut it because its ugly and wanted to get rid of it - covered in paint etc). i bought some 6 core cable thinking it would be easy to extend it but the colours are all different!! how do i know which colour to attach where, or perhaps it wont matter as long as it is the same at both ends of the 'extension'.

thanks in advance

sophie

[ABC]

As long as you have the same colour at both ends of the extension it should be OK. Ideally it would be best to replace the whole cable run, if it's possible as joints could cause false positives.

[T i m]

I'm not sure what yer soldering skills are like but if you *have* to extend (rather than replace as suggested) the 'best' way to join the wires so as to avoid issues in the future would be to lay the two ends side-by-side (and maybe tape them together), strip maybe 10mm of insulaton off each of the wires then twist together each of you chosen mating colours. Give each pair a nice solder then insulate each 'twig' with some suitably sized heat shrink tubing, then a couple of turns of PVC tape over the lot. You can then loose the connection under the carpet / whatever knowing it should never give you any trouble with false alarms etc. ;-)

All the best ..

T i m

p.s. A fancier way would be to do the joint 'in-line' (rather than side-by-side) but that isn't so easy for a novice.

[Sparks]

When you say the alarm doesn't work, what do you men, it won't set, or it is just totally dead? (what make and model is it?)

You may have blown a fuse in the panel, even if the sensor does not rquire power (as most door sensors don't), the installer may have still shoved power down there. Do you have some PIR movment detectors in the house - if so, does thier little red light still activate when you walk past them? (assuming they did this before!) If they don't (and they did) then you have probably popped a fuse when you cut the wires

Exactly, the signals won't care, or even know, if they start off in a red wire, change to a yellow one, then go back to a red one again!

It is unusal that the colours are "all different" unless you have bought the wrong type, or have the wrong type installed already! What colours are the wires in the cable you have bought, and what are they in the exisiting run?

Alarm cable is usually made up of solidly coloured, multi-stranded wires (Each wire will be made up of a load of very thin wires). Telephone cable is made up of pairs of wires, one wire in a pair being a solid colour, usually with white stripes (but not always), the other wire in that pair being white with stripes the same colour as the other wire in that pair, this type of cable is solid core (one fat strand per wire)

Sparks...

[Broadback]

Also if you have blow a fuse then when you replace it you may have an alarm. It is possible that even if not going to a sensor then 2 wires are used for tamper, that is to say the alarm expects them to be joined, this is so that if some clever clogs cut a cable trying to disable the alarm it goes off anyway. Also is it possible that some of the wires are being used to supply something else, say the bell?

[Dave Plowman (News)]

6 core is used for powered sensors like PIRs. Or at least was. ;-)