How do you check the alarm cable cores ?

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Hi

The section of 6 core alarm cable which was fitted to run to the external sounder has been outside now for some time. The end has been taped up with insulating tape.

When I went up to have a look at it I found that it had been blowing about in the wind and over time the external sheath had worn away and one of the internal cores was worn through as well.

I may be able to cut the damaged section out, but I am not sure.

I can not replace the cable, but I would like to test it to give me piece of mind. What would be the best way to test the insulation between the cores without damaging it. I understand that the cores are rated to 60AV ac.

Any help would be much appreciated.
 
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When testing for breaks in the cores in alarm cable (6 core) I have always cut back the ends slightly and spliced the cable together at one end in pairs and then got my multimeter on the other end on continuity mode and tested each core to each other core in turn. In this test each core should only respond to one other core.

I suppose you could use the same principle to test for integrity, attach a 12v SLA to one of the cores at one end, test all the cores at the other end with a multimeter on voltage mode and only 1 core should show voltage. Move the SLA battery onto the next core, rinse and repeat until you have tested all cores. In each test only the core you attached the battery to should show any significant voltage, you may of course see leakage in the mv range.

Someone else may suggest a better alternative but if not this method will not take up much of your time even on cable with more than 6 cores.
 
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DO NOT USE A SLA BATTERY to conduct tests om alarm cables as the current output of aSLA battery can be very very high, and if you have a short in the cores of you cable IT WILL FRY THEM and possibly CATCH FIRE!!!!!!

use a 6 volt (lantern battery)and a 6 volt bulb (lamp) if you dont have a meter

DO NOT USE A SLA BATTERY!!!!!!

Oasis
 
DO NOT USE A SLA BATTERY to conduct tests om alarm cables as the current output of aSLA battery can be very very high, and if you have a short in the cores of you cable IT WILL FRY THEM and possibly CATCH FIRE!!!!!!

use a 6 volt (lantern battery)and a 6 volt bulb (lamp) if you dont have a meter

DO NOT USE A SLA BATTERY!!!!!!

Oasis

A 6v lantern is what, 1100mah so it is probably just as likely to burn out a shorted cable as a 12v 1200mah SLA. Although yes the SLA would probably be more damaging the maximum current drawn on a line by a domestic burglar alarm is normally going be around 250mA so either battery is in excess. If you have tested the pairs for continuity the battery test for integrity is belts and braces really anyway. I'm just saying.
 
ok then.

just you sit there with a 1.2 or a 2.1 amp hour battery and a small bit of alarm cable.
then short it accross athe + and - on the SLA, but watch your fingers

then do teh same with a lantern battery,

and post the results.

for a hobby i build switch mode and standard charger systems for SLA Lead acid Plante cells up to 230 vdc via sine wave inverters, triac based systems as well
one thing that i am also proficiant in is loadings and capacity on battery systems

so when i say DONT USE A SLA battery for testing perposes i am not just blowing wind!!

carry out what i have said, but beware you will be in for a shock

Oasis
 
ok then.

just you sit there with a 1.2 or a 2.1 amp hour battery and a small bit of alarm cable.
then short it accross athe + and - on the SLA, but watch your fingers

then do teh same with a lantern battery,

and post the results.

for a hobby i build switch mode and standard charger systems for SLA Lead acid Plante cells up to 230 vdc via sine wave inverters, triac based systems as well
one thing that i am also proficiant in is loadings and capacity on battery systems

so when i say DONT USE A SLA battery for testing perposes i am not just blowing wind!!

carry out what i have said, but beware you will be in for a shock

Oasis

I wasn't saying you are wrong mate and I'm open to suggestions I just didn't think it would make a huge difference but if you say it will then I will take what you say on board. I wasn't trying to put the cat amongst the pigeons I was just trying to answer the chap's question from my own humble experience.
 
the maximum current drawn on a line by a domestic burglar alarm is normally going be around 250mA .

That because the circuit involved is battery positive, wire, RESISTANCE of items, wire back to panel, battery negative.

Current = voltage divided by resistance.

If resistance is zero then current is infinitely large. Resistance in battery and wire limits it bit. latern cell has a high internal resistance, lead acid battery has a very low internal resistance.
 

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