I've severed a wire (Alarm), and don't know how to fix it...

[maf20]

I've been a right muppet and severed one of the wires which leads from a room sensor to the alarm box. When I did it last night all hell broke loose and the full house alarm was going off for about half an hour at 10pm!

I've never worked with alarms in the past.

I've noticed that the wiring doesn't look like normal electrical wiring and looks more like telephone wire.

1. Am I going to be able to fix this myself?
2. If I can is it a case of chopping out the severd wire and connecting the two bits together somehow?
3. Or will the hole wire need replacing between the sensor and the alarm box?

By the way, the alarm is a EUROSEC

Cheers guys

 

[josh1e]

I am not an expert but have some limitied experience with alarm systems, so follow my advice at your own risk

if you have simply chopped the wire then both ends that are now flapping around in that hole should have matching colours.

There is a likelyhood that the wires themselves are carrying 12v dc, so be careful not to touch them together.

method 1 - proper way to do it (imo)

with everything turned off & the battery backups removed, tape a new wire to the one u have cut, leave it on the roll & then goto the alarm panel & try pulling it back, it should run the new cable for u if there are no obstructions. once u get it there, goto the other end, estimate how much you need from the hole to the pir sensor, add a meter or two extra & then cut the roll & tape that end to the other cut piece & pull through from the sensor, when you remove the wires from the sensor, write them down & replace exactly as you found them, repeat this at the alarm panel.

method 2 - usually quick repair, if done properly is usually adequate, good if you cannot easily run new cable

turn off the alarm system & remove any fuse from the spur, unplug it, and remove the battery backup either from the alarm panel or bell box or both.

carefully peel back the outer sheath, usually white, this will reveal several cores, all different colours. do this on both sides of the break.

personally i would solder each core together not forgetting to tin the wires properly first. once u have soldered them, then use heat shrink sleeving and a hot air gun / lighter to shrink the sleeving.

if you cannot do it like this then i would recommend a waterproof junction box and taking both ends & twisting them together, then put the pair into the junction block so both screws clamp the twisted pair.

once you have done this check again you have the correct colours matched up. just give it another check before you turn the power on. dont reconnect the batteries again immediately, ensure it all works properly first before reconnecting them last.

the alarm probably sounded because each pir, alarm panel, keypad & bell box have tamper switches, which are normally closed. if u cut the cable then the alarm is telling you someone has opened the housing or tampered with it. Its actually a good sign because alot of the alarms we repair / upgrade have not had this circuit connected.

lastly when you test it, remember if any of the housings are open or something moves in front of a pir sensor, window / door open it will trigger the alarm, i know this sounds daft but the number of times i've watched an apprentice scratch his head because the alarm keeps sounding while he's got the alarm panel open with the protected front door wide open & a dog wandering around in front of the pir

hope this helps & good luck

 

[maf20]

Thanks for the advice. Doesn't sound too easy mind, I'll give it a crack.

I think I understand most of what you have said. Is there any way of connecting the wires back up without soldering them. Say using a junction box (or whatever they're called) and lining up each wire that way?

I'm quite handy around the house, but on electrics I'm clueless.

Does anyone have any idea how much a professional might charge for something like this? Not after a quote but if this is the line I go down I don't want to have my eyes ripped out!

Thanks again

 

[breezer]

Changing the cable is the best way, how ever its not always the easiest.

You can join the cable, but you dont need water proof junction boxes.

you can use these

BUT since you have sliced the cable chances are there is not enough slack to join both ends together so you will need 2 junction boxes, and more cable. you cant easily hide 2 junction boxes.

I would opt to solder i since its a better joint, yes you may need to solder in two places (all 6 or 8 cores) but when done it will be easier to hide.

you can also use choc block or crimps, but you still have to hide them and soldered joints are smaller in size.

You do join them colour to colour, no need to downpower the panel / pull mains thats a BAD thing to do anyway. Chances are when you severed the cable you took out a fuse, so join the cable in your chosen method, then replace the fuse.

you will probably then have to clear the tamper with your code.

as for how much would an alarm engineer charge to do what i have written, no idea what so ever,

see

View media item 2443

 

[josh1e]

Hi maf / breezer

breezer, please correct me if i am wrong, as my experience is limited in alarms, although i thought :-

if your using a gas powered soldering iron then no need to power down (imo) although electric soldering irons can be a problem if there is still current in the wires your soldering.

I agree for most "end users" it could be bad to turn the alarm off, as if it was installed for you & you dont have the engineer codes or a good understanding of how to reset it & re-arm it, then you could be left without it working. however if you solder a live 12v cable which is connected to a live circuit board inside the alarm panel, you could also do damage to the board.

if u just want it up & running quickly then junction boxes will do the job, they work 90% of the time fine, i wouldn't say they were a "good" connection though. If anyone ever moves the pir & the cable gets pulled they're likely to break the connection as it wouldnt be obvious that the cable was joined with junction boxes & you may forget where u put them if there behind a wall. a new cable run or solder joint is what i believe most engineers would do in this situation.

also some alarms work on voltage drop sensing & solder joints are alot less problematic with alarms which are prone to false alarms.

 

[maf20]

Thanks again for the help and advice guys, much appreciated.

I've just stripped back the core and there are 6 wires inside of it (red, green, black, white, yellow & blue). All have been cut except the red one. It looks pretty easy to solder them I agree. Thing is, how do I make sure that the solder on each wire doesn't touch with another solder from another connection and short? Is it a case of insulation tape around each soldered joint?

Forgive me as I say but electrics is way off my radar.

Thanks again

 

[josh1e]

Hi maf,

try something like this http://www.hilltop-products.co.uk/product.asp?ID=13

its usually available from any diy store / electrical retailer. cut a length 2-3 times longer than you think u need. slide it over one side of the cut core. then make your solder joint. as the core heats up, usually some of the sleeving is affected by the heat & you end up with a longer piece of exposed cable than you started with (thats why you cut the tubing longer)

now slide the tubing over your exposed wire & heat up until it is stuck in place & check to make sure there are no exposed sections of wire.

move onto the next wire & repeat. once you are finished you could tape them all up neatly with electrical tape, but must be certain that the heatshrink sleeving has covered all exposed areas, or you will get a short as soon as you tuck them all back into the wall...

good luck mate, its not too hard, just alot of patience

 

[maf20]

Cheers Josh, very helpful thank you.

Does the tubing need to be shrunk on with a flame gun or will a hairdryer suffice? Didn't want to fork out for a flame gun if I didn't have to.

Thanks again

 

[josh1e]

Hi maf,

no problem, i've had alot of help on this forum, so its nice to be able to help someone else

the tubing doesnt need alot of heat, although has a certain temp where it will go limp & then start tightening up / shrinking. if u dont reach this temperature, nothing will happen & it will just slide up & down ur cable, not protecting anything.

a hairdryer should suffice, if it has a hot heat setting. i would suggest u practise on a length first to see what will happen. remember not to hold it in your hand when u try lol....

some people use paint stripping hot air guns, although i would be very careful with one of those if u try it. There are also pocket gas torches which can do this sort of thing. when u shrink the tubing, let it cool & try pulling on it, to slide it up & down the cable. it shouldnt move at all. if it does, either you have the wrong size tubing or havent shrunk it enough.

oh & remember your solder joints will need to be reasonably tidy, or the sleeving wont slide over it

you should be shrinking it over both the exposed core you soldered and a reasonable amount of the coloured sleeving to ensure if it flexes / bends there will be no exposed areas.

regards
josh1e

 

[breezer]

insulaion tape is fine.

heat shrink would be better but then there is the problem of using a 240v appliance on site, that, and the expese (oh and hassle of running extension lead) is a reason why no one uses them.
___________________________________

Similarly for mains soldering irons. also unless its an instant heat soldering gun (i still have one) the time it takes for mains soldering iron to heat up you could have done it with gas.

Yes an earth fault is not a good idea on a live cct. but for the time its going to be there, no problem.

also burglar alarms are not voltage drop sensing, two wire, car alarms are.
That said a burglar alarm detector will go open cct at 10.5v but bad joints can cause voltage drop and high resistance, both of which cause false alarms.
Some "modern panels will even "complain" if they detect high resistance.

you should never down power a panel unless you really have to, soldering a cable is not such a reason.

The problem arises when you down power it, and the SAB starts, its most anoying, specaily when people say "did you know the alarm is ringing?"

or if its signaling system and it has red care and you didnt check, you are liable to get a few phone calls

and the worst has to be if the panel crashes.

so no, i do not recomend you ever down power a panel unless you are upgrading it

 

[josh1e]

breezer,

thanks for the clarification on red care etc mate, i hadnt considered that tbh....

when the op said he was unfamiliar with electrics, i assumed certain things in my reply, like he maybe unfamiliar with soldering, may take more time to make / re-make the connections to get them right & to get the joints to fit under the sleeving, that the fuse may not have tripped (alarm was sounding) and that it was likely his own alarm as he said it was going off around 10pm (unlikely to be working on site & unlikely to have a dialler)

i realise these were only assumptions & will try to be more thoughtful in future replies

I was concerned he may do more damage to the panel in trying to correct it while it was live.

thanks

 

[breezer]

its not a problem, you did raise fair comment.

 

[maf20]

Thanks again guys.

Bought all the kit and going to try and do it tonight...but not power the alarm back up until tomorro for obvious reasons.

Just one thing, and again excuse my electrical ignorance, if I am shrinking the sheath over the wire does it still need to be soldered or can it be intertwined together with the other end?

Last question this, and then I'm going to do it....when X factor is on!!!

 

[josh1e]

i'm getting the impression u really dont like soldering lol


i think you really need to solder it or use junction blocks on a repair. there are different considerations to the repair your doing, the integrity of the connection and the protection against short circuit.

the sleeving is solely designed to act as short circuit protection, not hold the connection together. the connection could be loose inside the sleeving or come apart if anyone ever moved the sensor or alarm panel.

on any repair like this i would solder it. I would then be happy in the knowledge the connection itself wasnt going to break. (solder is usually stronger than the cable your soldering too

without a proper connection being made prior to insulating it, the wire wont stand up to any minor abuse like being shoved back in the hole, let alone the wire being pulled with any force.

x-factor = why the swedes have assisted suicide

 

[breezer]

maf20, you must solder or connector block or junction box it. if you dont you will get false alarms