Alarm cable pressed almost flat by floorboard

[kazgaz]

hi guys

I've been having some very intermittent faults with my Accenta G4 (previously discussed on here) & I found one of my alarm cables has been pressed near flat by a badly refitted floorboard. It goes to the hall PIR. The system has been working ok for the last 3 weeks or so, but the fault is very sporadic.

I'm obviously going to cut out the damaged part of the cable and solder back to create a sound joint. Whole cable replacement is near impossible as it's buried in plasterwork by the control panel.

What sort of faults can you get with a flattened cable?

Cheers!

 

[Handymanjo]

Have the faults always been on the hallway zone ?
Have you had any tamper faults ?
If you have a multimeter i would check the resistance of each core within the cable .The cable will need to be disconnected from the panel and hallway sensor to check.if the cable is ok then the readings for each core should be nearly the same reading.if you have different readings between the cores then cable could be damaged.
Also check for a/c voltage on alarm that could cause intermittent false alarm if high a/c reading.you could fit filter for the a/c

 

[kazgaz]

Hi handymanjo

Fault has always been a blown F2 fuse on control panel, taking out the 12v supply for the PIRs. I've systematically been disconnecting each PIR to see if I can identify where the fault is originating from. I'm now down to my last 2 PIRs, hall and living room. It's been ok for around the last 3 weeks so far, but I've had that in the past as well.

I'm still going to replace the control panel for an Elite 48 as the Honeywell panels quality has apparently deteriorated since moving manufacturing to China. Before I change the panel tho I'd really like to pin point where the fault is originating from if I can.

I'll have to dig out my multimeter! What's the correct process for checking each cable core, in layman's terms!

 

[Handymanjo]

Sounds like possible short on power cable?
Meter cables out first
Change power pair on hallway detector for different colours and see if fuse problem goes away?
This could cause other faults if cable is damaged ? Tamper fault/zone activations

 

[Handymanjo]

Check cable
Disconnect cable in panel and detector
Twist together pairs at one end.
Red/black
Yellow/green
White/blue
Take resistance reading in ohms between each pair and record readinging
If ok readings should be almost the same reading
Now twist all cores together at one end and take reading on all pairs
Hold meter on single core eg white and the take reading between white and each other core seperately
Do this for each wire and check readings
This way you have checked pairs and each core in the cable
If readings are almost the same you my need to start looking else where?
Possible faulty detector?