House alarm system questions

[Postman]

Morning to all.
I hope this is in the right place so here goes. I have a alarm system fitted by ADT........Their alarm system was put into 4 different places, 3 house and 2 business sites. and would like to here from some people out there about a problem we have. On 3 occasions now, we have been burgled into without the alarm going off or burglers getting to the alarm panel, cutting the wires and the antenna and cleaning out the shops.
I am an electronic service technician and fail to see how this can be done. Does anyone know how they get it right to pass the sensors???????????? As per ADT we get the old " I dont know".....and keep on paying. Any help out there would really be appreciated, please pm me or e-mail me.
Thanks

 

[BrownOut]

Wow! That's surprising. I'd fire ADT.

 

[jakeselectronics]

Someone is either really lucky with numbers and should go buy a lotto ticket.
or someone who knows the system inside out and knows how to disarm it,
or an inside job.

Its weird and uncommon for an alarm system not to go off.
Maybe request the main panel be moved somewhere inacessable or to a locked cupboard.

 

[Dean Huster]

Most alarm systems are set up such that they want to see a set resistance (say, 4700 ohms) in a good, secure circuit. Opening (infinity) or shorting (zero) the wires leading to the sense device (whether a switch, motion detector, fire sensor, etc.) should set the alarm off.

 

[audioguru]

ADT is an alarm company that installs their system for free if you sign up for paying them a fortune to "monitor" it. They monitor it when it is triggered then it dials up the operators at its headquarters.

It is a scam. They collect lots of money each month.

Duh! The dialer is useless when the telephone line is cut by the burglar.

 

[BrownOut]

Most alarm systems are set up such that they want to see a set resistance (say, 4700 ohms) in a good, secure circuit. Opening (infinity) or shorting (zero) the wires leading to the sense device (whether a switch, motion detector, fire sensor, etc.) should set the alarm off.

That's not exactly 21st century. I have a simple PIR detector set up at my house. It never fails to detect when someone walks up my driveway.

 

[tunedwolf]

Once, I could agree with it being luck...maybe hit the right code, cut/ splice the right wires etc, but I doubt it.
All wiring carries anti-tamper circuits, any decent alarm engineer will rotate wiring colours throughout the installation, so it's pretty unlikely that the same wiring colours were used twice in a row.

If this is a monitored system, I would want to see a copy of the alarm centre logs for the evening. I would also be calling in a local alarm engineer to rewire and thoroughly test the entire system, and not ADT.
Incidentally, the Alarm centre will have flagged a telephone line being cut, although they will not know the reason for it.

It has been suggested already that an insider with intimate knowledge may be responsible. I doubt that is the case. Much more likely the cause lies with bad site planning and installation or poor or faulty equipment. ADT on the third occurence would be paying for re-stocking my shop or my business would be going to another company.

In any case, you would be advised to put in place additional measures to contain any break-in to one area if possible. By this I mean physical security. Make it very difficult to move around, and impossible to go from one area to another without passing at least two methods of tripping the alarm.

rgds

 

[jakeselectronics]

cutting the wires and the antenna

How new is the system?
Whats the antena for? Does it use the mobile network to communicate?

 

[kchriste]

What types of sensors do you have? Some are pretty easy to fool; like PIR sensors by wearing a heavy jacket, hat, and ski pants, which are at room temperature, and moving slowly past the PIR while keeping your face hidden.

or someone who knows the system inside out and knows how to disarm it,

Practically all systems have a master code. A regular user's code is logged so you can tell if it was accessed by them and when.

 

[audioguru]

Incidentally, the Alarm centre will have flagged a telephone line being cut

How?
If it is a normal land telephone line then it does nothing when it is cut.
I don't think it calls the Alarm Center periodically to say it is still alive because then it would interfere with the homeowner's only telephone line.
I don't think it uses its own expensive telephone line.