Monitor Off-line cables to detect cutting!
One of the biggest challenges in the fight against cable theft is the protection of cables that are not powered. One great example of this is in agricultural irrigation equipment, where a pump can often be at the end of a considerable cable run. When the pump is not running, the cable is often stolen, with expensive results.
The Cable Theft Monitor (CTM) module allows you to monitor “live” or “dead” cables and provides a contact output to signal when anything goes wrong. It can easily be connected to our GSM Commander product (or any other device) to notify you remotely of any event on the cable. It is able to monitor both 3phase and single phase cable runs.
Product Highlights
- Fully potted, rugged unit.
- Rising-clamp pluggable screw terminals
- Monitors 3phase and single phase cables.
- Contact Output to signal fault
- Contact remains closed as long as fault is present
- Operates from 12V
- Includes 50W DC reflector.
How does it work?
The CTM injects a special DC signal into the cable, and verifies that it is reflected at the far end of the cable. If the signal is not reflected, the CTM will detect this and activate the output contacts. The contacts will remain closed for as long as the fault condition exists.
Application Areas
There are two main application areas:
A: DC loads (Motors, pumps and heater elements – as in picture above)
B: AC loads (Street lighting, commercial, residential)
In the case of DC loads, the load itself reflects the signal. In the case of AC loads, one must fit a DC-reflective device at the far end of the cable, which will allow the signal to be properly reflected back to the CTM.
Dealing with multiple loads..
If there are multiple loads on a line, and they are some distance, a single CTM will be unable to monitor the cable running between the first and second loads. To monitor this “far side” cable, we fit a second CTM unit on this line, but after a power fail isolator. The isolator will disconnect the cable if there is a power failure, allowing the CTM units to each operate on its own piece of cable and thus providing you with more specific information over where exactly the cable has been cut.
Dealing with long cable runs
If there is a long cable run (more than a few kilometers), you would ideally want to know whereabouts the problem is. It is of no use to be informed that there was a problem between point A and B if A and B are 50km apart. The solution is to add points X,Y and Z (or more) in-between points A and B. At each point, there will be an isolator that disconnects the line if there is a power failure. This allows the piece of cable from A to B to be isolated into 4 separate lines, each of which can be monitored by a CTM device. The figure below illustrates this. At the end of each line, you will notice the DC reflector device, allowing each CTM to do its job..
