Hot Tips to Short-Circuit False Alarms

Recently, a major national security installation and monitoring company that receives more than 12,000 alarm dispatches a month reported in a customer survey of its top 20 false alarm offenders that the cause of their false alarms were devices/wiring, unresolved/unknown, device equipment adjustment and wiring/unresolved.

When service was initially dispatched on these accounts, roughly 40 percent of the offending problems were resolved through hardware repair, replacement or adjustment. However, nearly 50 percent of these alarm service calls where listed as unknown or unresolved. As a security industry technical person, your big question is: What can I do to reduce this high number of unknown or unresolved false alarm system issues?

The security system owner, integrator, dealer and technician must commit to increasing their level of dedication to reducing and eliminating opportunities for false alarms. While industry statistics emphasize that system user errors account for most false alarms, this month we will look at a variety of technical issues, tips and suggestions to help achieve “zero tolerance for false alarms.” The goal for all involved is to be a leader in your community and jurisdiction, and regain your customers’ trust in the rewards and valuable services of security technology.

Follow Basics of Cable Termination
Let’s look at several areas of a security system that many of you have noticed create false alarm problems. The first problem is intermittent continuity, also known as the notorious “swinger.” Many of these swingers can be traced to faulty connections in wiring and component terminals.

Make sure the basics on cable termination are followed, like wrapping a stripped wire end around a screw termination post in the clockwise direction. When the screw is tightened, the wire is pulled tightly around the connection, rather than being spread and pushed out of the connection.

This argument comes up often: Should I use solid or stranded wire? There are good reasons for both, with reference to workmanship problems and areas that can cause false alarms. If you use solid wire, there is no risk of loose strand ends shorting other connections when terminating.

However, there is a risk when using cutting-type cable jacket stripping tools of nicking the solid conductor and causing the solid wire to break and potentially cause an annoying swinger. It is recommended that you use a pulling-type jacket stripper with solid wire cable. Solid wire is also less flexible and this makes it harder to control when wiring multiple conductors in a cabinet or pulling through conduit.

Stranded wire, on the other hand, is flexible but can give you problems with stand ends accidentally shorting on other connections close enough to cause a swinger. I suggest using a crimped spade-type connector for stranded cable on a post-type screw connection.

If stranded wire is stripped with a cutting-type stripper, chances of nicking the cable are not severe, as the nick will only cut a few small strands at the most. I personally prefer stranded cable with an extra jacket for protection from staples, another source of intermittent problems.

Patterns Are Key in Troubleshooting
When troubleshooting intermittent false alarms, the trick is to look for a pattern. Sometimes they can be found with slight cable breaks and shorts as described above. A very subtle swinger pattern can sometimes be linked to changes in ambient temperature.

As we all learned in science class, solid materials like metal expand when they get warm and contract when they become colder. Closely associated conductors such as a nicked solid cable or a cable strand can slightly open or short a circuit with a change in temperature or vibration, causing a false alarm. I have also seen this in hairline cracks on the metal traces of equipment circuit boards.

Making wire splices with good compression type-B connectors or “beanies” is important. Make sure to use gel-filled connectors to avoid corroded intermittent connections in weather-exposed areas. These are for use on smaller (20-24) gauge solid wire. Soldering of wire splices is always preferred.

Test equipment specially designed for detecting swingers is very handy. Several manufacturers have testing products specifically designed for alarm system troubleshooting. One particular manufacturer is Act Meters Ltd. ( which has several pieces of test equipment for finding false alarm circuit problems.

A few test products to look at are the Checkmate and Son-of-Checkmate testers. These units use RF transmission or sound/light feedback, which allow a single tech to troubleshoot long alarm loops. These devices remind me of a homemade alarm circuit tester I made many years ago by modifying an audible loop tester and a pair of walkie-talkies.

Another device many veteran techs recommend is the Loopstick from Labor Saving Devices ( This is an RF proximity device that allows a tech to travel along an alarm loop and detect faulty intermittent circuit connections and door/window contacts.

FI, EMI Are Frequent Culprits
Radio frequency interference (RFI) and electromagnetic interference (EMI) can also cause false alarms. Any time you run long thin wires connected to sensitive, micro-powered electronic equipment, you risk them acting like an antenna and picking up RF and EM energy that can falsely trigger an alarm. The length, gauge and direction of the alarm wire can determine what interference will be picked up and transmitted to the alarm equipment.

Wireless can suffer a similar fate by strong RF signals overpowering the discrimination circuitry of the alarm receivers. RFI test devices such as the Zap Checker (see photo on page 24 of the August 2004 issue) from Alan Broadband Co. ( can help diagnose the strength and direction of RFI interference.

One method in combating influential RFI/EMI is using metal ferrite toroids, which can be snapped or laced onto the suspected sensor cable. These devices are placed on alarm cables leading to system components and will attenuate interference. They come in different types, such as ferrite #43 for 20MHz-30GHz and ferrite #73 for 10MHz range. Check Fair-Rite Product Corp. ( for more specification information.

Alarm sensors, such as acoustical glassbreak detectors (GBD), can be particularly prone to false alarms if not set up properly (see February 2002’s “Tech Talk”). While new alarm panels have CP-01 alarm prevention features such as cross-zoning (see “ The Quest for Idiot-Proof Products”), existing false alarm prone devices such as GBDs can be easily modified to reduce false alarms.

In the diagram at right, a basic PIR sensor is wired parallel to a GBD. In this case, both units must be tripped for the alarm to be reported. Notice in this circuit that a delay timer is used to create an “opportunity window” for the PIR motion to confirm that someone has broken the window and is now entering the property.

If someone just hits the window and trips the GBD, the local interior siren will sound, but because no one entered the PIR range during the delay time, the alarm circuit is not completely opened nor reported to the central station. This can substantially reduce false window alarms, deter further penetration of the property and report accordingly if penetration takes place.

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