By Mike Davenport
30 years ago, the industry installed mechanical magnetic contact switches. Once installed, the click you heard when the magnet was in proximity to the switch was a sign the switch was working. The high current would wipe the contact points clean as the door or window opened or closed.
Then around 1978 solid state panels and low current magnetic contact switches were born and gradually took over the market. With the emergence of low current panels entered the Rhodium & Ruthenium plated reed magnetic contact switches.
This enabled the switch manufactures to introduce a variety of switches which could be hidden in window sashes, and door jams. Prior to this almost all magnetic contact switches were surface mounted, and could be seen when anyone walked by a door or window.
High security switches prior to solid state panels were also mechanical. They had an abundance of mechanical switches in one housing which made it more difficult to defeat. One of the drawbacks was its size. It was a very large surface mount switch. The other problem was the solid state panel made these switches obsolete.
With low current panels came Triple Balanced High Security switches. These were made up of 3 reeds in the switch housing, and 3 magnets with opposite polarities in the other housing. This new technology which emerged around 1980 changed high security perimeter security.
REED MAGNETIC SWITCH FAILURE
As reed switches were used more and more, weaknesses were noted as millions started to be installed around the world.
Any high current around the switch could permanently close the switch in which if the door were opened, the switch would stay closed. Installers of these switches would go out on service calls and tap on the reed magnetic contact switch so it would work again. This is what the remedy was for a mechanical switch that would stick prior to solid state panels. Soon the service technician would realize once a reed magnetic contact switch stuck closed it needed to be replaced.
There are a number of reasons reed magnetic contact switches fail. Lightning is the number one reason for failure of a reed magnetic contact switch. Most installers think lightning has to strike the exact location where the switch is installed to cause the switch to stick closed. Lightning loves any type of magnetic field. This is an attraction. This is why so many televisions, speakers and other electronic items are affected by high current surges as well as the magnetic field lightning is attracted too. Lightning can be 3 miles away; and cause a switch to stick closed, and never affect any other alarm component in the security system. Imagine a switch which has been stuck close due to lightning. If an intruder entered a home or business when the alarm system was armed, the siren would never go off upon entry.
The number two reason for reed magnetic switch failure is the installer improperly striping the wires prior to installation. Most switches have hookup wires attached. The installer almost always will shorten the wires and either tape and solder the wires from the panel or junction area to the switch or use B connectors. Installers do not understand the force they put on the reed inside the switch housing when the wires are stripped. Most installers hold the plastic switch case, and jerk the wires as they strip, causing the reed inside the switch housing to crack or break. Initially when this happens the switch could still function properly, but after a short time, if not immediately the switch will fail and cause a service call. The proper way to strip wires is to hold the wire -- not the plastic case -- and strip gently. This will help insure the reed has not been compromised during installation.
The number three reason for reed failure in a magnetic contact switch is drilling a hole to small for the switch. If you drill a .375 diameter hole for the switch, allow a small amount of extra room. A number of installers will drill the hole, connect the wires, and press the switch into the .375 diameter hole, and walk away. DO NOT.
Put some silicone or other compound of your choice which will insure the switch doesn’t work its way out, and most important helps absorb swelling and contracting of the door or window frame.
The number four reason for reed magnetic switch failure is Electro Mechanical Interference. A power line grid over or near a home or business will cause reed switches to stick. This affects many High Security Triple Balanced magnetic contacts which use three reeds, and can cause concern since these switches are the first line of defense in perimeter security. Triple Balanced switches are highly resistant to defeat by and external magnet, however if lightning causes the reed to stick closed, it can be compromised.
REPLACING REED SWITCHES
October of 2006 the newest Triple Balanced technology was UL/ULC listed and introduced by Nascom, Inc. of Kalama, Washington, the U.S.A. This Triple Balanced switch does not use reed switches. It uses magnets in the switch housing as well as a circuit board, with a digitally matched magnet for actuation. It is not affected by Electro Mechanical Interference, lightning resistant and is the most secure Triple Balanced High Security switch available in the world today. These switches are installed in banks, government installations, and airports and are the most secure switches on the market today.
In 2002 a new technology was introduced for home and small business use. It won the best of ISC East Alarm Association show. It is called Magnasphere. This technology replaces the reed switch and is small enough to be enclosed using a .375 concealed housing or a .375 surface mount housing. Nascom is the first manufacture to have UL/ULC listing for this new technology inserting it into small plastic switch housings so an intruder cannot distinguish between a reed switch or the Magnasphere high security technology which has a high resistance to defeat. The Magnasphere technology is resistant to Electro Magnetic Interference, and is lightning resistant.
FALSE ALARMS & SERVICE CALLS
Reducing service calls, and false alarms is a major challenge to alarm and security companies around the world. When I entered the industry, almost everyone I spoke to had 15 to 20 years of installation experience.
While attending the 2007 ISC West International Security Conference in Las Vegas, the U.S.A., one of the common statements I heard was, we do not have enough veteran installers. The average experience is less than 5 years.
As a new class of installers emerges, they have exceptional ability in grasping and understanding electronics & IP solutions being introduced by manufactures, however their lack of installation experience is something the whole industry needs to work on.
With over 30 years involvement in designing and manufacturing magnetic contact switches, I go out some time with installers to insure I am up-to-date in the latest window and door designs that affect the installers.
I absorbed last week, an installer putting self adhesive switches on a sliding window. He took the tape off the back of the switch stuck it on the window. He positioned the magnet across from the switch, and stuck it on.
His hands were dirty; he never bothered to clean the surface with alcohol to insure the tape would not come loose. It was a service call waiting to happen.
I shared with him if the tape is put on a clean surface and the manufacture of the switch actually uses the very best tape, the strength of the tape adhering to the surface will increase over time, reducing a chance of a service call.
Another reason for service calls due to installation is installing a switch and magnet is the incorrect alignment. A magnetic contact using a reed switch can be installed having the magnet either end to end of the switch. Parallel to the switch or in an L configuration to the switch.
The same day I was out with the installer, he proceeded to put the magnet and switch in a T configuration, which caused the system not to arm. He stated the switch must be bad, but once I showed him it was the incorrect configuration, he understood, and corrected his installation.
False alarms and service calls are also caused by the companies who insist on buying the cheapest panel, cheapest switch or cheapest wire. These same companies proclaim they purchase the finest equipment available. They also justify buying cheap components by stating, after the alarm system is installed 1, 2, or 3 years they get extra revenue from the customer for any service calls or equipment failure, so they do not feel it necessary to buy the best. Worldwide cities are clamping down on companies, and customers who have false alarms. Some cities do not even respond. Most impose fines. Company who install alarm systems need to purchase the very best equipment, not the cheapest.
For a short time, a company I am familiar with tried purchasing a few products from two China factories. They trained them exactly how they wanted the products to be made. The company was assured there parts were tested properly, and were assured the part was exactly what was specified. Shipment after shipment they tested the parts. 13% failure out of the box. They would send e-mail showing the correction, and they would send back to them perfect samples, but once the new orders were received, 12% failure, 15% failure. The company had to un-package, test, discard the failures, and repackage.
Over the past 30 years new shapes, sizes and types of switches have been introduced to the alarm industry for perimeter use. Some of the newest are industrial Track Mount switches for garage doors.
Another new switch is for Curtain Doors for industrial rollup doors. One of the most popular is the Miniature overhead door switch used for overhead door floor installation or man door installation.
For residential installations introduced recently has been what is called the CAP switch. This switch is a sub-miniature surface mount switch which can be installed in a window sash, in some window tracks, and is small enough that if installed as a self adhesive switch is rarely noticed. As alarm professionals, we must always offer our customers the very best equipment -- best panels, best high security switches instead of reed switches, best PIR. Let your customer view the best selection of products, and let them decide the quality they want.
It’s best for the customer, it’s best for you the installing company, and best for the alarm industry.
Mike Davenport is Founder of Nascom (www.nascominc.com).
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