63945982 Tricks of the Burglar Alarm Trade PALADIN PRESS

7/29/2019 63945982 Tricks of the Burglar Alarm Trade PALADIN PRESS

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PALADIN PRESSBOULDER, COLORADO


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Tricks of the Bwglar AbrmTrdeby Mike KesslerCopyright @ tro Uy Mike KesslerISBN G87364-550-2Printed in the United States of AmericaFirst published in 1984 by Mentor PublicationsPublished by Paladin Press, a division ofPaladin Enterprises, Inc., P.O. Box 1307,Boulder, Colorado 80306, USA.(303) 443-72s0Direct inquiries and/or orders to the above address.All rights reserved. Except for use in a review, noportion of this book may be reproduced in any formwithout the exprcss written permission of the publisher.Neither the author nor the publisher assumesany responsibility for the use or misuse ofinformation contained in this book.


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( CONTENTBTHE EASIC AURELAR ALARI'I SYSTEFITHE FROTEtrTIVE trIRCUIT. 5SHtrRT trIRCUITS BCLNTROLS 1lBELLS&SIRENS .T7TESTINE hIITH A I"IETER. 205EN50R5. 23THE FLUNEER SWITCH.. ?4THE 1'IA6NETItr ST{ITCH. 26THE LEAF SWTTCH. r r. t... r r r 2qTHE I{ERtrURY ShlrTCH.. .......... 30TRAPS, r.... 3?THE VIBRATION DETEtrTBR 34LACrN6, .. r.. r., r. 35swITcH HAT...... 37PROTEtrTINE 6LASS t.... ..... i I r. 3ETHE PHETOELEtrTRItr DETECTOR.. 48AREA PRBTECTItrN DEVICES.. 5c'THE PROXII,IITY SENSBR. 5g

aTHE SHUNT LOCH. 59TRDUBLESHOOTING. 62IHSTALLATION NBTEs. ..... . 74spEcrAL TtrBLS, PARTS & TECHNTtrUES. . EOEGUIPI'IENT COST REFERENCE... 89

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FORET{ORD

Anything worth learning is worth learning well, and learning Eiol6e-thing well calls fsr some degree of effort, The objective of this bookis to minimize that effort by avoiding the use of technical jargon,cryptic diagrarns and references to electrieal theory. However, thisdoesn't rnclan the information contained in this book will jurnp off thepages and burrow itseif into the casual reader's brain.The "sirnpli{ied" instructions packed with most do-it-yourself burg-ar alarm lrrts are usllally quite easy to follow, leading one blindlythrough the haphazard. installation of a mediocrel systern; explaining"how to do itr" r*ithout a word about what one is doingr oF why- As aresult there are thousands of so-calteO blrglar alarms in current use,many o{ which can be defeated by the least sophisticated methods-- andaost of which will rnalfunction nithin a {ew months, often leaving thedo-it-yourselfe'r with a collection of useless hardware fastened to thenal I s-Flost burglars can easily recognize an irnproperly installedr simpleto defeat, do-it-yourself lrrt burglar alarn jugt by glancing at itscomponents: the o{ten {limsy control box, drooping wire:i, cheap shuntlocks and imtrroperly e!p.U_ed window foil with sloppy connections. I'lanyof these packaged kits are relatively inexpensive (cheap) n thereforeincreasingly comnonplace. I'lost contain essentially the lrne type ofparts-- with instructions to install thern in essentially the tlnl h,ayr

therefore they are relatively easy to recognize and de{eat by a numberof simple methods' The most common of these methods is salled ,'jumper-ing. " This is a technique used effectively by burglars to ',by-pa5s"cheap or improperly instalted alarrn systems. There is a very simplecountermea5ure to the jurnpering technique, but it is never explained in'simplified" instruction manuals, and rarely mentioned in books. Inorder to apply this countermcrasurEr ctne must understand the jumperingtechniQUEr which calls for thorough familiarity nith the nature o{closed-circuit burgl.r rlrrm systlmr.This book explores closed-circuit ("supervised") wiring in detail,concentrating on the basic principles that govern all closed circuitburglar alarms, ranging from those found in tenement apartments andcandy stores to those used in mansions and bank vaults. Once theseprinciples are understood, they may be apptied to any type o{ closed-circuit burglar alarm system. The best way to learn from this book isto read it through fron coveir to cover, passing over any word or s;eg-ment that seerns vgguer Br a bit too technjcal. Very often the answerttr a question that arises in one section will be found in a {ollowingsection, or in the next paragraph. None of the diagrams are scheratic:sBmE are self-explanatory pictorials, while others are simple linedrawings. Each drawing is thoroughly supported by accompanying text.It is true that "one picture is worth a thousand words;,, and it'salso true that one hands-on experiment is worth ,nore than a thousand

pictures: The serious reader is well advised to obtain a sampling ofthe components described throughout this book and assemble a "benchsystem" (sn a workbench ffr kitchen tablel, and follow each separate


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setrtion B+ the book with an actual experiment. This is precisely theteaching method used in all clagsroom and coFrespondence cgurses onsecurity electronics-- and it works! Every str-rdent of a burglar alarmcourse is given a control panel, a coil of wire, one each of a varietyof sensorsr a power supply and sotnEr mi=cellanecrus parts; and is guidedthrough a nurnber of "bench experiments, " After the course is complet-edt the same cornponents are used in an actual installation or they re-main part of a perrnanent bench system. (To be used in conjunction withthe te=ting of new conponents and devices. )It is recorntnended to readers who intend to install a burglar alarmsystem to set up a "bench system" first. After becoming thoroughlyfamiliar nith each component and its particular function in the benchsystemt stretch out a few yards of wirer apply a foil pattern to a panE!of glass (even a mirror), and practice troubleshooting with a test me-ter. To most noviclsr a bench system is like a set of electric trains--with a serious purpose.Security electronics is a fascinating world of ultimate gadgetry, afield that presently o#fers golden opportunities to any competent, mot-ivated individr-ral. Furglar alarms are def initely in, and the prof itpotential in this business is impressive. A burglar alarm sjdeJjne canbe operated out of a closet, using an ordinary trar. And the initialinvestment is nominal.For example, one wey to start up is install a system in y61ur gtwnhomet then do the same for a friend or neighbor-- at a fair price. The

price should at least recover the cost of both sets of components, enab-ling the purchase of toorEr equipment, thus an inventory is establishedwith practically no cash investrnent. Each subsequent job generates aprofit while providing valuable experience. As your proficiency grops,so t*i1l your income. Thousands o{ profitable installation companieshave started up in exact-1f-ElFway; many of them are highly sutrcess-ful today-- and there's plenty of room for more.The techniques and equipment described in this book are not restric-ted to residential installations, but apply to commercial premises agwell. In factr corntnercial premises are usually easier to nire and of-fer exceptionally high profits tn the Jeasing installer: In a leasingarrangementt the initial (installation) charge should absorb the costof equipment; the system remaing the property of the installer, whoagrees to provide service and maintenance under contract (payable mon-thly. l Service contracts ghould not provide for {ree service when danr-age or tampering is the cauge of a problem. Leaged burglar alarm ser-vice contracts range from 15.OO to 5OO.OO per month, depending g'n thesize and sophistication of the individual system.ldhether the reader intendsalarm system or to strike outplace to begin. The next stepBome hands-on experience. Eachpersonal satis{action, and cash

to install only his (or her) own burglaron a nelw careerr this book is a goodis to assemble a bench system and getstep thereafter will be rewardingi insavings-- or handsome profits.Vi


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e

THE BASIC BURELAR ALARI.I

alarm system consists o{ three separate segments,the control pennl, and the protective circuit. Theare wired togethe'r as shosrn in Fig. l-1.A basic burglarthe bell cireuit,separate segments

PNOTECTIYEEHCLOSURE+f -'-,---------.'' lrtl

./BELL CIRCUIT

tCOHTNOLIilSTNUNEHT PROTECTIVECINCUITIt: ; AELL


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As mentioned above, there is a separate pohrer supply, (a 6 volt, heavy-duty lantern battery), inside the control cabinet for ringing the bell.The protEctive circult porer supply does not serve thr bell circuit inany way!Fig, 1-2 is a closer look at the insideFastened to the inside of the cabinet doorcircuit board upon which are mounted twoshownasA&8.

o{ a wired control panel:is the cnntrol. instrunent, aelectro-mechanical relays,

Flol!oonorl

6 VoltBat tery

Fisuru l-2Situated between these two relays is a hole through which the reargection (body) o{ the ttN./BFF key-switch protrudes. A pair of wires(not shonn) is pulled through this hole from behind the board andconnected to the key-switch.Situated below the relays and key-switch is a connecting strip withsixt separated terminals, numbered I thru 6. Terminals I & 2 are ad-dressed to Relay Ar which is the bell relay, Terminals 3 & 4 are also


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addressed to Relay A. Terminals 5 & 6 ar! addressed to Relay B, whichs the prottctive circuit relry. Note the connections to thesn term-nals: The bell circuit wiring is connected to Terminals I & ?. A sixolt battery; (for the berl), is.onnected to Terminars s & 4. Therotective circuit is connected to Terminals s & 6. The wiring for theell and protective circuits is drawn through ,,knockout,, holes in theear of the cabinet' The 6 volt battery is attached to Terminals s & 4y a short pair of 16 to 14 gauge nires.rmagine that the components rle've covered thus far are set up .,n aest bench' arranged as shown in Fig. 1-1: Rotating the key-gwitch tohe CIN position will arr the systemr-meining it is'iet up,, to functions a burglar alarn. The rray tn activate the alarn is to somehon inter-upt the flow of current through the protective circuit, nhich may beone either by disconnecting the battery-- or cutting a wire. Thr.fol-owing is a detailed explanation of how the control instrument governsthe separate functions of the belr ano frotective circuits,Relay A is the bell relay- hlhen the properly rated power source ispplied to it, (6 volts in this example), its contacts are purled to-ether, "latching" in place and proriding a conductive path between thePower strurce (at terminals 3 & 4t and the betl. Thera are two opens inhe path between the power supply attached to Terminals s & 4: one isontrolled by the key switch, lrte other is controlled by the protect-ve circuit, (Relay E.) rn order for the bell to ring, the key switchust be turned oN and the flow of protecii;; ;ir.;it .,r...nt must benterrupted.

Relay B is the protective circuit relay. rt is totrlly tndrprndrntf the key-switch. The protective circuit ig consiantly energized byhe 5 volt battery, and will remain energized as tong as this ,.supcr-Yisory" current flow is not inG-upi.o. The flor of s volt energyhroughout the protective circuit is called ,,supervisory,, current be-ause it monitors the status of the circuit.

LJ slllTcll rERnlHnLt

Fisurr l-SBurglars are not so accomodating a5 to deliberately disconnect therotective circuit batterY ar cut s wire to de-energize the protectivecircuit relay and causel an alarmr so sone form oi switching devicesensor) must be applied to =ach point-o{ potentiar - entry and wirednto the protective circuit- Fig. l-3 shows hon to wire any sensor.


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One "leg" of the protective circuit pairstripped and attached to the terminals o{device serves as a ,neans ts ra*e or breakthe Frotective circuit, as in the example

is cutl the severed ends arethe switching device. Theelectrical continuity throughof an ordinary light switch.

B( CL08ED ) 3ItTCH( cLoSED )e+( OPEH )3 volts

EELL CIRCutrT VFigure l-4

In Fig. 1-4, the closed switch provideg continuity through the pro-tective circuit. Relay B is held closed by the flow of current fromthe protective circuit battery. Note that when relay B is closedtrelay A remains oPE!n-- therefore the bell cannot ring.B( oPEx '

SUITCH( oFEll )+f,+( cLoSED )

FNOTECTIVE CIRCUIT y' 3 voltsBELL CIRC]/IT 7

Fi Eurr_.L:5In Fig. 1-5 the switch (pictured) is open, which de-energizes RelayB, causing it to open. lrlhenever the key-stuitch is turned trN (systemoperational) and relay B snaps open, relay A will simultaneously snapclosed, activating the alarm. The only way to disengage the bell isto turn the key-sfritch to the OFF position'The drop-out action ofterruption of current {lot*occur for a fraction cf aing the protective circuitfatched in,

Relay B is extremely fastthrouEh the protectivesecond to activate the bellwill not release the bell, therefore an in-circuit need onlYcircuit, Restor-relay clnce it has

n[MS:


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='._=-,.=I::-::::::I:::-::::::L-_'r_To present this concept in its simplest fgrm, the protective circuitdescribed in the foregoing section is depicted in a short, straight-line configuration, contsining only one siensclr, hlhile there arc situat-ions that call *ar such a short run of wire and just one sensor, theyare rare- fn most casesi a protective circuit will be routed throughseveral roclms of a premisesr crn different levels, and will containabsut a dozenr sEparate sensors. Regardless of a protective circuit.sarea of cl]verager DF hPw many sensors it contains, the basic principlerernains the samet The protective circuit should alway5 be perceived asa pair of wires with a pohter supply and a number of switches connected

in serjes- The open ends of the pair are attached to a pair of scrGlhrterminals in the contrtrl panel, (E & 6. )In electrical terminology the r*ord serjes neans a continuous string,like a group of people holding hands in a circle. To further clarilythis analogyr remember that the words circle and ctrcuit derive fron ar---+

silTcHEs

$re see that a "pair"circle of connected

common root:Eompare Fig. ?-l with the diagram inFig. 2-2 (next page. ) Study bothdiagrams and you will find the onlydifference is that the protectivecircuit in Fig. 2-Z has four rensctrswired in series, while the one inFig. 2-l has only two, and the bat-tery is situated on the other sideof the control panel - 0therwise,both diagrams depict exactly thesaroe thing I El continuous, seriegcircuit, consisting of a singlestring of wire connecting a nuorUerof cornponents together. Fig. Z-t isa series circuit, so is Fig. Z-?,If this simpte principle is clearlyunderstood, the folloning sectionswill present no problerns.Fig. 2-2 is a protective circuitra control panel; E pair of wiresextending out to a battery and foursensors wired in series.of wires is just a convenient waycomponents,

,1,

="*-

of In Fig. 2-lproducing a


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COHTNOLPRHEL FiEure 2-2.The phantom line of arrt:ws in Fig ?-2 depicts the flow of currentfrom the batteryr through the entire protective circuit (including the

protective circuit relay in the csntrol panel ) , through each of the5,ensors, and back to the battery. This diagram is representative of asimple, straightforward installation, such as a row of {sur windows onthe same wall.Ag previsusly mentioned, most installations call for about a dozenprotected points, which are situated in different rooms and on morethan one level of a premises, To begin a protective circuit at onegiven point and carry a continuctr-rs pair of wires to each consecutivepoint nould be doing things the hard Hey. A much easier way to dis-triburte a protective circuit throughout a premises is shown in Fig. 2-3(next page. )

Study this diagram and you'll find that the "main circuit" (runningfrom the control panel to the batteryl is an exact duplicate of theprotective circuit in Fig. ?-2, with a {ew additions:The layout of this hypothetical installation makes it convenient tosituate the control panel at crne end of a row of four nindows (sn onewall) and put the battery in a closet at the other end o{ the wall-This is the "main circuit" and it centains four sensors'. (trount them. )A second, separate circuit is started at another location of thepremisesf covering five windows and two doors, (seven sElnsclrs-- countthem. ) This circuit is tied into the rnain circuit at Ar in the samGl

way aE a sensor would be connected. This circuit is ntrw known as"loop" A of the protective circuit.Another loop is seen at B. Loop E contains only trne sensort (pro-tecting a roof-hatch, cellar door, etc. ), and it is tied into loop A.A third loop, also containing one sensor, is seen tied into the maincircuit, at E.Follow the arrows around this circuit (from the battery and backagain) and you'tl see that no matter how many loops are addedt and nomatter whrrr they are connected, the final e{{ect will be the same. Ag

complicated as il. might seem in diagratn formn in principle we are deal-ing'rith a huge circie-- produced by intercsnnecting several, separatepairs of wires, (looPs- ) 6


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a +i- r-----a-Ji---*--+'l' :

+BRTTENf

Figure 2-3.It is important to mention that, technically, it makes no difference?hele the battery is situated in the protective circuit. The hatteryin Fig. ?-S could be removed from its present location and (after thevacated wire ends are spliced together), connected anywhere else-- inthe main circuit :r in loops A1 B or e.The protective circuit battery ,nay be wired in a different way andplaced inside the control cabinet along with the bell battery, which issometimes done. However, there is a good rErascrn why this practiceshould not be followed in sorne situations. For reasons which will beexplained in the section on SHORT CIRtrUITS, the protective circuit bat-tery should be situated a good distance away from the control panel andconcealed whenever the protective circuit parts are accessible to tarnp-ering by visitors to the premise!s, customers, ernployees, etc-

COHTROLPRIIEL

HRn{ CIFCUIT


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EHORT CIRtrUITEr-!-rratlll!lrtlllllllrllltrrlll

To Bell-tJl-Jl-

I

Protective Circuit +-+=J

Fioure 3-lFig. s-l shows a protective circuit wired to a control panel' Hotethat the protectivr.ircuit battery is situated inside thc control cabi-net, next to the bell battery. ixamine the wiring of this protectivecircuit: one teraninal of the two-cell battery is attached directly toTerminal 5 of the control instrumentn leaving G'ne vacant battery terrn-inal and one vacant terminal, (6) r on the control instrument' Theprotective circuit is wired directly to these vacant terminals' Thepath of the arrows shows that the supervisory current from the batteryflows through the protective circuit, (and the protective circuit re-lay), just as it rrould if the battery }'lerE! gituated outside the cabin-et. However, wiring a protective circuit in this manner offers thepotential {ar cornprornise, making it easy for a knowledgeable burglar tobypass the entire circuit by imposing a "shc'rtr" (short circuit)t atssrne point close to the control cabinet'

In the giame way that water will always seek the lowest level, elect-ricitywillalwaysseektheshortestpathtofollow:

. Fisurr $-2Fig. 5-2 depicts a simple circuit, a two-cell battery connected to alarnp by a pair of wires, Note the unimpeded flow of current throughthe entire circuit, causing the lamp to light'In Fig, 3-3, (which is identical to Fig. 3-1) t we see that a shorthas been irnposed across the pair, (by attaching a "jumper" wire')

ii_

I

volts)


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'-* ._JTo Bell Protective Circuit

*ftLJ

Fisunr 5-5Fig. s-5 is identical to Fig. s-1, with one exception. This is aproperly "supervised" protective circuit, with the battery situatedoutside the cabinet. Note the effect of imnosino e short at the ErmEuEEiloG! EnE! caDlnet. Note the effect of imposing a short at the samepoInTEs in Fig. 5-3: The flow oi supervisory current is divnrted bythe short-- but in this ca:ie the protective circuit relay is deprived

SHORTEIF.1 snonr

Fiqure 5-5Note that the current flow has been diverted by the short, returningby the shortest possible path back to the battElry. Electricity floursrith incredible speed, from negative (-) to positive (+) r and willalnays follow the shorte:t porsible rclttr.

FlEurr 3-4Fig. 3-4 is identical to Fig. 3-2, with one important exception. Ashort appears at A. Note that the supervisory current ir diverted bythe short bnd returns directly to the battery. Also note (in Fig. S-S)that even though the entire protective circuit has been by-passid, thaprotective circuit relay doesn't "know" this. The current still flowsthrough the relayr energizing it, thus the sensors in the protectivecircuit are unsuFervised.

To Bell-+-rotective Circuit

--lritrlLJ

il(lt?

6 volt


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r]f energyr and will drop out, activating the bell circuit.Some shorts are accidental, caused by u;11rn Er damaged insulationthat causeE; both conductors of a pair to make contact. But imposing adeliberate short is called "by-passingr" and is the *avorite techniquea{ sophisticated burglars. In one example, a commercial premises wasburglarized and the alarm system failed t61 function' An inspectiondisclosed that the installer had wired the protective circuit ulith thebattery inside the control cabinet. Because the public had access tothe protective circuit during normal businetss hoursr sc,meone had pushedan ordinary straiqht-pin through both legs of the protective circuitpair just a few fiet away from the csntrol panel, shorting out the

entire protective circuit.To surnmari zecircuit batterYdistance fromcircuit betweenan alarrn.

the foregoing in simpler terms: l,lhen the protectiveis situated outside the control panel and at a remcteit, an attempt to "short out" any part of the protrctivethe battery and the control panel. will instantly causeIt is often more convenient to place the protective circuit batteryin the control cabinet (as shown in Fig- 3-1) and when the possibilitysf a cornpromise atternpt does not exigt there is nothing u'rong withdoing it this way. In fact, when a control panel with a built-in powersupply is used, there is tittfe alternative. However, unless an "end-of-the-line resistor" tyFe control panel ig usedt this wiring methodleaves the protective circuit vulnerable to a gimple by-pass.The ,.end-of-the-line registor" panel will seem sonewhat con#using tothe novice at this stage, but it is a relatively simple principle tounderstand: All electrically conductive materials present a measur-able amount o{ specific resjstance to the flow of electrical current'The amount of resistance (which is measured in "ohms") depends on thetytre of material and its mass, (gauger in the case of wires. l Forexample, a 2O yard length of ?2 ga. cg1PPer wire will show a specificlevel of resistance when measured with a precision meterg naturally theamount will be legs than 21 yards and more than 19 yards.The protective circuit relay of an end-of-the-line resistor controlpanel is sensitive. to an abrupt change in the specific resistance of aprotective circuiL. trlhen the protective circuit's overall regigtancei= measuredl which will include the sum o{ the specific resintancelevels of every 5ensor in the circuit, this type of control panel ad-justs to the specific resistance of the protective circuitr with a verynarrow nargin of tolerance. The slightest fluctuation, guch a5 a by-pass attempt, will cause it to drop out'This method is not new, it ig borrowed from the principle o{ thecentral statjon connectitrnr by which bank alarms, etc' r are! wired byleased telephone lines to a nonitoring station.

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CONTROLEE13---IIIlrEl-I3

I'lost s{ the components used in burglar alarm systGxn:;, such as bells,ire, batteries and sensors are designed to perform a single, specificunction, therefore the only factoi to consider when selecting theseitems trom the wide variety of available brands is quality. For exam-Ple' a bell is a bell and is expected to dtl nothing rnore than make anoise' There are many bells avaitable on the equipment market, most oftich are veFy well rnad and priced within the -sarne rangE!. rf a bellears the u'L' label and is sold by a regular alarm equipment dealer,this is adequate assurance of reliable quality.The same can be said for wire, batteries, po'er supplies and sen_srtrs' from the simplest sr*itch to the most sophisticated rnotiondetector' HoweveFt the same cannst be said for control panels becausethere simply arE! too many different brands and models available, sorlaf which provide numerous atrcessctry functions in addition to the prirn-ry function of activating a signal when the protective circuit isisturbed.The control panel described in this rnaterial is known in the burglaralarm trade as the "1oo control" end it has been the standard of thendustry for tnany yeaFs- The 1oo control consists of a plain, sturdynclosure, (cabinet), with a t'lodel loo control instrument mounted onthe inside and a two-position ON./EFF switch shotring on the outside,nothing mEre. In spite of the many high-tech alternatives available onthe market, the loo is preselntly in us. in millions of commercial andresidential installations' These panels ere preferred by many comrnrr-cial alarm contractors for use in leased alarm systems, which is a sig-ni{icant testimanial because leased burglar alarrns are profitable pnly{ they are trouble-free and the equiprnent is cost-efficient.The loo is an inexpensive, reliable burglar alarm control which maybe expanded upon by adding any number of optional accessories such as aPermanent power supply ("power pack"), entry./exit delay timlrr bell cut-++ timer, AC switching relay, and rricrre. These actressclry modules arE!quite easy to add to a basic contrsl panel at any time after the systemis installed and operational. The alternative to using separate mod-lles is to purchase a control panel with all of the desired accessoriesbuitt in' hthile this is a suitable alternative for the experienced in-staller, a novicE is likely to find a sophisticated, multi-functioncontrol panel to be baffting. This is why the forrnat of this materialis structured around a sirnple, basic control panel, which the noviceinstaller is well advised to start out with.Listed below arE! a number of useful accessory control features. r+preferred, there are many control panels avaiiable that o#fer anycombination of these features, and mor..r ES buirt-in options.

1l


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PtlhlER PAtrKSrA popular alternative to operating a burgtar alarm systltn ctn tempor-ary batteries is to use an Atr-dependent transfortnerr called a perrarrentpo{rer supplyr BF pa{ter pack- But a FElrmanent power supply should nevFrbe used without attaching a trickle-charging, stand-bv- -battery to itfor maintaining power in the event of an AE failure or deliberatet Fre-burglary tamp=iittg with the house wiring from outside the premises'

110 ACPower ReceptacleFiourc 5-1.

Fig. S-l shows the layout of a l'todel loCI control instrumentr niredup witt " number trf accessc1ry control-{unction modules'A is the power supply Hith a stand-by storage battery attached at B.Terminals I & ? of the power pack are cclnnected (trt to 11O ACteither directly, (using lEl 16 gauge wire), Pr via a plug-intransformlr, twnlcn will be included with the unit when purchased' )Terminals 5 & 4 of the power supply are wired to Terminals 3 & 4 ofthe control panel, providing a permanent source of 6 volt energy {orthe bell. These p61wer pack terminals replace the bell battery shown inprevious diagrams.Terminals 5 &.6 of the power pack provide a pernanent source of 5volt energy for the protective'circuit and are wired in the samr manneras described in Fig, 5-1. These power pack terminals replace thc pro-tective circuit battery shown in previclus diagratns.

ETAND-BY BATTERYTTerminalsT&Bof

(8. ) I+ the Atr Powerto battery suPPort-the power pack are wired to the stand-by batterytIiii=, thl power pack will simultaneougly switchEecause the standby battery is under continuous

12

TO 11O ACt i ol'r qui f .hBELL non E - L-? rr

Hr--....-..,'..'.--..---=Bell Circuit lrLProtective CircuitI 2 3 4 5 6

E3t I JDcI tttl-r-tt2 tT1 IsIa rlaTO A B


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charger it retnains Perlnanently energized tE peak capacity and doesrequire periodic replacement.ENTRY/EXIT DELAY TIFTERc

not

The itern shown at D repres;ents an entry/exit delay timer module.Note that it is wired directly into the protective circuit. Thisdevice has two separate timing circuits, (ENTRY and EXIT), both ofwhich are adjustable to provide a delay period #rom O to 6O seconds.The EXIT delay enables the user to switch the system 51n and leavethe premiseg without activating the alarm. Likewise, the ENTRy delayprovides sufficient time to re-enter and switch the systern off beforethe alarm activates. An ENTRy delay timer should always be adjusted tothe shortest possible delay period, for obvious rGE: An excessivepre-activation delay might afford a burglar sufficient time to locateand forcibly disable the control panel before the system activates.

TIFIED BELL trUT-OFFrF represents a timed bell cut-s{f device, which ig wired into thebell circuit. This device automatically cuts otl power to the bellafter it has rung for a pre-selected time. Twenty to thirty rninutes isplenty of time for a burglar alarm to sound, whether the cause is anentry attempt trr a malfunction. (l'lany localities have ordinances thatrandate a 20 - 30 minute maximum ring-off period for burglar alarms.)

ffi EI{ITtrHINB RELAYTH is an AC switching relay. It is connected (g) in parallel to thebell circuit pair. lchen the alarm is activated, thr rtml currrnt thrtrings thr ball rlto Enargizrr thir rulry, causing its high-vottagerated contacts to close. These contacts are wired directly to ttre term-inals of a light-switch. Elosure of this relay's contacts will thugturn on whatever lights the switch normally controls, which might be asingle table-lamp or a string o{ exterior floodlights. The cornbined ef-fect of a loud bell or siren, (or both), and bright liqht will usuallydrive off the most brazen burglar.Note that the AC switching relay is connbcted to the bell circuitwiring between the control panel terminals and the bell cut-off deviceat F- I+ it were connected anywhere beyond the bell cut-off, it wouldbe de-energized along with the belf wtrEri ttre tirrer's contactg opened.This would turn off the lights, too, which is not desirable.

].IULTIPLE ZONESTIt is often desirable to wire nore thanthe same burglar alarm system. The reasonthe system into separate ,,zonesr,' each

one protective circuit intofor doing this is to divideof which may be temporarilyl3


21/98

,,shunted" (removed, or "by-passed") from the system without affectingthe remaining Zot'|rS, This capability is valuable in situations where aproblem in a protective circuit is discovered prior to closing thepremises and cannot be serviced until the following day' hlith a singlezone system this would require that the entire systern be switched offtleaving the prernises totally unprotected'

A trick which is used successfully by rnany burglars is that of incon-spicuously passing a raaor blade through a strip of protective {oiI onthe interior glasi of a business premiges during normal busine:r's houretknowing that ifri= inconspicuclus damage to the protective circuit willforce the owner to either remain overnight in the premises or leave itunprotected, which is usually the choice of a tiredr unsusPecting shop-telper who doesn't want to wait several hours {or a serviceman'

+ Control Panel

Protective Circuit #lBell /ci".uit I I6 Yolt 8el1 BatterYProtective Circuit #2

Flqura 5-2.The use of a two-zone control panel in a good way to counter thistrick. Fig. 5-? depicts the layout of a two-zone system' Note thedifferences betneen this layout and thos! seerr in previoust single-zonG!diagrams: This control insirument has a gcond Prottctlvr circuitrelay (E) and anothrr peir of terminalr on the connecting strip' (7 &g) which accornodates the additional protective circuit' Everything

else is the 58fl1E.Assume that protective Circuit *1 is dedicated exclusively to supclr-vising the premises nindow {oil and nothing else, while Protectivecircuit l]2 is dedicated to the remaining sensoFs used in the system--which includes a nbtlon drtrctor device: Several possibilities existin such an arrangement. One possibility is the burglar(s) who sabotagethe foil pattern, believing that the entirF sysl:m- has been disahled'will attempt to break in via a back-door]etc., which (unknown to them)is protected by a sGlnsctr in Protective trircuit ll2, (zone 2' )Another possibility is that the burglar(s) will break and enterright through a glas5 pane, which is lefi unprotected because of thedisabled zone. Bnce inside, howeverr- they- witl enter the energizedfield of the motion detect;;'Oeviie, inicn 'is wired into the activecircuit, (Zone 2. ) 14


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instead of just one. But in view of the foreqoing advantages it makessense to go the extra mile, The advantages o{ a multiplE!-zone =ystemare obvious and well worth the extra effort in the long run.In comparison with the simple, straightforward design and aFpearanceof a basic, single-circuit control panel r a multiple-zonet multi-feature control panel might he an intimidating Prospect for a beginner.It should be kept in mind, however, that regardless of how many separ-ate zones a given control panel r*ill accomodate, the basic principlesoutlined in this material will apply to each of them.Due to the I arge nurnber of different control panels available fromthe various manufacturers it would be irnpractical to attempt adescription of each of thern in one book, because by the time this bookis published there undoubtedly would be morEr. (Few of which will of{erany really useful n new features. )There is no question that some (or atl) of the accessory functionsdescribed above are necessary for certain situationsr but a good ruleto follow r'rhen selecting a control panel is to avoid those which seemto promote gadgetry as opposed to sensible technology and are not trulyuseful or practical, While seductive lights, buzzers, whistles andbells serve an actreptably frivolous purpose in luxury automobilest suchredundant {eatures in a burglar alarm control are o{ten more confusingthan convenient.A listing of price averages for burglar alarm equipment is found atthe end of this book. The prices given are the typical retail cost ofreliable, professional-grade equipment. The reader whs plans toinstall more than a few burglar alarms will savE considerably when pur-chasing equipment directly from a wholesale distributort but the begin-ner is well advised to patronizr an experienced retailer who is notopposed to answering basic, "stupid" questitrns.blholesale distributors discount up to 4O7. oft retail and thus dependon brisk, high-volume sales, which is r{hy they have little patiencewith "girnme one of those and where do the wires go?" custsmers. Awholesaler's counter is usually busy with large quantity orders fromworking installers who know exactly what they needr and how many dozentso the novice who's looking to save a few percent on the cost of a tron-trol panel stands an excellent chance of having a "white elephant"unloaded on him by a wholesaler who's been looking for an inexperiencedamateur to dump iL on.It is alright for a beginner to buy a control panel with a few,nece5sery control features built in, provided the dealer is willing toexplain the various wiring connections and any special requirenents atthe time of sale-- tnd provide additional information afterwardt i{needed. After the first installation has been completedl the novicewill have sufficient experience to evaluate the more sophigticated

control panels. Until thenq the simpler the better-t6


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BELLB & SIRENEE=E=-==-='=--E3E-E==-=E EBecause a burglar alarm bell will be perrnanently exposed to a var-iety of weather extremesr one should not consider using e bell which isnot "UL Listedr" meaning that its overall quality has been tested andfound acceptable by the Underruriters' Laboratories. (The UL label is agenerally reliable indication of quality where alarrn components are con-cerned' ) A burglar alarm bell should be contained in a heavy-gaugErrweather-resigtant , louvred cabinet, which should be equipp.i withtamper-detecting sr"litchesr crF',tamper switches. .,

The inset above shows a burglar alarm bell in a heavy-duty cabinet.Note that the gong is mounted on a removable plate, (called a 5uspEln-sion plate. ) The plate isolates the gong from the mounting surfacerhich otherwise lrould absorb' the g-ng's reEiclnance. The iuspensionplate is secured to internal brackets by machine screws, then the outerdoor is sealed by more screws. Renoving fine-threaded machine 5crewsis a time-consuming Procedure which, in combination with the measurelsoutlined below, provide an adequate level of protection for the mountedbell. Even when a bell cabinet is msunted high above street level,sotn! burglars won't hesitate to climb a ladder to get at it, providedthey can do so withsut being seen. The following descrihes how aproperly rrired bell will frustrate such a conprclmise attempt:Fig' 5-l {next page) shows a bell cabinet with the suspension plateand gong rernoved- Note the two tamper switches rnounted on the innerside of the cabinet, r*ith their plungers facing to the front and to theback' The ptunger of the front swititr protrudes through a hole in thesuspension plate, (when it is in place), and the ptunger of the rearswitch protrudes through a hole in the back of the cabinet. hlhen thecabinet is mounted'and sealed, the plungers of both switches are Ecrm-pressed by both the mounting surface and the closed cabinet door-Fig. 5-? is a close-uP view of the tamper switches (only) and howthey are wired- (The three holes cln each switch are for the mounting.screws. ) Note that a short, ZZ gauge iurper wire (A) extends from ascrew terminal of one switch to a terminal of the other switch, con-jgining both snitches Fy . series connection. B is a ZZ gauge pair,which is brought into the premises and connected to any rooi oi theprotective circuit-17


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Figurc 5-t Figurc 5-2(I+ convenient, this connection ,nay be made inside the controlpanel.) In effect, these switches represent a separate loop in theprotective circuit and they serve the same purposel as any of theswitches used inside the premiseg to protect windows and doorst etc.

Fig. 5-3 is a side-view of a bellcabinet, mounted and sealed. Even if aburglar removed the three screws thatseal the cover, the moment the cover isopened the plunger of the front switchwill release, opening the circuit andactivating the bell. The burglar stillwould not be able to reach the bell wir-i ng r+i thout f i rgt removi ng three morescrens that secure the suspension plate.Not an easy task while standing cln aladder with a 1OB decibel bell poundingartray in onEl's facet wondering i+ thepolitre are on the way.

Flsurr 5-5surface, the bell willenough to release the rearbe mounted as secunely asLikewise, i+ an attempt is made to prythe cabi net ar{ay f rom i ts mounti ngbe activated the moment the cabinet is priedtamper. For this reas;on, the cabinet shouldpos=ible.

An increasingly popular alternative to the traditional burglar alarmbell is the electronic siren, which is similar in its oscillating toneto the sirens used in police cars and other ernergency vehicleg.The electronic sirens uged {or burglar alarms consist o{ a PA speak-er contained in a protective cabinet, much like that of a bell cabinet'

I+ an electronic siren is used in place of a bell, it is recommendedthat a 12 volt model be used because of the relatively weak noise levelof the 6 volt versions.t8


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A typicat electronic siren speaker is shown above. The cabinet onthe right is tamper-protected in the seme manner as a bell cahinet.l"tost of these siren= employ a remote driver/amplif ierr a :ieparatenodule which is contained in the control panel. The nrodule is wired tothe bell terminals o# the control instrument, and the nires leading ttrthe siren are connected to the module- (Some control panels have built-in siren drivers. ) l.tost siren drivers can acccrmodate up to f our separ-ate speakers, which enables the use of multipll tnnuncittorl. (An"annunciator" is any type of noisemaker, a bell or a siren.)Bne technique which will greatly enhance the overall effect o{ eburglar alarm is to use an electronic siren inside the premisclsr inaddition to the exterior beII or siren. The noise generated by an in-door siren is deafening and will deprive a burglar of the ability tolisten for approaching danger. A convenient way to do this is by wir-ing a siren driver directly to any type of indoor FA speaker:ir or to apair of existing stereo sPeakers-Another useful actressory ig a strobe. The effect of a strobe burstin a darkened area is virtually blinding, causing general disorientat-ion and loss of balance. For outdoor application, weatherproof strobesare available for mounting directly onto betl or siren cabinets. Thegeare powered by the bell circuit and serve as a beacon for responding

pol i ce,Thus far it has been shown how adding modular accclssories to a basicburglar alarm control can ring a bell outside and a siren insidetswitch on outdoor or indoor lightingn temporarily blind a burglar witha strobe burst, 'visually guide responding police to the sound o{ anactive alarm arrnunciator, and automatically silence the annunciator(s)after a fixed period of time. The following sectictns are devoted tothe many seng,ors, {detectors and switches}, which may bc wired into theprotective circuit to initiate the foregoing effects. It is assumedthat the reader is sufficiently acquainted nith the operation of aburglar alarm system that no further digcussion of control functionswill be r=.===..y, If not, a review of the foregoing sections isrecorotnended before Proceeding further.19


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ITESTINE IIITH A IIETER

Working with burglar alarms calls {or the performance of certaintests to determine the factors of polarityt continuity and voltage.Fortunatelyr these tests are quite simple and each nay be performedwith an Elasy-to-use instrument called a ruftireter, or "meter" in thelanguage of the trade.There are hundreds of differe'nt types of multimeters availahle; ran-ging in price {rom twenty dollars to several hundred dollars. The moreexpensive rnodels are extremely accurate and are designed for sophisti-cated aPPlications. (Such precision is not required for testing burg-lar alarm circuits. ) Small r lightweight multimeters, which are ideal{or burglar alarm r+orkr are available from alarm equipment suppliersfor around thirty or forty dollars.Because of its highly technical appearance, e multirneter can beintimidating to the novice who has never used Eror. The face of themeter is graduated into hundreds of fine incrementg and there are manynumbered settings to select from. However, the device ig extremelysimple to use:A typical multi-meter is a rectangular device, with a pair of wireprobes extending frorn its body. It rnay be set to test either Atr or DCvoltage or electrical continuity through a "dead" conductor. Fecauseburglar alarros operate on DC, the only Atr test will be that of determ-ining whether a wall receptacle is live prior to plugging in a polrersupply transforrner. This is done by selecting the AC funetion and in-serting the probe tips into the receptacle. I+ the meter moveg, theoutlet ig live. If it doesn't arsve, the sutlet is dead. Aside fromthist the meter will be used exclusively {or DC and continuity testing:POLARITY:Polarity means the difference between the Positive (+) and theNegative (-) "sides" of a DC power source. It is important to knonwhich is which because Dtr components require that polarity be observedduring wiringr that is + ttr +t - to -. The terninals of most cclrnpon-ents are clearly marked with a + or symbol r trF by color. Red isPositiver black is Negative. Connecting a component the rtrong way(cross-poIar izingl., will cause damage, malfunction or non-{unction.It is simple to deterrnine the polarity of a Dtr powrr source! Theprobe wires of a multimeter are color-coded red and black. Theseprobes are applied to the terminals of the power scturce, (such as thoseof an unmarked battery Elr transf orrnEtr, ) If the needle of the meterswings to the right, (which is the normal direction), the terminal towhich the RED probe is applied is the POSITIVE side. If the needlemoves backwardr this roeans the RED probe is applied to the NEEATIVE

20


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side. A simple way to acquaint oneself with this test is to alternate-ly apply the probes of a multimeter to the terminals of any type ofbattery and note the direction in which the needle rntlves.

Froper polarity must be observed when connecting the ends of a pro-tective circuit to the terminalg of a control panel- Imagine that theprotective circuit battery is located a considerable distance away fromthe ctrntrol panel to which you are about to connect the protective cir-cuit pair. The polarity of the pair rnay be determined instantly byaPplying the meter's probes to the wire ends. If the needle snings tothe rightr then the conductor to which the RED probe is applied is PCIS-ITIVE. I+ the needle moves backward, the RED probe is applied to theNEGATIVE conductor. (The control panel tenminals will always be mark-edr either with the + and - symbolg or the colors red and black. )CONTINUITY!Eontinuity means the ability of a conductor, (a wire, etc, ), toaccomodate the flow of an electrical current. To perform this test,the meter is set to the position marked OHHS, (meaning resistance,)

Probcs Touching

Fieuru 6-lhlhen the meter's probes are brought together the needlc will sningall the way to the rightr indicating unimpeded continuity. By bringingthe probes together a circuit is completed, consisting of the probewirest the neter's battery, and an electromagnetic coil inside the rnet-elr that rocrves the needle.U the metet'= ptoUts are applied to any conductive rnediun, whetherthe shaft of a screwdriver or a I'OOO ft. protective circuit, theeffect will be the same. So long as there is unbroken continuitythroughout the conductor, the needle will indicate by swinging to theright.l+ the needle doesn't movc!, there is a break somewhere in thei

conductor.21


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(INTAcT)Circuit is intact - leter needle deflects to right

Fig. 6-2 shows aprobes of a meter,conductor is intact,uity, (no resistance

Flgurr 6-2conductor, (a pair o# wires open at one elnd.) The(A & B), are applied to the open ends. Because the(no breaks),' the aeter is indicating full contin-to the flow o{ electrical energy, )

(oPrN)Circuit is broken (at arror) ileter needle does not rove

Flgure 6-3In Fig. &-3 there ig a break (open) in the lower leg of the con-ductor. Note that the needle hasn't moved frorn its extreme leftpositionr showing that energy cannot flow through the circuit.Breakg in continuity are rarely visible. One example of a situationin which a concealed break would be impossible to locatc nithout theaid o{ a meter is an clpcln occurring beneath the insulation of a con-ductor. This can be the result of a manufacturing defect, excessivestrain when pulling wire through a tight space or careless use of astaple-gun while fastening the pair. The example seen in Fig. 6-sshows such a breakt it could be precisely located by advancing theprobes of the meter along the length of the conductor a few feet at atime. trontact with the wire under the insulation is nade hy pushing

map pins through the insulation and applying the neter probes to thepins. Ideallyt the tips o# the meter's probes will be alligator cliprinto which pins may be clamped.Burglar alarm wire is usually packaged on 5OO' spools. The wire iswound on the'spool so that both ends of the 5OO' pair are exptrsed andaccessible' By twisting the open conductors at one end of the spooltogether and applying a areter's probes to the other endg, the entire5OO'pair may be tested for a defect while stitl on the spool. It isreccttnmended that this test be performed on every spool of wlrc prior tousing it. Each spool is factory tested right after it's wound, butdamage could occur during shipping- It is rare that a broken conductorwill be {ound in a fresh spool of wire but, i+ one exists, it's best tofind it before the wire is installed-- especialty inside a wall !

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EENSORS

Ey now it should be clear that a burglar alarm is activated by soneaction which causes an oprr (break) to occur at rny point in the pro-tective circuit. The open may be produced by disconnecting an externalprotective circuit battery, rernoving either o{ the protective circuitconnectisns from Terminals 5 & 6 of the control panel r cutting a con-ductor or otherwine producing an opGn rnywhcrt elong thr lcngth of thrprotective circuit wiring.As explained in the secticrn on PRETECTIVE CIRtrUITS, a wide varietyof special devices ere situated at strategic locations within a Fro-tected premises and wired into the protective circuit. This variety ofdevices ranges from simple mechanical switches and {ragile conductors("lacing" wire and windsw "foil") to sophisticated electronic nrotiondetectorg such as passive infra-red, photoelectric, micro-wave, ultra-sonic, capacitance and audio-discriminator devicets. Regardless of howsimple sr complicated any of these devices might be they all serve thesame Furposet that of producing an open in the protective circuit whendisturbed by movementr oF excifed by the prennce o{ something apprclx-imate to a human form.Any device that is wired into a protective circuit to detect movr-nent or prasence when it is operated (as in the case of a switch) orcxcitedr (as in the cage o{ a motion detector}, is called a sensor.All sensoFs are connected into the protective circuit in the same man-nerf by cutting one leg of the protective circuit wiring, stripping thesevered ends and attaching thern to a pair of screw terminals on thedevi ce.The novice installer should not be intimidated by the complex natureof any type of motion detectsr apparatus. Like radios and tv sets, oneneedn't know what makes them tick in order to use them efficiently.All that the installer needs to know about an individual detector isits operational nature, its capabilities and limitationsr how to applyit and test it for proper operation. These procedures are covered in

the following segments.It is neither necessary nor practical for the installer to repair amotion detector device in the f ield, or othernise. I'lhen it is deter-mined that a detector is malfunctioning, the accepted practice is toremove it and retul'n it to the supplier for repair. The malfunction-ing device is then replaced with another of the same type. l+ a r!-placement is not immediately available, the wire ends from which thedevice is rernovrd are spliced together to restore the circuit until thedevice is returned. Excluding a detector from a protective circuit,even for one day, is not a desirable practice, Professional installersavoid this by making sure they have an adequate gtock of replacementcoroponents sn hand.?3


31/98

i

PLUNGER ShIITCH

trperationally, a plunger switch is no different from the spring-loaded button used to ring a doorbell, Pressing the button cltrsErs apair of internal contacts, completing a circuit, sausing the bell toring. lJhen pressure is releasedr the contacts release.

Flc. E-l Fis. 8-2The major difference between a plunger switch and a doorbell buttonis shape and internal construction. Ag seen in Fig. B-lt the push-button is a plunger that protrudes about 3/4" from the {ace (C} of theswitch. A relaxed spring is seen inside the body of the switch forcingthe plunger outwardr leaving the contacts clpen at B.Fig. E-2 shows the plunger compressed into the body of the switchtcollapsing the spring, causing a U-shapedl bronze jumper strip (D) to

complete a circuit across the internal contacts. A pair of Ecrer{terminals at A are seen as physical extensions of the internalcontacts, (B).The reader who is experienced in electrical wiring will probablyconsider the foreloing description of a sirnple device to be somewhattiresome, but this exhaustive explanation will be helpful to the novicein understanding how switches work and how they are used in a protect-ive circuit.So long as pressure is maintained against the plunger of this switchthe jumper strip remaing compressed against the contactst providingelectrical continuity through the switch via the externrl terminals.lrrlhen pressurc! is relaxed the jumper strip withdrawsr producing an openin the protective circuit. This will activate the alarrn.

II

et unlq r.Extended

24

Compressed


32/98

Although a Flunger switch is one of theof all sensors, there are many ways to useFig. B-3 shows the rnost cr:tntncln appli-cation: The ptunger switch is mounted ina 3/4" hole bored into a door-#rame- Theedge of the door will ctrrnpress the plun-ger when the door is closed. klhen thedoor is opened the plunger will release'

A pair of wires is seen attached tothe terminals of the switch and drawnthrough a small hole drilled through abaseboard. This pair will be connectedinto the protective circuit at the clos-est junction.

This wiring route Presumes an exposedwiring job. I+ concealed wiring is pre-{erred, (which is optional } t the wlringmay be snaked through the wall or tuckedbehind the baseboard. Fiq. E-$Another way to use a plunger snitch is to mount it in the bottomchannel of a double-hung window frane (and another in the top channel ti+ desired) and snake the wiring through the wall. t{hile this tech-nique provides absolute concealment, a special r weatherproof Plungerswitch must be used because of the direct exposure to moisture. Theweatherproof plunger is enclosed in a flexible rubber boot and thehouging of the switch is moigture-resistant-These are just two of ,nany possible applications of this versatileswitch, other possibilities are limited only by the installer's inagin-ation: For example, a plunger switch may be mounted in the surface ofa table or cabinet and the plunger cotnpressed by the weight of a valu-able itern of property. Removal of the item will release the plunger.This type of application is called a "trap" and is useful to ensurEr

that an alarrn will be activated even i+ a burglar toanages to bypass theperiseter sensors and gets ingide. Such a "trap" may be rigged andwired into the active "zone" of a dayfnigh* syster to guard againstrenoval o+ certain items from a premises during nornal business hours.The "tamper" slritch described in the section on BELLS & SIRENE issimply a plunger switch that is speci{icatly designed for surfacemounting inside a bell or siren cabinet. This type o{ plunger switchmay al=o Ue rnounted on the sill of tn outward-opening casement windowso the sash of the windon will compress the plunger when the window iscl osed.

simplest and least expensiveit.

iF1l1lttli.jrrl{

?5


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FIABNETIC 8I{ITCHt3-=E=E=E:EIEE--3I-t!aIt---!rEt-I-rItECA rnagnetic switch consists of two separate parts, the rwitch and themagnet. Except for a pair of strrew terminals on the switch, both partsare physically identical. one part is a short rod of permanent magnetsealed in a plastic enclclsure. The other part containr a clever rwitch-ing mechanism.

Inside the switch housing are a pair of contact EFms. one arm isstationary, the other is pivotal. The pivoting contact is held apartfrom the stationary contact by the light pulling +orce of a tiny,bronze', coil spring. The arm of the pivoting contict is made of fer-Fous metal t which is receptive to magnetic influencer. gJhen the magnetis brought into close Froximity with the switsh, its force outweighsthat of the coil spring and the pivoting arm is drawn sharply intocontact with the stationary arrn.The screw terrninalg on the switch housing are extensions of theinternal contact arms. lrlhen the two arrns are drarn together by themagnet's influencErr continuity is established between the rtrre$,terminals. lrlhen the dominating magnet is withdrawn, the force of thecoil spring is restored and the pivoting contact is putled away fromthe stationary contact.The operation of 'a rnagnetic switch may be observed by applying theprobes of a rneter, (set to read continuity), to the screw terminals ofthe switch tt9 observing the behavior of the needle: (See Fig. 9-1,next Page. ) t{hen the switch is separated from the magnet , li/4^ ormore) t its internal contacts remain oFen and there is no continuity,thus the needle will not move. When the magnet is brought ctose to thest*itch its internal contacts snap together ind the needfe swint- itr..p-ly to the ri9ht, indicating continuity betneen the screw terminals,

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Sritch - * Sritchllagnet *

f]]]- raonetFiq.9-l

Because of its clever, tno-part design, the magnetic switch iscompatible with a wide variety of applications, the most typical ofwhich are depicted in Fig. 9-2, below,

Flg. 9-2In Fig. 9-2, a series of five nagnetic switches are seen applied toa door and two windows. The switches are shown as Ar the magnets areB. The door switch is mounted on the door frame immediately over theupplr edge of the door. A magnet is mounted on the door directly be-neath the switchr holding the internal contacts closed and maintainingcontinuity through the switch.The windons represented in this diagran are the standard, double-

hung type. The switches art mounted on the window frarnes, the magnetsare mctunted on the sashes. ltlith the window switches and magnets ar-ranged as shownr normal novement of the upper and lower sashes isunobstructed.The magnetic switch described above is the surface-mcrunted type. Itmay be fastened to either a wood or metal surface with a pair o,J t/2"(*6) screws. The ideal spacing between magnet and switch ig L/8".l{hen the mounting surfaces for the magnet and switch are offset, makingit dif{icult to align the two segments, plastic spacers (and speciallydesigned brackets) are available to cornpensate for the offset distance-The plagtic spacers, (or "shims"), are l/8" thick and conform to themounting base shape of the magnet or switch- lrlhenever a rnagneticswitch is used crn a ferrous metal surfacer at least two spacers shouldbe used to move the magnet and switch farther away from the mounting

27


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sur+atre. otherwise the metarlic ,nass will absorb energymagnet and weaken its ef{ect on the switch. from theDther types of magnetic switches are available for special applic-ations. The shape and construction of these devices are dif{erent butthe same operating principle applies to each of them.< /,Item I is a sealed, cylindrical magnetic switch, which is L/4r, rlideX l-l/?" long. Instead of Ecrew terminals for connecting it into aprotective circuit, a pair of wire tajJs is provided for soldering tothe protective circuit wiring. ? is a bare (not sealed in plastic) rodof permanent magnet, which is the same size as the switch. S is aplastic mounting tab, curled at one end into a loop which accomodatesthe magnet or switch perfectly. On the back of tire tab is an adhesivecpad for convenient, stick-on mounting. This type of switch is commonlyused on horizontal sliding, aluminum-frame windows, (on which the rect-angular type described above cannot be used because of their shape andsize.) A cylindrical switch and a magnet are slipped into separatemounting tabs- The switch is gtuck to the frarne above or alongside thesliding window- A magnet is stuck to the edge of the window glass inalignment with the switch, The mounting surfaces should be cleanedwith alochol be{ore applying the tabs or the adhesive is likely to

fail.This type of magnetic switch is alscl appropriate for concealed atr-plications. One common example is that of boring a l/4', hole upthrough a doot--fratne, and another l/4" hole down l-t/Z" into the upperedge of the door. Both holes nust be carefully aligned. The switch isfitted into the hote in the frarne, with the wire tails extending upwardinto the hollow above the frame for connection to the protective'cir-cuit. The magne't is f itted into the hole in the door edge. lrlhen thedoor is closed the magnet is aligned end-to-end with the switch. Theforegoing arrangement also applies to wood-frame, double-hung windohrs,(both top & bottom), when a totally concealed installation isdesirable.A large, heavy-duty magnetic snitch set, both parts encased in castaluminutnr is available for protecting rotl-up garage and warehousedoors. This switch has a long pair of connectirrg *irei extending fromone endt protected.within a 24" length of f lexibl;, l/4,' alumir,,rn t,.,b-ing. The switch may be surface-mounted or set in poured concrete onthe floor just inside the door and alongside the frame, where the tubeis bent around the frame and upward along the inner wall. The wiretails are connected into the protective circuit. The magnet is attach-ed to the lower edge of the door immediately above the switch. lrlhenthe door is rolled down, the magnet engages the switch. This type ofswitch should not be used on -roll:tp doors which are loosely hung andsubject to movE6Ent, (from wind, vibration, uumping, .t.. I

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LEAF SI{ITCH

The feaf switch is named for the flexible strip (leaf spring) thatextends frorn one side, This device ig operationally similar to theplunger switch. It is equally inexpengive and very simple to use.The major difference between the leaf and the plunger switches isthat the leaf switch is surface mounted. Note that there are two pairso* mounting holes on the body which enable the (1" / *6, mountingscrews to be inserted either from the top or side of the device.Connection to the protective circuit is made via the pair of scFehtterminals seen on the front side of the device.The leaf switch is a quick, handy, inexpensive way to protect anytype of opening which is covered by a movable barrier, such rs a roofhatcht trap-doorr etc. The device is mounted cloge to the barrier sothat the lea{ is compressed hy the barrier when it is closed. Eompres-sion o{ the leaf engagesi a pair of internal contactg. Relaxing pres-sure against the leaf separates the internal contacts, triggering thealarm. r

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I.IERCURY 6T{ITCH

The principle of a mercury switch is expressed in the above diagramrSeen on the left is a laboratory +lask which is partially filled withmerrcuryr a highly conductive, heavy liquid substance. Two rigid wiresare Passed through the cork in the flask and extend donnward into themercury. The probes of a meter (set to read continuity) are attachedto the external ends of the two wires, indicating that the rnercury isconducting an electrical current between the two wires. On-6e rffghtthe flask is shown tilted to one sidel withdrawing one of the wiresfrom the conductive ncrrcury. As indicated by the zero continuityreading cln the meter {ace, the effect is identical to opening thecontacts of a switch.The portion of the wires inside the flask are regarded as internal

contactst the tips of the wires extending outside through the cork arethe exterior tertinajs. Thus there is no functional di{ference betweenthis ingenious device and any other switch. I'techanically, the mercuryswitch is operated by simply tilting it.l'tercury switches come in many shapes and sizes and are used in awide variety of apFlications, such as sxitching on the light in anautomobile trunk nhen the hatch is raised. Regardless of the shape ofits housingt inside every rnercury switch is a sealed glass vessel witha pair of contacts and a pair of terminals arranged egsentially theEiame as in the flask exaople seen above. In order to adjust thesensjtirityr or angle of activation of a otercury switch, the vesselitself is suspended cln some type of mounting bracket. The type ofmercury switch used in burglar alarms is represented belowr

A is theSCreul. mounting bracket. Bis30

the switch. Cis the adjustment


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After the bracket is fast-ened to the mounting surface,the probes of a meter are at-tached to the terminals of theswitch. The angle of theswitch is then adjusted to par-tially tilt the vessel. Theobjective is to cause activat-ion when the mounting surfaccis tilted two or three inchesin its opening direction.

A mercury srlitch may be ugedto monitor a hinged skylightcover, transom, cellar doorttrap doorsr ctF whatever applic-ation calls for this type ofsensclr. A special-purpose doorcord (C) is available with aflexible connecting cable and aterminal block attachedl forapplications like the one seenon the left:

This version enables theattachment of a foil pattern tothe terminals of the switch (A)which is mounted crn a transotn.The terminal block (B) ig fast-ened to the adjoining frame.The flexible cablet (called adoor cordl I enables free ncrve-ment of the transom when thealarm is not in use.

hlhen the alarm is switehedoftr disturbance of the foil Pat-tern or mcrvement of the trrnsomwill activate it.No sensors are shown on thedoor below the transom becrugsit is not relevant to this dig-cussion. Howeverr if a magnet-ic switch were usedt it couldbe connected in series with theprotective circuit connectionto the terminal block of thenGrrcury switcht (at B. )

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TRAPS

Although the cfrp trap goes back to the stone age of burglar alarntechnologYr it continues to afford a sirnplen inexpensive means of non-itoring a variety of situaticlnst such as ventilator openitrgsr windsw-mounted air conditioners, garage doors, etc.AI len+l IT B-M

The clip trap shown above consists of two parts: A is the pfug, Bis the jack. Eoth parts are seen in the center diagram with theirtrEtvers onf engaged as they would be in actual service. There are twodif{erent hrays to use a clip trapl oor is carled a ,, live trapr,' theother is a "dead trap. "

Protec t ive Ci rcui tFigure tZ-l

An example of a live trap is shown abover applied to the gritle of aventilator duct: Note that both legs of the protective circuit wiringare connected to the scre!{ terrninals of the jacx (B}, which is {astenedto the wall just below the duct. The continuation of the protectivecircuit is connected to the screh, terminals of the plug, (A). The pro-tective circuit wi.r'ing is securely {astened to the r+all at the pointsmarked X.hlhen A is plugged into B, the path of electrical continuity may beseen by examining the diagrams of both parts: The btades sectn protrud-ing downward from the plastic base of the clip are metallic extengionsof the terminal scrertls visible on top. The hooked posts in the centerof the jack ?re shaped strips of spring steel, spaced to hold theclip's blade firrnly when it is inserted.'

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It is not uncommon for aduct and cut through or kick12-1r i+ the grille is kickedjack. If the hurglar reachedef f ect would be the sarne,arrangement enables removalwithout need to disassemble a

burglar to wriggle through a ventilatorout the interior grille. As seen in Fig.out the clip witl be dislodged from thethrough with a tool to cut the wire thethus the name live trap. This clip trapof the grille for cleaning and maintenancemorc! permanent type of wiring.A typical use for the dead trap is that of a floor-level trip wire,which is use#ul in simple, "lohr risk" applications such as a tool shed,or the trip wire may be passed through a hole in a wall and stretchedacross an exterior driveway or path, enabling the outside of a premisesto be nonitored by an interior alarm system. The same type of cliptrap lnay be used for a dead trap, with two major differences in thewi ri ng:

In the above rxample, the jack (B) is wired in series into one legof the protective circuit (in the usual mannEr. ) The plug tA) is no.!used as a Live continuation of the protective circuit. Insteadt ashort jumper wire (C) is connected acro:rs its terminals to affectcontinuity when it is plugged into the jack. (Review the drawings ofthe two parts if this is not clear. )A length of fine, black fishing line, (at least 2O* test) t is at-tached to A and stretched at baseboard height, where it is fastened atan anchor point shown as X. Trip wires of this typet strategicallysituated within a darkened premises are a simple, efficient, economicalway to protect a low-risk premisrs.The floor-levef trip wire is but one! way to use a dead trap. An-other technique is to stretch the wire across a closed doorl tack it tothe lohrer sash of a window, or use it in any manner dictated by comnonsense and imagination. Its range of applications is limitlBSs.

IJot{0)IJoq)!ot]Ar

Any actionits jack willAny actionits jack-- orwill initiate which causes the plug of arevers thr suparvisod tripan alarm'

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which causes the plug of a dead trap to be withdrawn frominitiate an alarm.live trap to be withdrawn fromwiru (ag shown in Fig. 12-l)--


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VIBRATION DETECTOR

The vibration detector used in contenrporary burglar alarms is anadaptation o{ the "trenolo" switch, which was devised by the Britishcloak&daggerservice(duringWhl-II)fordetonatingvehiclebombginsabotage operations. hlhile the tremolo was designed to close a circuitupon sensing vibration, the burglar alarm version c'Pens a circuit'Thedeviceisapprox.thesizeofpackofchewinggu'll.on the le#t are side and front viewg of a typical vib-ration detector, (with its trover removed. ) A is thependufur, a smalI, cylindrical brass weight fastened to" tf,in strip t:+ spring bronze' B is a pair of terminalscrews. The base of the device i5 non-conductive plas*tic. Note that another thin strip of bronze extendsfrom the lower terminal screH, upward and under thep=,.d.,I.,'. Not shown in this diagram ig a gengitivityadjustment screw, which adjusts the spacing between thrgpendulum and the bronze strip beneath it'

The device is fastened to a solid, vibration-frFe surfacer (e.9. abrick wall), which might be penetrated by extremely forceful tneanstsuch as hammer-blows, orirling, etc. (Breaking through cellar wallsr ofadjoining commercial pre6ise5 is not an urrcommon entry method when thestakes are high enough. ) It may be {astened with screws but epc'xyiement provides a better union with the mounting surface'After the device is fastened, the probes of a meter are apPlied toits terminal screwg and the sensitivity adjustment Eicreu| is slswlyrotated cl0ckruise until the meter indicates closed contact between thependulum and the conductive strip beneath it, by swinging fully to theright. The adjustment screw is then backed of# until the meter needledrops back, i.naicating loss of contact. Then, by alternately poundingon the mounting surface and re-adjusting the sensitivity srcrertlt thedevice is,,tunei" to detect a forceful attack on the protected wall'bJhen using a meter (set to read continuity) the proper indicationwill occur as a slight bounce o{ the needle, not a fixedl wide movementto the right

"=o.c,rts r*ith a solidly closEd circuit' A sharp blon

'against the mounting surface (within a 12' radius) should cause theneedle to movEl sfitfrtfy and fall back. Keep in rnind that a protectivecircuit relay is extremely "fast" and sensitive, and will rerct to theslightest disturbance in the flon of supervisory current through it;therefore the slightest fluctuation of the meter needle rePresents asufficient disturb'ance to trigger the alarn'Eonsider that a blow struck while testing the device will not be as5,evere as would be those struck in an actual attack on the nall t so thedifference must be experimentally projected' Be careful not to adjustthe sensitivity too high t 07 false alarms will result from such routineevents as thunderstorms, passing trucks, etc. hlhen the sensitivity isproperly adjusted, connect the prot=clive circuit to the terminalg andscre$, the cover on the gevice. (Not too tightly, or the sensitivityadjustment might be altered. ) 34

J+

h AB

lll


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LACINGtB=E!t=tttEEMEIGII I=I-tt--I---3

hlire facing is a very sirnple $tay to monitor a door or window that isnever usedt a weak section of wall, a workshop skytight and situationswhere the use of switching sensors, (magnetics, rt.. l, is neithernetressary nor practical -

Lacing is simply a continuous pattern of fine, brittle r*ire, (eitherbare or in=ulated), which is fastened in an even pattern across the op-ening or barrier to be monitored' The door shown above operns inwardand is fitted with three panels, any of which could easily be kicked inby a burglar- It is situated in an area lrhere appearances are not animportant contrernr Scr lacing is the ideal sensor for it.The pattern was cFeated by driving ordinary carpet tacks into the

dosr-frame on both sides of the door at 2" vertical intervals. Thetacks are driven in only partially, leaving about !/g,, extended to wrapthe lacing wire around the heads. Begin forming the pattern by wrap-ping about four turns around the {irst tack, leaving a short tail hang-ing to splice into the protective circuit. Then stretch the lacingr+ire acr(]ss to the corresponding tack and wind four turns around it.l"love the wire down to the tack below the one just wound, wind anotherfour turns and stretch across the door again. Repeat the Frocess untilthe pattern is completed, leaving another tail hanging at the lasttackt then gently drive the tacks almost flush with the wall. (A hardhammer blow r"litl easily break tne wI?EI- Splice the pattern into theprotective circuit as shown and the job is finished.hrhile a lacing pattern is easy to by-pass, (by attaching a jumper tothe strands at the top and bottom), access to the pattern would be nec-essary- To penetrate this pattern without breaking any strands wouldrequire careful, skillful cutting of the door, which only a sophisti-cated thief is capable of. This type of sensor is not recornmended forany type o{ high-risk application, however it is adffiate for protect-ing against the averager unsophisticated, ',crowbar', burglar.Lacing patterns are! useful for nonitoring potentiat points of force-ful entry onto low or average-risk prernises such as {iimsy, adjoiningwalls, unused doors, windows and skylights, etc.Ventilator ducts are cornmonly protected by fastening(next page) over the interior grille. a laced frane

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A laced frame is easily constructed from two sections of wt:od {rame(of optional shape and size) which are made from l" x !/2" strips.Thumb tacks are uged to stretch the lacing onto one of the frame sec-tions. lrlhen the pattern is completed, the second section is appliedover the first (leaving the two connecting tails hanging out), a holeis drilled through each corner of the frame and it is fastened over theventilator grille. Againt this type of senstrr should be used only whenthe maximum level o{ attack sophistication is that of a burglar squeez-ing through the vent and kicking out the gritle-- breaking the lacingstrands at the same time. (This diagram showg the completed fl-ame, notthe unfinished sections. )l"lore sophisticated versions of laced screenq are available, made toorder according to size. One type is a finely-crafted window screrenthat looks ns different from ordinary screen but has insulated lacingwire woven into the screen material. Because the cutting or remtrval o{window screEns is an extremely cornmon practice in regidential burglar-ies, screens of this type are uniquely efficient periroeter msnitoringdevices. They, will activate the alarro if the screen is cut or removed.Also available from commercial suppliers are pre-assembled screenswhich are rnade {rom basswood dorrels that have the lacing wire imbeddedin them. The wiring of these screens incorporateg both legs of theprotective ci,rcuit rather than just one, as a measure of protectionagainst 'by-pass' by the jumper method mentioned abtrve. This techniquepresents the burglar with a random arrangement of strands, some ofnhich are extensions of the + (positive) leg o{ the protective circuitand sone of which a;e extensions of the - (negative) leg, rf a jumperis attached to a positive rnd a negative strand, the protective circuitwill be shorted at that point and the alarm will be activated. ($eethe section on SH0RT trrRcurTs if this princitrle is not crear.)The wire used for lacing is available fron specialized suppliers andis designated as hard-drasrn ctlpper wire. This type of wire is especial-ly suitable {or lacing because of its brittle, non-re=ilient nature.

It will not stretch as will normal copper urire but will break easily i+stress is applied to it,36


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BhIITCH ]'IAT

Switch mat is available in rolls of 1O to 25 +t. long x 30" wide andmay be cut to any desired length for placement under carpeting. Themat is made up of individual strips, arranged one next to another andsealed r*ithin a thin, plastic cover. Each strip is an individual sen-scf,r, consisting of two metallic strips which are held apart by a resil-ient, insulative material. lrlhen the mat is compressed the two metallicstrips are farced into contact, which closea a circuit. A wire tailextends from each metallic strip. When the mat is intact, the wiretails serve to conjoin the separate strip segments. The full-lengthnat may be placed beneath a carpetr oF it may be cut up into individualsegments (stripsi which rnay be distributed ovErr a wider area. Eachsectisn (individual strip) cut from a mat has it's own wire tails forattachment into a protective circuit, Bo a full size mat will yieldseveral smaller sections Er a large number of individual strips.

PF: DT EC T T t/E t: RCLJ TEecause of the simple nature of gwitch rnat congtruction, whicharnounts te several pairs o{ metal contacts (strips} held apart by thinspringy material, it maintains an open circuit until conpressed, (by afootstepn etc. ) Because a sensor which maintains optn contrtrtr cannotbe series connected into a protective circuit, a device called a ratconverter must be used. A mat converter contains a simple circuit thatreverses this status, presenting a clond trgntact status to the protec-tive circuit until the mat is compressed-- at which point the convertershows crpen contact status. An alternative to using a mat converter isseen below: The rnat ig wired directly to the protective circuit inparallel (compare the connections in both diagrarns) so that closure ofthe rnat's contactg irnposes a rhort circuit. blhen this wiring method isused, the protective circuit battery cannot be wired as shown in Fig. 3-I, in SHtrRT CIRtrUITS. Review the section on SHURT CIRCUITS i+ thisprinciple is not clear.

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rl ll rL |t tt tl tl tl lr tl rltl tlrl rl rl rl rl tl lt rl rltl tl rl tl tl tl tl rl lr rl tttl tl tl rl rl tl tl rl lr rl rlrl tl tl rl rl tl tl tl lt rl tttt tr rt tt tt tt tt tl ll tl tltl rl tl rl rl rl tl rl lr rl rl


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PROTECTINB BLABSr-tr-tarr-t-lralll:--llt-rr-r'lrr!l'lttrlA number of imaginative moviEr =iequences have created the notion thatplate glass is easily penetrated by scratching it with a glass-cutterand removing the scored section with a (suction-cup) glazier's handle.lJhile this is a very good trick for the crovies, it is virtuallyimpossible to penetrate a mounted glass Pane in this manner! Theprop", use of a glass cutter calls for an experienced hand and rigidsupport directly Uitrina the section being scribed. Once the pane is,.ribed, it rnusi EEGarply tapped {rom the opposite side to effect aclean separation.Burglars do not use cutters on glass. They either remcrve the entirepane b! prying away the moldings that hold it in ptacet or they smash

it out! Befoie smashing a glass panGlr a sophisticated burglar willcover it with wide gtrips of duct tape to minimize shattering, and sup-press the noise with several thicknesses of soaked nellsPaPer. There-fore one should never be confident that the factor of noise will dis-courage a burglar from breaking glassr espelcially a smaller pane, togain entrY.An efficient method of protecting glass is to apply a continuousstrand of conductive foil ribbon around the edges of a Pane on theintrrior side, and connect the ends of the strand into a protectivecircuit. If the pane is shattered, the {oil conductor (which is theequivalent o{ a strand of fragile wire) will be torn, interrupting theflow of current through the protective circuit-- which triggers the

al arm.Applying feil to glass is a simple procedure but making a neat jobo{ it requires sooie practice. By experimentally applying a foil pat-tern to a small pane of glasa, then scraping it off and doing it overtthe technique may be mastered in a few hours. The follovring is a listof the item:i required, along with a description of the technique {orapplying foil to window PanErs.1>

2>

Foitl comes packed on 1 rb. rolls of 3/8" wide ribbon. Aroll contains several hundred feet, which is enough fordozen= of large windows.Fotl Dirprngrr The most convenient way to work with {oilis to suspend the roll above the working surfatre =itr the rib-bon may be drawn downward as it is applied. This keeps itout of the rray and prevents tangling. A special dispenser ismade for this PurFgl:;e. It is simply a pair of flat discsthat clanp onto the roll and are held in place by a screl{-clnknsb. A bracket extends from the tlne digc for hanging thedispenser on a nail. (If a disPenser is not available theroll of {oil nray be hung g1n a loop wire or heavy string-)

Varnish, Thinner and Brughr t}'dinary white varnish isused as both adhegive and sealer- (A small can is plenty' )Also, a can of benzene or a similar thinning agent will be3>

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4.)

ELdJ

6>

needed, along r*ith a short, wide-mouth jar. (A snall t cleanpeanut-hutter jar is ideal.) An ordinaryr 3/8" flat-tipartist's brush is used to apply the varnish.squeegeet A very handy item to use as a squeegee forsmoothing +oil ribbon to a glass surface is a Rubbermaiddishwashing scraPer, with the handle cut off. (Bne that'sbeen used and goftened by hot water won't work very well-)If this itern is not available, the shoutder of a matchbookcover may be used.Tailor't trhalk and l'larking &ridrr An ordinary piece of(white or yellowl tailor'5 chalk is perfect for marking aguide-line around the edges of a glasg' Pane. The guide linesare marked on the ou-tside of the glass and are used to alignthe pattern as the foif-s apptied on the insi4e. The guide-lines are marked by running oner edge of a rigidr 5'quare guidealongside the edges of the window frame while holding thechalk against the opposite edge of the guide. An ideal mark-ing guide is a 2-Lf2" square block of wood for a small win-dow, t]r a 5-1/2,' block {or a large window. In a pincht adeck of playing cards ctr a cigarette box rnay be used.splicing Toolr blhen an applied strip o{ foil is torn arscratched it is easily repaired by splicingr oF aFplying apatch that overlaps the separated ends. lrlhen a splice or apatch is completed, it is necessary to puncture several holestnrough the overlapping ends of the patch or splice. A spec-

ial tool is available for this purposei it is a small, multi-toothed disc, mounted like a wheel on a pencil-size handle'This tool looks very much like a miniaturized version of thegadget used to cut a Pizza into sectionsr but instead of aiutting edge the blade has pointed teeth: Instead of cut-ting, the wtreet's teeth penetrate the over-lapped sections.r*ry neatly and efficiently. If this tool is not availableany'type of pin may be used. (No less than a dozen holesshould be punched through each overlap. )

FOIL DISPENSERA short steP-ladder is usuallY

BRUSHneeded to Provide

SPLICINBTOOLa comfortable

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hrgrking Fosition through the separate stages of the foiling procedure.I+ the roll of foil cannot be suspended and centered over the workingsurface, it should be hung either on the belt or on a hook screwed intothe edge of the ladder shelf'

Be{ore beginning, fill the wide-mouth jar halfway with thinner' Theglass mugt be cfeanr and the areas to be fsiled should be wiped with de-natured alcohsl. or mineral spirits to reoove any oily film.

Above is an illustration of a finished foil pattern applied to apane of glass r*hich might be a picture window in a living room or aplate glass window in a commercial premises. Note that the patternbegins at I and. progresses through a seguelnce of six, right-angle cor-ner bends. In this example the pattern is terminated at the uppercenter o{ the window, which does not imPly a gtandard or a rule: Afoil pattern rnay be terminated rnynhrru on the window. The determining{actors are appearance and wiring convenience-The {otlowing page shons a numbered sequence of tha steps involvedin applying a {oil pattern to a

63945982 Tricks of the Burglar Alarm Trade PALADIN PRESS

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Transcript of 63945982 Tricks of the Burglar Alarm Trade PALADIN PRESS