hrb 4 electrical 2012 8.5x10.875 - carson dunlop

Electrical

ELECTRICAL

The home RefeRence Book ©

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Electricity has become an important element of every North American home. It provides lighting, heating and power for electric motors and electronics such as controls and computers. Our homes would not be nearly as comfortable or as convenient without electricity.

On the other hand, electricity is dangerous. It has to be installed and used properly to be safe. Electricity is tricky because it is invisible, it is complicated and it can kill.

InTRoduCTIon

1.0TheBasics

dESCRIPTIon Electricitycanprovideuswithheat,lightandpowerasinvisibleelectronsmoveinacircuitthrough wires and appliances. We can control whether it gives off mostly light or mostlyheatbyusinglightbulbsorelectricheaters.Electricitycanalsodriveelectricmotorswithfastchangingmagneticfields.

Wheredoeselectricitycomefrom?

Electricity is provided by utilities. It can be generated by moving water (e.g. Niagara Fallsgenerates hydroelectric power) burning fossil fuels like coal or from nuclear reactions, forexample.Aswelookformoreenvironmentallysensitivewaystogenerateelectricity,solar,windandgeothermalpowersourcesarebecomingmorecommon.Batteriesmaybeusedtostoreanddeliverpower.

Electricity is distributed through communities by a grid of overhead and/or undergroundwires. Electricity can be alternating current or direct current. Our discussion will focus onalternatingcurrent,sincethat’swhatwefindinhomes.

Let’sstartwithabriefdescriptionoffourcommonelectricalterms:V=Voltage,measuredinvolts.Thisrepresentstheelectricalforcethatisavailable.I=Current,measuredinamps(amperes).Thisrepresentstheamountofelectricityflowing.R=Resistance,measuredinohms.Thisisameasureoftheoppositiontoelectricalflow.P=Power,measured inwatts (1kilowatt is 1000watts).This representstherateatwhich

workisdone.

Thetablebelowshowstherelationshipbetweenthesefourterms.

Table1–ElectricalBasics

V=Voltage(volts) P=Power(watts) I=Current(amps) R=Resistance(ohms)

Formulas: V=IR P=VI

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1.1Voltage

dESCRIPTIon Electricityflowsbecausethereisapressure(volts)beingappliedtoacircuit,suppliedfromthelocalutility.Utilitiesprovide240voltstohomes,intwo120-voltbundles.

1.2Current

dESCRIPTIon Theelectriccurrent inacircuit,measuredinamps(oramperes),istherateofflowofelectricitythat results when a light bulb,heater or appliance is turnedon. The amount of current is aresult of the amount of pres-sure (volts) and the resistanceto flow (ohms). The larger thepressure, the greater the flow.The larger the resistance, thesmallertheflow.

ConTRoLLIngThE Two dangerous things can goFLoW wrongwiththeflowofelectricity:

1. Too much flow results inoverheating and possiblyafire.Wecangettoomuchelectricityflowing iftoomanyappliancesareplugged intoonecircuit.Thereareotherwaystoomuchelectricitycanflow,butlet’sleaveitatthat.Ifeverything works properly, fuses and circuit breakers turn the electricity off when toomuchelectricityflows.

2. Electricitymayflowwhereitisnotsupposedto.Thisiswherepeoplegetelectricalshocks.Ithappenswhenyoudropthehairdryerorradiointothebathtub,youstickakeyintoanelectricaloutlet,oryoudriveanailintoaliveelectricalwire,forexample.Aflowoflessthanoneampcankillyou.

1.3Resistance

dESCRIPTIon Resistance,measuredinohms,preventselectricityfromflowing.Weuseresistancetocon-trolwhetherelectricityflows,andifso,howmuch.Thingsthatslowdownorresistelectricalflowarecalledresistorsor insulators.Thingsthatallowelectricitytofloweasilyarecalledconductors.

ConduCToRS Goodelectricalconductorshaverelativelylowresistance.Conductorsareusefulformovingelectricityfromoneplacetoanother.Mostmetalsincludingcopperandaluminumwiringaregoodconductors.Aluminumisnotquiteasgoodascopper,butislessexpensive.Waterisaverygoodconductor,whichiswhyit’sdangerous.Whenelectricitycontactswater,itoftenflowswhereitshouldn’t.Thehumanbodyisaprettygoodconductor,whichisunfortunateforus.


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InSuLAToRShAVE Whenwedon’twantelectricitytoflow,weusethingswithlotsofresistance.ThesethingshIghRESISTAnCE arecalledinsulators.Air,glass,wood,rubberandmostplasticsaregoodinsulators.Homes

usecopperwire(aconductor)tomoveelectricityaround.Wewrapthewireinaplasticinsula-tor,sotheelectricitystayswithinthewire,makingitsafetotouch.

1.4Power

dESCRIPTIon Powerismeasuredinwattsorkilowatts(1000watts),andiscalculatedbymultiplyingthevoltage(volts)timesthecurrent(amps).Ahousewitha240-voltpowersupplyand100ampmain fuses has 24,000 watts. This is commonly referred to as 24 kilowatts (because onekilowattis1000watts).A1200-watthairdryerpluggedintoa120-voltcircuitwillresultina10-ampelectricalcurrentflow.

kILoWATT-houRS 1kilowatt(kW)is1000watts(W).Electricalconsumptioninyourhomeismeasuredinkilowatt-hours(kWh).Ifyouuse1000watts(1kilowatt)foronehour,youconsumeonekilowatt-hour(kWh).This ishowwebuyelectricity fromtheutility.Theelectricmeter recordskilowatt-hoursusedinthehouse.IfeachkWhcoststencentsandweuse500kWhinamonth,ourelectricalbillforthatmonthis$50.

nExTSTEPS Let’shaveaquicklookatwiresize,fusesandcircuitbreakersbeforewestarttolookatthehousesysteminmoredetail.

1.5WireSize(gauge)

dESCRIPTIon We use wires to move electricity around the house because wires are good conductors.The amount of current (amps) a wire can safely carry is determined largely by itsdiameter. A larger wire cancarry more current. Typicalhouseholdcircuitsaredesignedto carry 15 amps, and 14-gaugecopper wire will do this safely.Theillustrationshowscommonwiresizesandthetypicalsizeoffuse or breaker that is used toprotectthem.Aluminumisnotasgoodaconductorofelectric-ity, and a larger wire has to beusedtocarrythesameamountofelectricityascopper.It’sveryconfusing,becauselargerwireshave a smaller number gauge.Wethinkelectriciansdothistomakeithardforus.

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1.6BreakersandFuses

dESCRIPTIon Whentoomuchelectricityflows,thingscanoverheatandwemighthaveafire.Fusesandcircuitbreakersturnofftheelectricitywhenthereistoomuchflow.Theyarethelifeguardsoftheelectricalsystem.Let’slookatanormalhouseholdcircuit.

A 14-gauge wire with 120-voltpressurecansafelycarryabout15 amps before things get toohot.Weputafuseorbreakeratthe beginning of the circuit toshutthecircuitoffifmorethan15 amps flow. A 1200-watt hairdryerwillcauseabout10ampstoflow. Ifwepluga1200-wattcurling iron into the same cir-cuit,another10ampswillflow.Nowwehave20ampsflowingandthewireisgoingtogettoohot. That’s when the circuitbreaker should trip or the fuseshould blow. Losing power is anuisance,butitpreventsafire.

oVERCuRREnT Thefancynameforcircuitbreakersandfusesisovercurrentprotectiondevices.BothfusesPRoTECTIon andbreakersperformthefunctionequallywell.Acircuitbreakercanbeturnedbackonlike

dEVICES aswitchaftertheoverloadsituationiscorrected.Afuse‘blows’andhastobereplaced.Mostmodernelectricalworkinhomesusescircuitbreakers.

nExTSTEPS Fortherestofthissection,we’lllookatelectricityinthehome.We’llstartwithhowelectricitygetsintothehouseandspendsometimeonthepanelbeforelookingatthewirecarryingelectricitythroughthehouse.We’llfinishwiththeswitches,lightfixtures,junctionboxesandelectricalreceptaclesattheendofthecircuit.

Somepeoplethinkofelectricityasatree.Thetrunkisthebundleofelectricitycomingintothehousefromtheutility.Thetrunkissplitintobranchesatthepanel.Youcanthinkofeachcircuitinthehomeasatreebranch.Eachcircuittypicallyhassomelights,switchesandrecep-tacles.Youcanthinkoftheseasthetwigsoneachbranch.


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2.0ServiceEntrance

2.1ServicedropandLaterals:gettingElectricitytothehouse

dESCRIPTIon– Atypicalhousehas240-volts,broughtinthroughoverhead(servicedrop)orundergroundSERVICEdRoP wires (service laterals) fromtheutility.Thereare threewires.The liveblackandredwires

AndSERVICE eachbring120voltstothehome,andthewhitewireisneutral.ItdoesnotbringanyvoltageLATERALS tothehome,butcompletesthecircuit.

Thesewiresmaybecopperoraluminum.Thepotentialbetweentheblackandwhitewiresis120volts,betweentheredandwhiteis120volts,andbetweentheblackandredis240volts.(Incidentally,the“red”wireoftenhasblacksheathing,justtomakethingsconfusing).Thesizeoftheserviceentrancecabledetermineshowmuchelectricityisavailabletothehouse.

Theservicedropandservicelateralsaretypicallytheresponsibilityoftheutility.Everythingbeyond this point is the responsibility of the homeowner. Service drops connect to theservice entrance conductors, which are typically in conduit running down the outside ofthebuilding.

Undergroundservicewires(laterals)areinconduit,typicallyburiedtwotothreefeetdeep.Theconduitcomesuptotheelectricmeterontheoutsideofthebuilding.Fromtheelectricmeter,theconduitgoesintothebuilding.

Overheadservicedropsmaybeattachedtothesideofthebuilding,andcomedowntotheelectricmeterinaconduit(orcable),againalongtheoutsideofthebuilding.Onshorterbuild-ings,theysometimescomeinabovetherooflineandenteranelectricalmastthatsticksupabovetheroof.Thewiresgointothemast,whichformsaconduit,againrunningdowntheoutsideofthebuilding.

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120-VoLTAnd Typicalhouseholdcircuitsare120-volt.Some120-voltcircuitsuseablackwireandwhitewire. 240-VoLT Theothersusearedwireandawhitewire.Largeappliancesthatneedlotsofelectricity,like CIRCuITS stoves,clothesdryers,waterheatersandairconditioners,use240-voltcircuits.Theyusea

blackwire,aredwireandawhitewire,typically.

SERVICESIzE Thesizeoftheelectricalservicetothehouse(100amps,200amps,etc.)isdeterminedbythesizeofthewirescomingtothehouse.We’lltalkmoreaboutthisshortly.

CommonProblemswithServiceDropsandServiceLaterals

Whatcangowrongaswebringelectricitytothehouse?Therearethreecommonproblems–damage,improperlocation,andmoistureproblems.Wewillfocusontheoverheadwires,becausethere’snotmuchwecanseeofundergroundwiringcomingintothehouse.Remem-ber,problemswiththeservicedropareusuallytheresponsibilityoftheutility.

dAmAgEdWIRE Wirecanbedamagedbytreebranchesormaydeteriorateduetoweathering.Wheredamagesuchasfrayedinsulationisnoted,theutility(electriccompany)shouldbenotified.

CLEARAnCE Wiresthataretoolowcanbehitbyvehicles.Youdon’twantyourmovingtrucktakingoutyour electrical service before you move into the house. Overhead wires should be about12feetabovegroundlevel.Wedon’twantpeopleleaningoutwindowsorstandingondeckstobeabletotouchtheseoverheadwires.Wiresshouldbekeptatleastthreefeetawayfromwindows, and roughly ten feet above decks. Again, where clearance is not adequate, theutilityshouldbenotified.

WATER Waterontheoverheadwiresisnotaproblem.However,oncethewatergetsintotheconduitthatgoesintothehome,itisaproblem.

PooR Theservicedropwiresmaynotbewell-connectedtotheserviceentranceconductors.This ConnECTIonTo caninterferewiththehouseelectricalserviceandcreateadangeroussituation. SERVICE EnTRAnCE ConduCToRS

2.2ServiceEntranceConductors

dESCRIPTIon Theoverheadservicedropistypicallytheresponsibilityoftheutility.Thesewiresconnecttotheserviceentranceconductors,whicharetheresponsibilityofthehomeowner.Thishand-offpointfromtheutilitywirestothehomeownerwiresissometimescalledtheservicepoint.Theserviceentranceconductorsaretypicallyinametalorplasticconduitthatrunsdowntheoutsideofthehouse.Theconduitprotectsthewiresfrommechanicaldamageandmoisture.Somehomeshaveaserviceentrancecableratherthanaconduit.

dRIPLooP Adriplooppreventswaterenteringtheserviceconduit.Theservicewiresformaloopbelowtheservicehead,whichallowswatertodripoffthewire.Thatkeepsthewateroutoftheconduit.


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ConnECTIonTo Remembertheservicedrophastobeatleast12feetabovetheground.Ontallbuildings,theBuILdIng serviceisconnectedtothesideofthebuilding.Theserviceentranceconductorsformadrip

loopandthenenteraconduitthatrunsdownthesideofthebuilding.Onshorterbuildings,thedrip loopattachestoaser-vicemast(conduit)thatextendsabove the roof and carries theservice entrance conductorsdown along the outside of thebuilding.

mETERS The service conduit carries theservice entrance conductorsthrough the electric meter sowe can pay for our electricity.Metersaretypicallyontheout-side of the home close to thefrontofthebuildingtofacilitatemeter reading by a utility rep-resentative. Modern systemsare eliminating the need for ahumanmeterreader.

InSIdEBuILdIng Onceinsidethebuilding,theconduitmustbekeptasshortaspossible,ideallygoingstraightintothebox.Thisavoidsexposingtheconduittomechanicaldamage.

CommonProblemswiththeServiceEntranceConductors

dRIPLooP Sometimesthedrip loop ismissingordoesnotcreatea lowspotforwatertorunoff themISSIng/ service entrance wires. This results in water getting into the conduit, which can run into

InEFFECTIVE theserviceboxorpanelinsidethehouse,causingrustandpoorelectricalconnections.

SERVICECAPnoT The service entrance conductors have to enter the conduit through a weather-tight cap.WATERPRooF Watercancauserustandpoorconnections.Wherethereisevidenceofwaterpenetration,

repairsshouldbemade.

mASTdAmAgEd/ Theservicemastabovetheroofhastobewellsecuredandfreefromrustorrot.WeaknessesTooShoRT/PooR hereshouldbecorrectedpromptlytomaintaintheintegrityoftheelectricalservicedropand

LoCATIon serviceconductors.Themastshouldbetallenough(atleastthreefeettypically)tokeepthewiresclearoftheroof,sotheywillnotinterferewithre-roofingormaintenanceactivities.Wealsotrytoavoidhavingoverheadwiresrunningacrossroofs.Wedon’twantsomeoneupontheroofcleaningtheguttersorrepairingaleaktotouchthesewires.

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PooRFLAShIng Wherethemastpenetratestheroofsurface,theopeningshouldbeprotectedwithaflashing ATRooF thatpreventswatergettingintotheroofstructure.Wherethisisnoteffective,theremaybe

waterdamagetothebuilding.

dAmAgEd/ Theconduitshouldbeintactandwellsecuredtothebuilding.Rust,cracks,looseconnections PooRLySECuREd anddeformitiesintheconduitshouldbecorrected.

CoVEREdBy The service mast or conduit should not be covered by siding, so it will not be damaged SIdIng inadvertentlyandsoitcanbeinspectedeasily.

PooRSEALAT Theconduitshouldbesealedatthemeterandwhereitpassesthroughthewalltoprevent mETER/WALL waterpenetration.

2.3ServiceSize

dESCRIPTIon Theservicesizeisdeterminedbythesizeofthewirecomingfromthestreettothehome.It’softenhardtodeterminethewiresize,sinceitisinaconduit.Thesizeofthemainfusesorbreakersisagoodindicationofservicesize.

Asthepowerentersthehouse,itgoesintoaservicebox,whichhastwofusesortwocircuitbreakers(oronebigbreaker).Oneisfortheblackwireandoneisforthered.Nobreakerorfuseisusedontheneutralwire.Thesizeofthefusesorbreakersshouldmatchthewirecapacity.(100amps,200amps,etc.)SeeTable2belowforratingsofvariousserviceentrancewires.

Aserviceboxwithfusesmighthavetwo100-ampfuses.Thisindicatesa100-ampservice,not200amps.Youcan’taddthemtogether.Oneofthefusesprotectstheblackwireandtheotheroneprotectstheredwire.

Theratingstampedonthemeterboxorontheserviceboxisnotalwaysagoodindicatoroftheelectricalservicesize.

hoWmuCh Everyhousegets240volts.Theamountofelectricityavailableisdescribedbythenumberof ELECTRICITyIS ampsthesystemcansafelydeliver.100ampsisacommonelectricalserviceforanaverage Enough? home.Largerhousesorhouseswithbigelectricaldemandslikeelectricheatmighthave150

or200ampservices.Thelargestresidentialelectricalservicewetypicallyseeis400amps.Someolderhomeshave60-ampservices.Whilethismaybeserviceableforsomehomesandlifestyles,100ampsiscommonlyconsideredaminimum.

Table2–TypicalServiceEntranceSizes

minimumWireSize ServiceSize minimumWireSize uSA (amps) Canada

Copper Aluminum Copper Aluminum 4 2 100 3 2

2 1/0 125 2 2/0(1/0)

1/0 2/0 150 1/0 3/0

2/0 4/0 200 3/0 250MCM

Note:Variationsarepossible,dependingontypeofwire,temperaturerating,etc.


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Table3 indicateswhattypicalelectricalappliancesneedtooperate.Thesizeoftheserviceneededforthehousedependsonthenumberofelectricalappliances.Someoftheappliancesthatcantaxanelectricalserviceincludeelectricheaters,saunas,andhottubs.Itisthesimul-taneoususeofappliancesthatcausesproblems,andthis isdependenton lifestyle.Largerfamiliesarelikelytousemoreelectricityatthesametime,andmayneedalargerelectricalservicethanasmallerfamilyinthesamehouse.

Table3–TypicalPowerandCurrentforhouseholdAppliances

Watts Amps

Stoveandoven 9600 40

Clothesdryer 5000 20

Centralairconditioner 5000 20

Electricwaterheater 3000 12.5

Kettle 1500 12.5

Toaster 1200 10

Microwaveoven 1500 12.5

Coffeemaker 1200 10

Dishwasher 1200 10

Iron 1500 12.5

Portableelectricheater 1500 12.5

Windowairconditioner 1200 10

Centralvacuum 1500 12.5

Hairdryer 1800 15

Portablevacuumcleaner 1400 12

Washingmachine 500 4.2

Furnacefan 250 2

Blender 360 3

Refrigerator 700 6

Television 120 1

DVDplayer 20 0.2

Stereo 120 1

Desktopcomputerwithmonitor 180 1.5

Laptopcomputer 60 0.5

60wattincandescentlight 60 0.5

14wattcompactfluorescentlight 14 0.1

1/4horsepowermotor 700 6

1/2horsepowermotor 1000 8

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TheCommonProblemwithServiceSize

100ampservicesarecommonandtheminimumacceptableformosthomes.Howmuchelec-tricityyouneeddependsonthesizeofthehouse,andthenumberofelectricalappliances.

SERVICEToo Ahousewithanundersizedelectricalservice isnotasafetyconcern,but it isan inconve-SmALL nience.Anelectricalservicethatismarginallysizedmaysufferblowingofthemainfusesor

breaker.Thebreakerscansimplyberesetbythehomeowner,butfusesusuallyhavetobereplacedbytheutilityoranelectrician.Theentirehouse isoftenwithoutelectricitywhilewaitingforaservicecall.Thisisonereasonmoderninstallationsuseamainbreakerratherthanfuses.

Changing the service size typically means new wires from the street to the house, newconduit,anewmeterandusuallyanewservicebox.Replacingundergroundwiresismoreexpensivethanreplacingoverheadwires.

Most modern homes have acombination panel that incor-porates the service box (withthe main circuit breaker) witha panel housing the breakersthatgototheindividualcircuits.When a service in an existinghome is upgraded, a combina-tion panel is typically installed.A good installation includes apanel with room to add morecircuitsinthefuture.

2.4ServiceBox(ServiceEquipment)

dESCRIPTIon Theserviceboxincludesacircuitbreakerthatcanbeusedtoshutoffallthepowerinthehouse(newer),oraswitchwithahandlelocatedontheoutside,andtheservicefusesinside(older).Thisisyouremergencyshut-offforalltheelectricityinthehome.Theserviceboxmaystandalone,althoughinmodernhomes,acombinationpanel(servicepanel)iscommon.Thisincludesthebreakersfortheindividualbranchcircuits.


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houSEPoWER Themainswitchorbreakerisnotshutoffduringahomeinspection,sinceitwouldshutdown LEFTon theentirehouse.Thiscandisruptclocks,timersandcomputers,forexample,andcanresultin

damagetosomemotorsandcompressors.

Homeinspectorsdon’tremovethecoverforthemainbreakers inacombinationpanelforsafetyreasons.

Not all homes have a single service box. Some have a number of different points whereelectricitycanbeturnedoff.Inmanyareas,uptosixdifferentdisconnectpointsareaccept-abletoturnoffalltheelectricityinthehouse.

CommonProblemswiththeServiceBox

undERSIzEdBox Theserviceboxratingmustbeatleastaslargeastheserviceentrancewires,andthefusesorbreakersinside.Forexample,ifahousehasa150-ampservice,aboxratedforonly100ampsisnotacceptable.

undERSIzEd The fuse or breaker rating shouldmatchthewires’ current rating (ampacity) toensureanBREAkERoRFuSE adequate supply of electricity to the home and to ensure proper protection for wires. If

improperlysized,themainfusesorbreakersshouldbereplaced.

mISmATChEd Thetwomainfusesintheserviceboxshouldbethesamesizetoproperlyprotectthewires FuSESIzES andensurethesupplyofelectricitytothehomeisadequate.Iftheyarenot,anelectrician

shouldbeengagedtocorrectthesituation.

PooR Poor connections may lead to overheating and should be corrected. In some cases it is ConnECTIonS/ necessarytoreplacetheserviceboxitself. EVIdEnCEoF oVERhEATIng

dAmAgEd/ If the main switch or breaker handle is inoperative or damaged, it should be replaced. PooRLySECuREd Similarly, if the box is rusted or damaged, it should at least be checked by an electrician.

The service box should be re-secured to the wall if it is loose, to prevent poor electricalconnections.

RuST Moistureintheboxleadstorust,whichdamagestheboxandcanresultinunsafeelectricalconditions.

PooRACCESS Theserviceboxshouldbeaccessibleandinadrylocation.Theserviceboxshouldberoughly oRLoCATIon fivefeetabovethefloorandhavethreefeetclearinfrontofthebox.Serviceboxesshouldnot

belocatedinclothesclosets,bathroomsorstairwells.

nExTSTEPS Beforewemoveontotalkaboutthepanelthatbreaksthetrunkofthetreeupintobranches,let’shavealookatasafetysystemcalledgrounding.

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2.5Systemgrounding

dESCRIPTIon Thepurposeofgroundingistogiveelectricityasafeplacetogoifitgetsoutofcontrol.Whenpeopletouchliveelectricalthings,theygetanelectricalshock,andinsomecasestheydie.Groundinghelpspreventthat.

Untilroughly1960,groundingwasonlyfoundattheservicepanel.Sincethen, ithasbeenusedonallbranchcircuits,includinglightsandelectricaloutlets.Agroundwireisawirethatprovidesasafepathforstrayelectricity.

Generallyspeaking,thegroundingwiresareconnectedtometallicpartsofanelectricalsys-temthatarenotsupposedtocarryelectricity.Thesemetalcomponents(panels,switchboxes,light boxes, etc.), are close to electricity, and if something goes wrong, the metal cabinetcouldbecomelive.Apersontouchingthecabinetwouldgetashock.Connectingthegroundwiretothemetalcabinetensuresthatifsomeonetouchesthecabinet,heorshewillnotgetashock,evenifalivewireinsideistouchingthecabinet.

WhEREdoESThE The stray electricity quite literally goes to ground, where it dissipates harmlessly. In mostELECTRICITygo? houses, the electrical system is grounded to the metal water supply piping and/or one or

moreeight-footmetalrods(GroundingElectrodes)drivenintotheground.Thisallowsstrayelectricitytogetintotheground.Wheregroundingisthroughmetalsupplypiping,thegroundwire(GroundingElectrodeConductor–GEC)shouldbeconnectedtothesupplypipingnearitspointofentryintothehouse.Ifconnecteddownstreamofthewatermeterorawaterfilter,ajumperwireisprovidedacrossthemeterorfiltertomaintaintheconnectiontogroundevenifthedeviceisremoved.

oThER Othergroundingconfigurationsincludeawellcasing,alongcopperwireorbarencasedinthegRoundIng concretefooting,andametalplateorringburiedintheground.Noneoftheseisvisibleand

ELECTRodE theyarenotevaluatedduringahomeinspection. SySTEmS


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CommonProblemswithGrounding

mISSIng The system ground is missing in some cases. It may have been omitted from the originalinstallation,orremovedduringelectricalorplumbingwork;ortheoriginalgroundmayhavebeen left behind when the service panel was relocated. Adding a new ground wire is notusuallydifficultorexpensive.

WIRETyPE/ Thegroundwiremaybetoosmallfortheservicesize,thewrongmaterial,ortheremaybe SPLICES splices.Connectionsingroundwiresaregenerallydiscouragedforfearofabadconnection.

InEFFECTIVE Thesystemgroundmaybeineffective.Iftheconnectionsarepoororthewiresdamaged,the gRoundIng qualityofgroundissuspect.Ifthereisaspliceinthegroundwire,apotentiallyweakconnec-

tionexists.Groundwiresaresometimesineffectivebecausetheyaresecuredtopipesthatarenolongerinservice.Thisiscommonongalvanizedsteelplumbingpipesthatareabandoned.Iftheplumberdidnotmovethegroundwireovertothenewpiping,thegroundingsystemwillbedefeated.Bythesametoken,connectingagroundwiretoplasticsupplypipingisnoteffective,sinceplasticisnotagoodelectricalconductor.Thegroundwire(GEC)mayalsobetoosmall.

Checkingthequalityofthegroundingsystemisbeyondthescopeofahomeinspection.

LACkoF Thegroundingsystemhastobecontinuous.Thegroundwirehastobebondedtootherwires BondIng thatrelyongrounding.Thegroundwire,theservicebox,andtheneutralwireshouldbeelectri-

callybondedtogetherattheservicebox,butoftenarenot.Thissituationshouldbecorrectedpromptly.Again,thecontinuityofthesystemisnotverifiedduringahomeinspection.

BondIngAnd Thesetermsaresimilar,confusingandoftenusedinterchangeably.Strictlyspeaking,aground gRoundIng wireconnectstoground.Bondingmeansconnectingthingselectricallysotheyhavethesame

electricalpotential.Thethingsmayhaveapotentialof120volts,zerovolts,oranythingelse,aslongasbotharethesame.Theideaiswedon’twantelectricityflowingbetweenthetwo.Whenwebondsomethingtoagroundwire,everythingiseffectivelygrounded.

BondIngPIPIng Metalpipesforwaterandgascanbecomeliveelectricallyifsomethinggoeswrong.Inmany SySTEmS areas,thehotwatercoldwaterandgaspipingarebondedtogetherandconnectedtothe

systemgroundtothehousetoreducetheriskofelectricalshockfrompiping.

gRoundWIRE ConnectingthegroundwiretotheplumbingsystemdownstreamofthewatermeterisnotdoWnSTREAmoF consideredeffectivebecausestrayelectricitymaynotbeabletogetpastthemetertoground, WATERmETER especially ifthemeter isremovedforrepair!Thiscanbeeasilycorrectedbyrelocatingthe groundwireupstreamofthemeter,orprovidingajumperwirearoundthemeter.

nExTSTEPS Nowwe’lllookatthemainpanelwhereelectricitygetsdistributedthroughoutthehouse.

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3.0ServicePanel

3.1Panel(PanelboardinElectricalCodeTerms)

dESCRIPTIon Electricityiscarriedfromtheserviceboxtotheservicepanel.Modernsystemsuseacombina-tionpanelwheretheserviceboxandservicepanelareinonebox.Theblackandredwiresareeachconnectedtoaliveconnectionbar(calledabusbar–acurrent-carryingmetalbarwithseveralconnectionpoints)andthewhitewireisconnectedtotheneutralbusbar.Eachbranchcircuitisconnectedtooneofthetwobusbarsthroughafuseorcircuitbreakerthatprotectsthatcircuit.

TyPICAL The black or red branch circuit wire for an individual circuit is connected to its own smallhouSEhoLd breaker(orfuse).Thecurrentflowsthroughthebusbar,throughthebreakerorfuse,andinto

CIRCuIT theblackorredwireforthecircuit.Theelectricityflowsout,completesitscircuit,running(120-VoLT) throughwhateverfixturesorappliancesareinuseonthecircuit,andcomesbackthroughthe

white(neutral)wire.Thewhitecircuitwireisconnectedtotheneutralbar,whichisattachedtotheserviceentrancewhitewire.

Itdoesn’tmatterwhetherpoweristakenfromtheblackortheredbusbar.Theresultisthesame; a 120-volt branch circuit has been established. The typical 14-gauge copper wire isprotectedbya15-ampbreaker.

numBERoF Panels may have room for anyCIRCuITS where from four to 40 circuits.

240-volt circuits for large elec-tric appliances are establishedby combining a 120-volt blackcircuitanda120-voltredcircuit.

AuxILIARyPAnEL Whentheservicepanelisfilled,(SuBPAnEL) anauxiliarypanelcanbeadded.

Thisdoesnotbringmorepowerintothehouse;itsimplyallowsformorebranchcircuits.It’slikeadding more branches to thetreewithoutincreasingthesizeofthetrunk.


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CommonProblemswithPanels

dAmAgEd/ Wherethepanelisdamagedmechanicallyorbywater, itshouldbereplaced.Waterinthe LooSE/RuST panel causes rust and possible connection problems. Poorly secured panels should be

re-securedtothewall.

oBSoLETEPAnEL Old ceramic fuse-holders, which may or may not be in a metal cabinet, are consideredobsoleteandunsafe.Theseshouldbereplaced.Thesepanels,whichmaybefoundonwallsorceilings,haveexposedterminalconnections,anditiseasytoaccidentallytouchalivewirewhilechangingafuse.

PAnELCoVER Coversshouldbeprovidedorreplacedasneeded.Loosecoversshouldbere-securedtoreduce mISSIngoR theriskofelectricshock.Powershouldbedisconnectedpriortoremovingthecover. dAmAgEd

unPRoTECTEd Thereshouldbenoopeningsinthepanelthatallowsomeonetoreachinandtouchalive PAnELoPEnIngS electricalcomponent.Thismayoccurwherethepanelhasroomformorecircuits,orwhere

afuseblockhasnofuse.Whereverthissituationexists, theopeningshouldbecoveredorthefuseblockfittedwithafuse.Installingablownfuseonasparecircuittofillanopeningisacceptable.

Unprotected panel openings may also occur at the sides of the panel, where circuit wirestypicallyleavethepanel.Anyopeningsinthesideofthepanelshouldbeblankedoff.

undERSIzEd Wherethepanelratingissmallerthantheservicesize,thepanelmustbereplacedwitha PAnEL largerone.

PooRPAnEL Panelsarenotallowedinclothesclosets,bathroomsorstairways,forexample. LoCATIon

PooRACCESSTo Thepanelshouldbeaccessiblewiththecenterofthepanelroughlyfivefeetabovethefloor. PAnEL Thethree-footareainfrontofthepanelshouldbekeptclearforserviceaccess.

CRoWdEd Panelsshouldnotbeoverfilledwithwire.Excesswireinthepanelcanleadtopoorconnec- WIRIngInThE tionsandoverheating.Thiscanhappenifinstallersdonottrimthewiretotherightlength PAnEL insidethepanel.

dAmAgEdoR Damagedwireshouldbereplaced.Abandonedwireinthepanelmayleadtoovercrowdingor ABAndonEd confusionaboutwhatisliveandwhatisnot.Itshouldberemoved.WIREInThEPAnEL

oVERhEATEd Evidenceofoverheatingincludingdiscolorationormeltedwireinsulationshouldbeinvesti- PAnELWIRIng gatedbyanelectricianimmediately.Itmaybetheresultofalooseconnection,mechanical

damage,moistureoroverloading.

PAnELWIRIng Mostwiringleavesthepanelthroughthesideofthebox.Wiringshouldbewellsecuredwhere PooRLySECuREd itleavesthepanel.Acableconnectorisusedtomakesurethewireisnotexposedtothesharp

edgesoftheholeinthebox,andtosecurethewiresothatifsomeonepullsonthewire,itwillnotloosentheconnectionsinsidethepanel.Wheretheseconnectorsaremissing,theyshouldbeprovided.

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douBLEd-uP Peopleoftenaddcircuitsasahouseexpandsoraselectricalneedsgrow.Insomecases,circuits CIRCuITS inthepanelaredoubledbyaddingasecondwiretotheterminalscrewforonebreakerorfuse. douBLE-TAPS, Thisdouble-tappingordouble-luggingisnotpermittedandshouldbecorrected.Themost douBLE-LugS commonsolutionisaddinganauxiliarypanel.Replacingtheexistingpanelwithalargeroneis

acceptablebutmoreexpensive.Thismakessenseiftheexistingpanelisdamagedorveryold.

Somemanufacturershaveaspecialcircuitbreakerdesignedtoholdtwowires.Someauthori-tiesdonotacceptthesetypesofbreakers.Securingthreewiresunderoneterminalscrewisneveracceptable.

undERSIzEd Whereanauxiliarypanelisused,thewirefromtheservicepaneltotheauxiliaryshouldbe WIREFEEdIng protectedbybreakersorfusesinthemainpanel.Thewiresizeshouldbelargeenoughtocarry AuxILIARyPAnEL theloadfromtheauxiliarypanel.Iftheauxiliarypanelisratedat60amps,thewirefeedingit

shouldalsoberatedat60amps.Thiswouldbea6-gaugecopperwire.

InAPPRoPRIATE Thegroundwireandneutralwireshouldnotbebondedtogetherinanauxiliarypanel.This BondIngATThE mayturnthegroundingwireintoacurrent-carryingwireinadvertently,creatingadangerous AuxILIARyPAnEL situation.

SuSPECTPAnEL Someelectricalpanelshavebeenthesubjectofsomecontroversyandtherehavebeenrecalls.

3.2FusesandBreakers

dESCRIPTIon Fusesandbreakersperformthesamefunction.Theyarethebrainsoftheelectricalsystemandshutoffthecircuitwhentoomuchcurrentisflowing.Acircuitbreakercanbeturnedbackonaftertheoverloadsituationiscorrected.Afusehastobereplaced.

dAngERouS People sometimes get frustrated with fuses blowing. They do not understand that this is PRACTICES signalingaseriousproblem.Bypassingafuseisaverydangerouspractice.Itisfoolishtowrap

ablownfusewithfoilorputapennyinafuseblock.Thismaycauseafire.

oVER-FuSIng Onedisadvantageoffusesisthatitiseasytousethewrongsizefuse.Itisunfortunatethat15,20,25and30-ampfusesallfitintothesamefuseblock.Anoversizedfuseorbreakerwillnotshutoffthecircuitintimetopreventoverheating.Circuitbreakersaretypicallynotchangedbythehomeowner,andarelesslikelytobeincorrectlysized.

FuSEREjECToRS Fuserejectorwashersaresmallplasticringsthatareinsertedintothefuseblock.Therearedifferentrejectorsfor15,20,25and30ampfuses.Fuserejectorspreventthewrongfusefrombeingscrewedintothefuseblock.

TyPECFuSES Here’s another way to prevent over-fusing: Type C screw-in (plug) fuses are non-interchangeable.Thismeansthatthewrongsizefusewillnotfitintothefuseholder.

oThERTyPES Fusesratedat15,20,25and30ampsareglassscrew-intypefuses.Largerfusesarealways oFFuSES cartridgetypewithametalcollarateachend.Cartridgefusesarealsoavailableinsmaller

sizes.

TImEdELAy Whenelectricmotorsstartup,theydrawalotofelectriccurrentforaveryshorttime.Insome (TyPEd)FuSES casesthiscanleadtonuisancefuseblowing.Specialtimedelay(TypeD)fusesallowthisextra

electricityforaveryshorttime.Thisisokay,becausethingswillnotoverheatinasecondortwo.Circuitbreakershavethistimedelayfeaturebuiltin.


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TyPEPFuSES TypePfuseshaveanaddedsafetyfeature.Thelowmeltingtemperatureofthisfusesensesheatbuild-uparoundthefuse,whichmaybecausedbyapoorconnectionbetweenthefuseitselfandthefuseholder.Poorconnectionscanoverheatandcausefireswithcurrentflowsthataretoosmalltoblowafuse.

WhIChCIRCuIT Mostcircuitbreakerstripbymovingtheswitchtothemiddleposition,otherssimplyswitchtoISoFF? theoffposition.Itisusuallyveryeasytoseewhichcircuitbreakerhastripped.Thecircuitis

re-activatedbysimply‘switching’thebreakeroffandonagain.Withfuses,itisnotalwayseasytoseewhichonehasblown.Onglassfuses,youcanusuallyseeifyoulookcloselythroughtheglass,butonacartridgetypefuseitisoftendifficulttoknow.

CommonProblemswithFusesandBreakers

oVER-FuSIng The most common flaw withfusepanelsisfusesthatarethewrong size for the wire. Thisunsafe condition should becorrected promptly to preventoverheating of the wire. Theillustrationbelowshowstheap-propriate size of fuse for givenwiresizes.

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dAmAgEdoR Abrokenordamagedfuseholderorcircuitbreakermaynotoperateproperlyandshouldbe LooSE replaced.Poorlysecuredfuseholdersorcircuitbreakersmayresultinpoorconnectionsand

shouldbere-securedorreplaced.

douBLEd-uP Peopleoftenaddcircuitsasahouseexpandsoraselectricalneedsgrow.Insomecases,circuits CIRCuITS inthepanelaredoubledbyaddingasecondwiretotheterminalscrewforonebreakerorfuse. (douBLE-TAPS, Thisdouble-tappingordouble-luggingisnotpermittedandshouldbecorrected.Themost douBLE-LugS) commonsolutionisaddinganauxiliarypanel.Replacingtheexistingpanelwithalargerone (TExTREPEATEd is acceptable but more expensive. This makes sense if the existing panel is damaged or FoRCLARITy) veryold.

Somemanufacturershaveaspecialcircuitbreakerdesignedtoholdtwowires.Someauthori-tiesdonotacceptthesetypesofbreakers.Securingthreewiresunderoneterminalscrewisneveracceptable.

3.3240-VoltCircuitsandmulti-wire120-VoltCircuits

dESCRIPTIon Heavy duty appliances use 240-volts. These include electric ranges, ovens and cook tops,clothesdryers,electric furnacesandheaters,airconditionersandwaterheaters.Here, theblackwireandredwirearebothusedinthecircuit.Formostoftheseappliances,awhiteneutralwireisalsoused.

Multi-wire120-voltcircuitsusecableswiththeblack,redandwhiteconductor.Atsomepointinthecircuit,thesesplitintotwo120-voltcircuits.Thesecircuitscanbeusedtoreducetheamountofwirethathastoberunthroughoutthehouse.Thesearecommonfordishwashersandgarbagedisposals,forexample.Theymayalsobeusedatkitchenreceptacles.Thetophalfofthereceptaclecanbeononecircuitandthebottomhalfcanbeonanother.Thisallowsthetwo appliances to be plugged in to the same outlet without blowing a fuse or trippingthebreaker.Thesecircuitshavetwofusesorbreakers,justlike240-voltcircuits.

Twobreakers(orfuses)areneeded;onefortheblackwire,andonefortheredwire.Thesetwobreakers(orfuses)shouldbelinkedsothatifoneisswitchedoff(breaker)orpulledout(fuse),theothermustbeswitchedofforpulledoutwithit.Thisisasafetyfeaturetopreventelectricshocks.Ifonlyonepartofthecircuitwasturnedoff,therewouldstillbepowertotheotherpart.Itwouldnotbesafetoworkonthesystem.


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Circuitbreakersshouldhavemechanicaltiesorlinkstomakesurebothareturnedoff.Therearealsospecialdoublecircuitbreakerswithasinglehandle.Withfuses,doublefuseholdersareusedthatmustbepulledouttogethertodisconnectthecircuit.

TheCommonProblemwithMulti-wireCircuits

mISSIngLInkS Themostcommonissuewith240-voltcircuitsandmulti-wire120-voltcircuitsistheabsenceFoRBREAkERSoR ofthedevicetomakesurebothcircuitsareturnedoff.Inmostcases,thisimportantsafety

mISSIng improvementisinexpensive. PuLLouTSFoR FuSES

nExTSTEPS Beforewemoveonand lookatthewiringthroughoutthehouse,wearegoingto lookatacoupleofotherdevicesthathelpcircuitbreakersandfusesmakehousessafer–groundfaultcircuitinterruptersandarcfaultcircuitinterrupters.Thenamesareconfusingbuttheconceptsaresimple.

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3.4groundFaultCircuitInterrupters

dESCRIPTIon These safety devices have been around since about 1970. They improve the safety ofregularcircuitbreakersandfusesbyreducingelectricshockhazards.Insteadoflookingfortoomuchcurrentflowing,theylookforcurrentgoingwhereit’snotsupposedtogo.Theyshut the power off when aslittle as .005 amps are leaking.Under normal circumstances,the same amount of currentis flowing at any point in thecircuit. If there are five ampsflowing out through the blackwire,thereshouldbefiveampscomingbackthroughthewhitewire. If there is a difference,currentisescapingsomewhere,andthisisdangerous.TheGFCIshuts down the circuit when itmeasures different currents intheblackandwhitewires.

Modern electrical codes require ground fault protection where there is the potential forwatertocomeintocontactwithelectricity.Thisincludesreceptaclesforbathrooms,kitchencountertops, wet bars, laundry tubs, spas and hot tubs, whirlpool baths, swimming pools,unfinishedbasementsandoutdoorreceptacles.

ProtectionmaybeprovidedbyGFCIcircuitbreakersorreceptacles.GFCIcircuitbreakersatthepanelprotecttheentirecircuit.GFCIreceptaclesprotectonlythatoutlet,andthedownstreamoutletsonthatcircuit.Note:weusethetermsreceptacleandoutletinterchangeably,asmosthomeownersdo.

Whileelectricalcodesrequirethesedevicesinnewwork,theydonotrequirethemonexist-inginstallations,althoughtheextraprotectionaffordedbythesedevicesisdesirable.CoderequirementsforGFCIshavechangedseveraltimessincetheywereintroducedin1970.

IdEnTIFICATIon Ground fault circuit interrupter breakers at the panel can be identified by the Test andReset buttons. Ground fault interrupter receptacles can also be identified by the TestandResetbuttons.


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CommonProblemswithGroundFaultCircuitInterrupters

mIS-WIREd Inadditiontothenormalproblemsthatmaybetheresultofmis-wiredelectricalreceptacles,amis-wiredGFCIreceptaclemaynotshutoffthecircuitasexpected.Acommonproblemisthereversalofthe“line”and“load”connectionsonthebackorsidesoftheoutlet.NewerGFCIreceptacleswillnotresetifthewiringisdoneimproperly.Correctingthisproblemisquickandinexpensive.

mISSIng GFCIsmaynotbeprovidedinnewworkasrequiredbylocal jurisdictions.Replacingcon-ventional breakers with GFCI breakers is not difficult, although GFCI breakers are moreexpensive.

TESTFAuLTy/ GFCIshavea testbuttonthatsimulatesagroundfaultsituation.PressingthisbuttonwillInoPERATIVE causethebreakertotripifitisworkingproperly.Ifthetestbuttondoesnottripthebreaker,

the device may have to be replaced. Since this test turns off the power to everythingconnectedtothecircuit,manyhomeinspectorsdonotperformthistest.

TheremaybenopowertotheGFCI.Aspecialistshouldbeengagedtoinvestigate.

3.5ArcFaultCircuitInterrupters

dESCRIPTIon ArcFaultCircuitInterrupters(AFCIs)helpprotectagainstfiresbydetectingarcing.Arcingisanelectricalproblemthatoccurswhenelectricityjumpsfromoneconductoracrossaninsulatortoanotherconductor.Lightandheataregeneratedasthecurrentpassesthroughtheinsula-tor,whichmaybeairorasolidinsulatingmaterial.Arcfaultsarecommonwhereelectricalcordsaredamaged,orwhereoutletsarenotproperlyinstalled.

GFCIsaredesignedtopreventelectricalshock.AFCIsaredesignedtopreventfires.GFCIslookforelectricitythat isnotwhere it’ssupposedtobebymeasuringcurrentrunningthroughwires.AFCIslookforoverheatingbymonitoringthewaveformofthecircuitvoltage.

Arcfaultsaredangerousbecausethe heat generated may ignitenearby combustible material,startingafire.Arcfaultcurrentsare often too small to trip abreaker or blow a fuse. A GFCIwill not detect arc faults. AnAFCIbreakerprotectstheentirecircuit.

WhEREnEEdEd In houses built since roughly2001,AFCIshavebeenrequiredon circuits serving bedrooms.In some areas, codes have ex-tended this requirement tootherareasinthehouse,suchaslivingrooms,diningroomsandhallways.Theydonothavetobeaddedtoexistinginstallations.

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CommonProblemswithArcFaultCircuitInterrupters

mISSIng AFCIsmaynotbeprovidedinnewhomesasrequiredbylocaljurisdictions.Replacingconven-tionalbreakerswithAFCIbreakersisnotdifficult,althoughAFCIbreakersaremoreexpensivethanconventionalbreakers.

FAuLTy AFCIshaveatestbuttontosimulateanarcingsituation.Pressingthisbuttonwillcausethebreakertotripifitisworkingproperly.Sincethisturnsoffthepowertoeverythingconnectedtothecircuit,manyhomeinspectorsdonotperformthistest.

4.0BranchCircuitWiring

4.1BranchCircuitWire:(distributionWiring)

dESCRIPTIon Thewirecarryingelectricityfromthepaneltothefixturesandappliancesistypicallycopper,althoughaluminumwascommonlyusedfromthemid-1960stothe late1970s.Eachpost-1960cableismadeupoftwoconductorsandonegroundwire.Pre-1960installationsdidnotincludeagroundwireineachbranchcircuit.(Notes:Datesareapproximate.Weusethetermswireandconductorinterchangeably.)

Theconductorsarewrappedwithcolor-codedplasticinsulation.Onolderwiring,theinsula-tionwasrubber.Thegroundwireisnotinsulated.Thisgroupofthreewiresistypicallywrappedinaplasticornylonsheathing.Oldersheathingswerepaper,clothandrubber.Flexiblemetalcableandrigidmetalconduitarealsousedassheathing.

BLACkAnd Oneconductorhasblackinsulationandistheliveorhotwire.Theotherconductorhaswhite WhITEWIRE insulation and is referred to as the neutral. Neither wire should be touched when there

ispowertothecircuit.Theblackandwhitewirescarrythecurrent.Thevoltageavailableis120volts,andthecurrentflowislessthan15amps.

gRoundWIRE Thegroundwireisnormallyidle.Ifthereisaproblem,thegroundactsasanescaperoutefor (EquIPmEnT theelectricity,inducingthecurrenttoflowthroughthiswiretotheground,ratherthaninto gRoundIng aperson,causinganelectricalshock.GroundeddistributionwiringwasintroducedtoresidentialConduCToR–ECg) electricsystemsinthelate1950s.

ThREE 240-voltcircuitsandmulti-wire120-voltcircuitshaveanadditionalliveorhotwire,aswehave ConduCToR discussed.Thiscablecontainsablack,red,andwhiteinsulatedwireaswellasanuninsulated CABLE groundwire.

WIREgAugE Thenormalwiresizeis14-gauge.Thisiscapableofcarrying15ampssafely.Afuseorcircuitbreakerratedat 15ampsshouldalwaysbeprovidedona 14-gaugecoppercircuit. Insomecases,20-ampcircuitsservekitchenorotheroutlets.Thecopperwiresizeforthesecircuitsshouldbe12-gauge.


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dEdICATEd All240-voltappliancesgetdedicatedcircuits.Thisincludesthingslikestoves,waterheaters, CIRCuITS air conditioners, clothes dryers, hot tubs and saunas. Some 120-volt appliances also get a (IndIVIduAL dedicatedcircuit.Thisincludessuchthingsasthefurnaceorboiler,dishwasher,foodwasteBRAnChCIRCuITS) disposal,compactor,centralvacuumsystem,microwaveoven,refrigerator,freezer,washing

machine,whirlpoolbathtub,andelectricheaters.Splitreceptacles(outletswherethetopandbottomhalvesareonseparatecircuits)arealsousuallyondedicatedcircuits.Exteriorout-letsareoftenononededicatedcircuit.Ahomeinspectionwillnotidentifywhichcircuitsarededicated.Thesearedeterminedwhentheelectricalcircuitsarelabeled.

noTASAFETy Dedicated circuits are rare in older houses and it is very difficult to verify during a visual ConCERn inspection.Itisnotamajorexpensetorearrangethis,andtheissueisnotoneoflifesafety,

simplyamatterofconvenience.Withoutdedicatedcircuitsforeachoftheseappliances,thereisthepossibilityofnuisancefuseblowingorcircuitbreakertrippingwithseveralappliancesinusesimultaneously.

REFRIgERAToR Thereasonarefrigeratororfreezergetsadedicatedcircuitistopreventfoodspoilage.Ifitis AndFREEzER onacircuitwithotherappliances,thefuseorbreakermaybeblownasaresultofaprob-

lem with another appliance. The fuse or breaker may not be replaced immediately if thehomeownerdoesn’tknowthattherefrigeratororfreezerisalsoonthiscircuit.Asaresult,foodmaybespoiled.Again,homeinspectorswillnotpickthisup.

FuRnACEoR Theheatingsystemshouldbeonadedicatedcircuit.Iftheheatingsystemwastoshutdown BoILER duetoanoverloadfromanotherappliance,thehousewouldbewithoutheat.Thiscanresult

infreezingifthehomeisunoccupiedforsometime.

hEAVyCuRREnT Some appliances need dedicated circuits because of their heavy electrical draw. Putting dRAW additionaloutletsandlightsonthecircuitmayleadtoregularshut-downs.

CommonProblemswithBranchCircuitWiring

dAmAgEd Wirethatisdamagedorhasbeenoverheatedshouldbereplaced.Wirethatisnickedissmallerindiameteratthatspot.Thesmallerthewire,themoredifficultitisforelectricitytomovethrough. (The resistance is higher.) This can lead to localized overheating, and eventuallyafire.

oPEnSPLICES Connectionsshouldbemadeinsidepanelsorjunctionboxes.Exposedconnectionsarenotsafeandshouldbecorrected.

CABLE Wireshouldbeprotectedfromthemetaledgesofpanelsandboxeswithappropriatecable ConnECToRS connectors.Thisisusuallydonewithbushings,grommetsorcableclamps.Thesedevicesnot mISSIngoR onlyprotectthewirefromthesharpedges,buttheysecurethewire,sosomethingpullingon InEFFECTIVE the wire will not cause a loose connection. Missing or ineffective connectors should be

replaced.

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LooSEoR Wiring which is poorly secured should be re-secured as necessary to protect it fromdAmAgEd mechanicaldamageandreducetheriskofelectricshock.Thewireshouldbesecuredwhereit

entersapanel,junctionboxorfixture.Thewireshouldbesecuredwithin12inchesofthebox,andeveryfourandahalffeettofivefeetthereafter.

If cable staples are used, onlyonewireshouldbesecuredun-der each staple. Staples shouldbe the appropriate size for thewire.Inappropriatestaplingcandamagethecable,riskingover-heatingorelectricshock.

ExPoSEdTo Wires should not be exposeddAmAgE to mechanical damage. Wires

shouldbe runthrough joists inunfinished basements, ratherthan on the underside, wheretheyaremorelikelytobedam-aged. Wires should be set wellback from any nailing surfacein stud walls, to avoid a nailbeingdrivenintothewires.Alternatively,steelplatesshouldbeusedtoprotectthewiresfromnailsorscrews.

Wireshouldnotberunalonginteriorsurfacesofwalls,floorsorceilingsinfinishedareas.

ExPoSEdInATTIC Ideally,thejoistsshouldbedrilledandthecablesshouldberunthroughthem.Althoughverycommon,itisconsideredpoorpracticetosecurethecabletothetopofthejoists.

don’TWALk Walking through an insulated attic where you can’t see what you are stepping on is veryThRough dangerousbecausewiringisoftenrunalongthetopoftheatticforjoistsortrusses.That’s

InSuLATEdATTICS whyhomeinspectorsdon’tdoit,andyoushouldn’teither.

dAmAgEd The wiring may be damaged by rodents. Mice and squirrels in the attic, for example, canInSuLATIon damagewiringinsulationandcreateafirehazard.This isoftendifficulttodetectwithout

pullingbacktheinsulation.Wherepestsareknowntohavebeeninahome,anelectricianshouldinspectthewiring.

unPRoTECTEd Wherewiringisrunonthesurfaceofwalls,baseboardsorotherinteriorfinishes,itshouldbeSuRFACEWIRIng protectedfrommechanicaldamagewitharigidcovering.


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TooCLoSETo Wiringshouldbekeptat leastone inchawayfromheatingductsandhotwaterpipingtoduCTSAndPIPIng avoidoverheatingthewire.Insulationcanbeusedtoseparatethesematerials.

undERSIzEdWIRE Wirethatistoosmallfortheapplianceitserves,orfortherestofthecircuitwiring,shouldbereplacedtoreducetheriskofoverheating.

ExTEnSIon Extension cords should not be used as permanent wiring, and should never be stapled to CoRdSuSEdAS walls,floorsortrim.Cordsshouldnotrunundercarpetsorgothroughdoorwaysorwindows. PERmAnEnT Thesepracticesarefirehazards. WIRIng

ABAndonEd Wiresthatarenotinuseshouldberemovedorthewireendsshouldbeterminatedinjunction WIRIng boxestopreventconfusionandelectricalshocks.

ImPRoPER Exteriorwiringshouldbesuitableforoutdooruse.TherearedifferenttypesofexteriorwireExTERIoRWIRIng forabovegradeandbelowgrounduse.Exteriorwiringshouldbeprotectedfrommechanical

damageandspecialexteriorjunctionboxesarerequired.

Smaller electrical wires (14-gauge, 12-gauge and 10-gauge) are made up of a single solidconductor.Largerwires(8-gaugeandlarger)aremadeupofanumberofstrandsofsmallerconductors.Thesestrandedwiresaremuchstrongerintensionthansolidconductors.Solidconductors(10-gaugeandsmaller)cannotberunasoverheadunsupportedwiringbecausethemetalmayfatigue.Solidconductoroverheadwiringshouldbereplaced.

oVERLoAdEd Whileitisdifficulttotellfromavisualinspection,thenumberoflightsandoutlets(receptacles) CIRCuITS onanygivenbranchcircuitshouldbesuchthatthecircuitwillnotdrawmorethanthecircuit

rating(typically15amps)undernormalcircumstances.Atamaximum,12lightsand/oroutletsshouldbeconnectedtoeachcircuit.Thepracticallimitation,however,isifoneoftheoutletsisusedforahairdryer,whichmaydrawcloseto15amps,itiswisetoconnectthecircuitonlytootheroutletswhichwillbeusedforvery low-drawingappliancessuchasclocks,radios,televisions,computersor lights.Mostcircuitsserveacombinationofelectricalreceptaclesandlights.

TERmInoLogy Electricity is confusing, there’s no getting around it. Here’s an example of what electrical douBLE-TALk puristscallthings:Blackandredwiresareliveandarecalled‘ungrounded’conductors.White

wires are neutral and are called ‘grounded’ conductors. Ground wires are the emergencysystemandarecalled‘grounding’conductors.That’sjustcruel.

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4.2knob-and-TubeWiring

dESCRIPTIon Knob-and-tubewiringwasusedinhomesuntilapproximately1950.Whiledifferentthanthewiringthatisusednow,itisnotnecessarilyinferior.Thiswiregetsitsnamefromtheceramicknobsthatsecureitandtheceramictubesthatprotectthewireasitpassesthroughwood-framingmemberssuchasfloorjoists.

SEPARATEBLACk The black and white wires inAndWhITE knob-and-tube systems are

run separately, in two distinctcables. In modern cables, theblack wire, white wire andground wire are all wrappedup in a single cable. It was feltoriginally,thathavingtheblackwire and white wire separatewassafer,sincetherewasverylittle chance of the black andwhite wires ever touching, cre-atingashortcircuit.Thishasnotprovedtobeabigproblemwithmoderncables.

nojunCTIon Anotherdifferencebetweenknob-and-tubewiringandmoderncableisthatwithknob-and-BoxES tubewiring,electricaljunctionboxeswerenotusedtoconnectwires.Inmodernconstruc-

tion,wiresmustbeconnectedinsideaclosedbox.Knob-and-tubeconnectionsweremadebytwistingthewiringtogether,solderingthewires,andwrappingtheconnectioninrubber,theninelectricaltape.Whilenolongeracommonpractice,ifproperlydoneandnotdisturbed,theseconnectionswillserveindefinitely.

nogRoundWIRE Another difference between knob-and-tube wiring and modern cable is the absence of agroundwire.Asmentionedearlier,knob-and-tubewiringwasusedupuntil1950.Fromthe1950s to roughly 1960, two-conductor cable was popular, although no ground wire wasincluded.Sinceroughly1960,groundwireshavebeenincorporatedintothetwo-conductorcable,andelectricalreceptaclesincludedathirdslot(forthegroundingpin)thereafter.

WIREInSuLATIon Anotherdistinctionbetweenknob-and-tubewiringandsomemoderncablesisintheinsula-tion.Theknob-and-tubewiringusedrubberinsulationandclothsheathingaroundthewiring.Inmoderncables,eachwirehasplasticinsulationtypically,andtheentirecableiswrappedwithanotherlayerofplastic.Overtheyears,thesesheathingmaterialshaveincludedcloth,paper,rubber,metalandplastic.

BRITTLE Breakdownoftheinsulationonknob-and-tubewiringisoftenthereasonitisreplaced.ThisisInSuLATIon frequentlytheresultofoverheatingormechanicalabuse.

REPLACEmEnT Whileknob-and-tubewiringmustberecognizedasold,itisnotnecessarytoreplaceitasamatterofcourse.Itshouldbeinspectedandevaluatedonanindividualbasis.


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CommonProblemswithKnob-and-TubeWiring

PooR Problemswithknob-and-tubewirealmostalwaysresultfromamateurishconnectionsmadeConnECTIonS after original installation. Since original connections were made without junction boxes,

manyhomeownersfelttheytoocouldmakeconnectionstoknob-and-tubewiringwithoutjunctionboxes.Thisisanunsafepractice,particularlysincethechanceofmakingaspliceasgoodastheoriginalconnectionisveryremote. Inanycase,thisviolatesmodernelectricalrules.

dAmAgE Since knob-and-tube wiring isinvariably old, it has been sub-ject to more home handymen,more mechanical abuse (suchas items stored on top of thewire in the basement or attic),and is more likely to have suf-fered wear and tear. Pinchedwiringanddamaged insulationisaproblem,particularlyinun-finished basements, where thewiringisexposed.

BRITTLE Another problem is brittleknob-and-tube wire insulation,whichmayoccurifthewirehasoverheatedinthepastasaresultofover-fusing,apoorconnectionordamagedcable.Oftenthewirebecomesbrittleinhighheatareas,suchaspanelsandjunctionboxes.Inexposedareas,whereinspectioniseasy,thereisusuallygoodaircirculationandlittleheatbuild-up.Thewiresareleastlikelytobebrittleintheseareas.

Brittlewireinsulationmaybeaproblemwherethewireisburiedinatticinsulation.Thisiscommoninatticswhereinsulationhasbeenupgraded.

CIRCuITS Since older electrical systems had few circuits by today’s standards, the chances of eachExTEndEd knob-and-tubecircuithavingbeenextendedovertheyearsareverygood.Whilethisisnot

necessarilyaproblem,theadditional loadsandthepossibilitiesofpoorconnectionsmakean argument for replacing older knob-and-tube wiring. This is often cost-effective duringremodeling.

TWoFuSE Inallmodernsystems,thereisonlyonecircuitbreakerorfuseatthebeginningofeachcircuit.CIRCuITS(FuSEd Thereisaverygoodreasonforthis.Whenwewanttoworkonacircuit,wehavetoturnit

nEuTRALS) off.Usingthefuseorcircuitbreakerisacommonwaytodothat.Ifthefuseorbreakerisattheendofthecircuit,turningitoffwillleavetheentirecircuitliveuntilwegettothebreaker.Thatmakesitverydangeroustoworkonthesystem.

Anotherproblemspecifictoknob-and-tubewiringisthepresenceoftwofusesonasinglecircuit.Boththeblackandwhitewireshavefusesonsomeveryoldpanels.Thismeansthereisafuseatthebeginningandattheendofthecircuit.Ifthefuseontheneutralwireblows,

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thefixturesandappliancesonthiscircuitwillnotwork.Itisnotsafe,however,toworkonthecircuit!Powerisstillavailablethroughthecircuit,rightuptotheblownfuse.Apersoncouldgetashockinthiscase.Bytheway,onefuseoneachcircuitisperfectlyadequate.

Wecanreplacetheseoldpanelstosolvetheproblem,withouthavingtoreplacetheknob-and-tubewiringthroughoutthehouse.

InSuRAnCE Somecompanieswillonlyprovideinsuranceafteraninspectionandapprovaloftheknob-and- dIFFICuLTIES tubewiringbythelocalauthorities.Manycompanieswillnotofferinsuranceatallonhouses

withknob-and-tubewiring.

REPLACEWhEn Itismuchlessexpensivetoreplacewiringinahomewhenremodelingahome.Walls,ceilings REmodELIng andfloorsareopenedupandaccessible.Manyhomeswithknob-and-tubewiringhavethe

wiringreplacedasindividualroomsareremodeled.It’sverycommontofindpre-1950shomeswithacombinationofknob-and-tubeandmodernwiring.

4.3AluminumWire

dESCRIPTIon Aluminumwiringwascommonlyusedfromthemid-1960suntilabout1978.Itwasintroducedbecauseitwaslessexpensivethancopper.Itwasrecognizedfromthestartthataluminumwiring is not quite as good a conductor of electricity as is copper. As a result, 12-gaugealuminumwasusedinplaceof14-gaugecopperfora15amphouseholdcircuit.Otherwiresizeswerealsosuitablyincreased.Thiswasfine.

ThERmAL Someotherpropertiesofaluminum,however,werenotrecognizedanddidcauseproblems. ExPAnSIon Firstly, aluminum has a higher co-efficient of thermal expansion than copper. This means

thatwhenthewireheatsup(asallwiredoeswhenelectricityflows)thealuminumtendstoexpandmorethancopper.Thisleadstothewiretryingtomoveoutfromundertheterminalscrewsatconnections.Thisphenomenoniscalled“creep”andcanleadtopoorconnectionsandsubsequentoverheating.

SoFT Secondly,aluminumissofterthancopper,andelectriciansusedtoworkingwithcopperwouldoftennickaluminumwiringinadvertently.Nickingthewire,ofcourse,reducesitsdiameter,anditsabilitytocarryelectricity.Localizedhotspotscandevelopwherethewirehasbeennicked.Further,ifthewireisbentafterithasbeennicked,itwilloftenbreak.

InSuLATIng Lastly,theoxideofaluminumthatformsonthewireisaverypoorelectricalconductor.All oxIdE metalsrustoroxidize.Thegreenishcopperoxidethatformsoncopperwiringisnoproblem

becauseitisagoodelectricalconductor.Theoxidethatformsonaluminumcanleadtohigherresistanceandhighertemperatures.

Cu-AL&Co/ALR Asaresultofthesedifficulties,specialcomponents,designatedCU-ALorAL-CU,wereintro-duced.Thesecomponentscanbeusedwitheithercopperoraluminumwiring.Theseincludedwireconnectors(wirenuts),electricalreceptacles,circuitbreakers,stoveblocks,etc.Inmostcases, these improvements were satisfactory. However, electrical receptacles and lightswitchescontinued to be a problem.The subsequently designed receptacles andswitchesweredesignatedCO/ALR.ThisdesignationmeansCopper/AluminumRevised.


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Onealternativetousingspecialcomponents is to join the alu-minumwirestoshort“pig-tails”ofcopperwire justbeforetheyconnect to outlets, distributionpanelterminals,andsoon.Theconnectionbetweenthealumi-num and copper wire is madewith a connector known to beappropriate. There are connec-tors specifically approved forthispurpose.

SPECIALSySTEmS Thereweresomespecialsystemsdevelopedtoconnectcopperandaluminumwire.Manyarenolongeravailableandinstallationsaretypicallyevaluatedindividuallybyanelectrician.

ACCEPTABLE Aslongasproperconnectorsareused,andtheconnectionsaremadewithoutdamagingthewire,aluminumwiringisconsideredsafe.Itispermittedforusebyelectricalcodes,althoughit isnotcommonlyused inhomesdueto theadversepublicity it receivedduring itsearlyproblemyears.Itisstillusedcommonlybyutilitiesinstreetwiringandforserviceentrancecables.Insomeareas,aluminumisstillcommonlyusedfor240voltapplianceslikerangesandairconditioners.

CommonProblemswithAluminumWiring

PAnEL/BREAkERS/ Wherespecialdevicesorconnectorshavenotbeenprovidedforaluminum,theyshouldbeRECEPTACLES/ added.Itisoftendifficulttoknowwhetherthesmalltwist-onconnectorsareappropriate.

ConnECToRS– Thesafestthing is toreplacethemwiththoseknowntobeappropriate.Forexample, thenoTPRoPERLy smalltwist-onconnectorsaresosmallthattheyarenotmarkedCU-AL.Theyarenowcolor-

RATEd coded,butonolderones it isdifficulttoknowwhetherornottheyareappropriate.Sincetheyonlycostafewcentseach,itmakessensetoreplacethemwiththoseknowntobethecorrect type. Some experts do not consider twist-on connectors to be appropriate for usewithaluminumwire.

InSPECTIonBy Theexaminationofeveryelectricalconnectioninthehomeisnotpartofahomeinspection.SPECIALIST Theprovisionofspecialaluminumcompatibleconnectorsisnotanexpensiveundertaking.

RECommEndEd Werecommendthatthespecialistcheckallthedevicesinthehomeofaluminumwiringandmakeimprovementsasneeded.

oVERhEATIng Aluminum wires that show evidence of overheating should be further investigated by aspecialist.Theremayormaynotbeasignificantproblem.

AnTI-oxIdAnT Connectionsonlargegaugealuminumwiresaretypicallycoatedwithaspecialgreasetopre-mISSIng ventcorrosion.Wherethisismissing,aluminumoxidemaybuildupandthewiresmayoverheat.

nExTSTEPS We’vetalkedabouteverythingrightuptoandincludinghowwegetelectricitythroughthehouse.Nowwe’llhavealookattheendpointswhereitgetsused.

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5.0outlets,Lights,SwitchesAndjunctionBoxes

5.1outlets(Receptacles)

dESCRIPTIon Electricaloutletsareusedtopluginportablelights,appliances,heaters,etc.Mostoutletsareduplex,meaningthatwecanplugintwoappliances.Theyareusuallylocatedinwalls,butcanalsobeinstalledinceilingsandfloorsinspecialcases.Anadequatenumberofconvenientreceptacles is a distinct advantage for today’s lifestyles. Situations that require extensioncordsareinherentlydangerous.

ThERuLESkEEP Therulesaroundelectricaloutletschangeregularly.Mostexistinghouseswillnotcomply ChAngIng with the most current code requirements. While improvements are possible, this is not

consideredadefect.

PoLARIzEd Until 1960mostreceptacleswereungrounded.Theyhadonlytwoslots inthem,onecon-nectedtoablackwireandoneconnectedtoawhite.Outletstypicallyhavethetwoslotsindifferentsizes,(polarizedreceptacles)sothatapolarizedappliancecouldonlybeinstalledintheproperorientation.Thesmallerslotisdesignedfortheblackwire(hotorlivewire)andthelargerslotisconnectedtothewhite(neutralwire).

LIghTSoCkET Polarityisimportantonsomeappliances.Insomecases,polarityisimportantforsafety.In PoLARITy othersitisimportantforproperoperationoftheappliance.

Alampisagoodexampleofanappliancethathasapolarizedplugforsafetyreasons.Therearetwoelectricalcomponentsofthelightsocketthatmaybeliveelectrically.Thethreadedcollararoundthesocketisonehalfoftheconnection,andthebrassbuttonatthebottomofthesocketistheotherconnection.Apersonismuchmorelikelytotouchthethreadedcollarthatcomesuptothetopofthesocketwhenreplacingalightbulb,soitissafertomakethatthewhite(neutral)connection.Theblack(live)connectionatthebottomofthesocketislesslikelytobetouched.

Somehomeentertainmentsystemsrequirepolarizedconnectionstooperateproperly.

BLACkToBRASS Manymodernoutletshaveabrasscoloredscrewononesidetowhichthelive(usuallyblack)wireisconnected.Thewhite(neutral)wireisconnectedtothesilvercoloredscrewontheopposite side, and the ground wire is connected to the ground screw (usually green) neartheendoftheoutlet.


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PuSh-In, Somemodernoutletsdonothavescrewsonthesidestoholdwiresinplace,buthaveholesin BAyonEToR theback, intowhichthewiresarefitted.Thesearecalledbayonet,daggerorpush-intype dAggER connectors,becauseofthewaythewireisinserted.Theseoutletswereparticularlytrouble-

somewhenusedwithaluminumwire.

TAmPER Tamper-resistantreceptaclesaredesignedtopreventchildrenfrominsertingthingslikepaper RESISTAnT clipsorkeysintothereceptacle.Aninternalmechanismwillblocksuchattemptsunlessboth

prongsofaplugareinsertedintotheoutletatthesametime.

gRoundEd The grounding of electrical outlets, which became popular after 1960, affords additional ouTLETS protection.Thegroundwireisathirdwirethatnormallyconductsnoelectricity.Itisanescape

routeforstrayelectricity, incasesomethinggoeswrongwiththeapplianceor receptacle.Whenanappliancemalfunctions,acordisdamaged,aconnectioncomeslooseorarecep-tacle is faulty,apersontouchinga liveelectricalcomponentmaygetashock.Thegroundwireprovidesasafepathfortheelectricity,soitdoesnotflowthroughapersontouchingthesystem.

Groundedreceptaclesareonlyusefulforapplianceswithgroundedplugs.Thereareveryfewhomeapplianceswithgroundedplugs.Theseincluderefrigerators,washingmachines,micro-waves,waterbedheaters,somecomputers,somesmallkitchenappliancesandsomepowertools,forexample.Groundedplugsalsocontrolpolarity,sinceapplianceplugscanonlybeputintooutletsoneway.

gFCISASAn A ground fault circuit interrupter (GFCI) on an ungrounded circuit will improve the safety ALTERnATIVE ofthesystem.Manyelectricalauthoritieswillnowacceptgroundfaultcircuitinterruptersas

analternativetogroundinginexistinghomes.GFCIscanbeinstalledatthepanelorasGFCIreceptacles.SomeauthoritiesmaynotacceptGFCIreceptacles.Formoreinformationabouthowgroundfaultcircuitinterrupterswork,see3.4inthischapter.

20-AmP 20-ampreceptaclesareprotectedbya20-ampbreakerandthewiresizefor20-ampcircuits RECEPTACLES is12-gauge,ratherthan14-gauge.20-ampreceptaclesareeasytoidentifybecausethelarger FoRkITChEnS (neutral)slotsareT-shaped.Thesereceptaclesarealsocommoninlaundryareasandbath-

roomswherehigh-currentsmallappliancesarecommon–kettles,toasters,hairdryers,etc.Receptaclesratedat15ampsmaybefoundon20-ampbranchcircuits.

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CommonProblemswithOutlets(Receptacles)

ungRoundEd Where only two-prong appliances are used, this does not pose a hazard. However, wherethree-prongplugs(groundedappliances)areused,theoutletshouldbegrounded.Aspecialgroundwirecanbeadded,butthisisexpensiveandrarelydone.Thegroundfaultcircuitinter-rupterprovidesimprovedsafety,butitisnotquiteareplacementforgrounding.

PooRLoCATIon Outletsshouldnotbeinstalledhorizontallyinfloorsorcountertopsunlesstheyareaspecialtype suitable for this application. Moisture can create an electrical hazard. For the samereason,outletsshouldnotbelocatedoncountertopsurfaces,facingup.

Outletsshouldnotbeclosetoasourceofwaterunlessprotectedbyagroundfaultcircuitinterrupter.Theyshouldnotbedirectlyabovekitchensinksorbathroombasins,forexample,where appliance wires may touch water. Outlets should not be above electric baseboardheatersorclosetootherheatsources,whereappliancewiresmaytouchhotsurfaces.

REVERSEd Modern outlets have a large slot (neutral) and small slot (hot). If the wires are connectedPoLARITy improperly,thisisreferredtoasreversedpolarity.AreversedpolarityoutletcancompromiseouTLETS the safety of an electric appliance. A grounded appliance may have its grounding made

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Withreversedpolarityoutlets,itispossibleforsomeapplianc-estohavetheirhousingbecomelive in the event of a malfunc-tion.Itisalsopossibleforsomeelectricalequipmenttooperateimproperlywithreversedpolar-ity. This may include a homecomputer, a stereo system,etc. Corrective action simplyinvolves connecting the wiresto the correct terminals on theoutlet (black wire to the brassterminal and white wire to thesilverterminal).

numBERoF Thereshouldbereceptacleswhereverpeoplearelikelytoplugthingsin.Innewconstruction,ouTLETS thereshouldbeanoutletwithinsixfeethorizontallyofanypointalongthewall(infinished

livingspaces).Translated,thismeansthereshouldbeanoutletevery12feetalongthewall.Innewkitchens,thereshouldbeanoutletwithintwofeetorthreefeetofanypointalongthecounter.

Olderhomeswillnottypicallyhaveasmanyoutletsasmodernlifestylesdemand.Commonsensesaysthereshouldbeoutletswhereveryouneedthem. Ifyouhave lotsofextensioncords,youneedmoreoutlets.

BAThRoomS Outlets should be within threefeet of basins, but not directlyabove the basin. In modernconstruction,bathroomoutletsshouldbeprotectedbyGFCIs.

LooSE/ As outlets wear, they may notdAmAgEd/ hold plugs securely in place.

WoRn/ Electricaloutletsthatare looseoVERhEATEd or damaged should be re-

paired or replaced. Similarly,coverplatesshouldbereplacedwhen damaged. Where thereis evidence of overheating, aspecialistshouldbeengagedtoinvestigate.

WEAThER-TIghT Specialweather-tightoutletsarerequiredoutdoorsorwherewatermaycontacttheoutlet. ouTLETSnEEdEd

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CoVERPLATE Damagedormissingcoverplatesshouldbereplaced. mISSIng/ dAmAgEd

Won’TWoRk Ifanoutletisinoperative,itispossiblethat: 1. Theoutletitselfisdefective. 2.Thewiresinsidetheboxattheoutletarenotproperlyconnected.(Intermittentproblems

usuallymeanalooseconnection.) 3.Thereisaprobleminthewirebetweenthepanelandtheoutlet(perhapsatanotherbox

upstream). 4. Thereisablownfuseortrippedbreakerinthepanel. 5. Thereisapoorconnectionordamagedwireinthepanel. 6. Thepowerhasbeenturnedoff.

5.2Lights(LuminairesinElectricalCodeTerms)

dESCRIPTIon Installedlightingmaytaketheformoftraditionalceiling-mountedfixtures,recessedlight-ing,combinationlightsandfans,oranynumberorarchitecturaloptions.Thereareseveraltypesoflightingfixturesincludingincandescent,fluorescent,LED(lightemittingdiode)andhalogen.

CommonProblemswithLightFixtures

dAmAgEd/ Damaged light fixtures may present a fire or shock hazard and should be replaced. LightPooRLySECuREd/ fixturesshouldbewell securedto junctionboxes.Theyshouldneverbesupportedby the oVERhEATIng wiring.Lightfixturesshouldbearrangedsothattheyarenotsusceptibletooverheating.Some

fixturesrequireclearancefromcombustiblestopreventoverheating,andsomecanonlybeinstalledincertainorientations.

mISSIng Whenlightfixturesareremoved,sometimesopenjunctionboxesareleftwithlivewiresinthem.Thisisnotsafeandtheboxshouldbecovered.

Lightsshouldbeprovidedforallexteriorentrancedoors,sopeoplecanentersafelyatnight.

Won’TWoRk Inoperativelightsmaybetheresultof–

1.Aburnedoutbulb. 2.Afaultylightfixture. 3.Apoorconnectioninthebox. 4.Aflawinthewiringleadingtothebox. 5.Aproblemwiththeswitchcontrollingthelight. 6.Aproblemwiththewirebetweenthepanelandtheswitch. 7.Ablownfuseortrippedbreaker. 8.Apoorconnectionwithinthepanel.

Iftheproblemisnotsimplyaburnedoutbulborablownfuse,youmayneedanelectriciantoresolvethedifficulty.


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FLICkERIng Flickeringlightsmayindicatedangerousconditionsincludingpoorconnections.TheseshouldLIghTS beinvestigatedpromptlybyanelectrician.

PoTLIghTS Unless they are specially de-(RECESSEdLIghT signed for the application,

FIxTuRES) recessed light fixtures shouldShouLdBE notbe installed inareaswhere

ChECkEd insulation will blanket thefixture, impeding normal heatdissipation. This may lead tooverheating and is a commonproblem on the upper floorof the house. Special fixturestypically have a designationthat includes the letters IC (In-sulation Contact or InsulatedCeiling). These are often notvisibletothehomeinspector.Wherepotlightsareusedinaninsulatedcavity,anelectricianshouldbeengagedtoverifythesafetyofthesystem.

dAmPAREAS Lightsused inareaswhereexposuretowatermayoccur,shouldbeofaspecial type.ThisnEEdSPECIAL includeslightsinshowerstalls,saunasandoutdoorlightfixtures.Again,thehomeinspector

FIxTuRES maynotbeabletodeterminewhetherthelightsareappropriatefortheapplication.

STAIRLIghTIng Light for stairwells, except for unfinished basements, should be switched at the top andShouLdBE bottom.Thiseliminatestheneedtowalkupordownpoorlylitstairs.

ConTRoLLEd FRomThEToP AndBoTTom

hEATLAmP Heat lamps at ceiling levelPRoBLEmS should be located beyond the

swingofanydoors. Ifadoor ispartially open below a heatlamp,atowelorarticleofcloth-ing flung over the top of thedoor can be ignited, causingafire.

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gRoundIng Lightingfixtures,outlets,switchesandjunctionboxesshouldbegrounded.Remember,wemISSIng saidgroundingwasimportanttocarrystrayelectricitytoasafeplace,sowedon’tgetanelec-

tricshock.Homeinspectorsdon’tdeterminewhetherlightfixturesareproperlygrounded.

oBSoLETE Veryold-styleporcelainlightfixtures,usedwithoutelectricalboxes,arenotsafeandshouldbereplaced.Liveelectricalconnectionsareexposedonthesefixtures.

ExPoSEdTo Lightfixturesinclosetsareaconvenientfeature,butthelightsmustbekeptclearofareasmEChAnICAL wheretheymaybedamaged,orwherestoragemaybedirectlyagainstthelightbulb.Lights

dAmAgE shouldnotbeinstalledaboveorbesideshelvingunitsinclosets,forexample.Lightsonthewall above the closet door are usually safe. Incandescent bulbs should be fully enclosed,ideally.

5.3Switches

dESCRIPTIon Switchesmaycontrollights,receptacles,exhaustfansorotherinstalledequipment,suchasfurnacesandboilers.Ideally,lightswitchesshouldbeplacedinareaswheretheycanbeeasilyreachedwhenenteringaroom,orapproachingasetofstairs.

ThREE-WAy Three-way switches are requiredSWITChES inordertocontrollightingfrom

both the top and bottom ofmost stairways. Despite theirname, there are two switchesthat control one set of lights.Theyarealsocommonateitherendsofhallways.

CommonProblemswithSwitches

dAmAgEd/ Damagedorlooseswitchesorcoverplatesshouldberepairedorreplaced.TheoldpushbuttonLooSE/oBSoLETE switches (with two circular buttons which push into the switch and pop out) are gener-

allyconsideredunsafeandshouldbereplaced.ReproductionswitchesofthistypearenowapprovedandavailableinNorthAmericaforthearchitecturalpurist.

ImPRoPER Any switch that works only intermittently or that causes the lights to flicker should beoPERATIon replacedpromptly.


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PooRLoCATIon Traditionally, switches were located about five feet above the floor. Where access for thedisabledisimportant,switchesaretypicallyaboutfourfeetabovethefloor.

Switchesinbathroomsshouldbeasfaraspossiblefrombasins,bathtubsandshowers,ideallyfivefeetormore.

ImPRoPER Stairwelllightingshouldbeswitchedbothtopandbottom. STAIRWELL LIghTIng

SWITChoRCoVER Damagedormissingswitchesorcoverplatesshouldbereplaced. PLATEmISSIng/ dAmAgEd

Won’TWoRk Aninoperativeswitchmaybe:1.Aproblemwithintheswitchmechanism.2.Aproblemwiththeconnectionsofthewireintheboxattheswitch.3.A flaw in the wire between the panel and the switch (including boxes upstream of the

switch).4.Aproblemdownstreaminthecircuitfromtheswitchthatmakesitseemliketheswitchis

faulty.5.Ablownfuseortrippedbreakerinthepanel.6.Adamagedorpoorlyconnectedwireatthepanel.7.Aburnedoutlightbulb.

Anelectricianshouldbecontactedtolocateandcorrecttheproblem.

5.4junctionBoxes

dESCRIPTIon Junction boxes are used to contain and support switches, outlets and lights. They can bemetalorplastic,andcome ina largevarietyofshapesandsizes. Junctionboxesmayalsosimplycontainwireconnections.Junctionboxesnotonlyprotecttheconnectionitself,butsecurethewirescomingintotheboxandholdtheminplace.Allmodernconnectionsshouldbemadeinsideajunctionbox.

CommonProblemswithJunctionBoxes

mISSIng Whereelectricalconnectionsaremadewithnojunctionboxes,thedangerofelectricalshockandfireisincreased.Withtheexceptionoftheearlyknob-and-tubewiring,allconnectionsshouldbeinjunctionboxes.

LooSE Junctionboxesshouldbeproperlysecuredtoframingmembers,andwiresshouldbesecuredto the box, otherwise there is potential for strain on the wires, which may result in looseconnections.

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SPECIAL Specialwater-resistantjunctionboxesarerequiredonbuildingexteriors.Thisappliestoother ouTdooR damplocationsaswell. BoxESnEEdEd

CRoWdEd Everyjunctionboxisratedforacertainnumberofwiresofacertainsize.Whereboxesareovercrowded,thereisadangerofoverheatingandpinchingwires.

noTACCESSIBLE All electrical junction boxes should be accessible for servicing. This means they cannot becoveredbyplaster,drywallorpaneling,forexample.

CoVERPLATE All junction boxes should be provided with cover plates to prevent people touching live mISSIngoR electricalconnections. dAmAgEd

5.5Appliances

Some appliances have special electrical situations or needs. A few of those are discussedhere.

CEILIngFAnS Thebladesofceilingfansshouldbeatleastsevenfeetabovefloorlevelsothatpeopledonotgetinjured.Thefanbladesthemselvesshouldbe12inchesbelowtheceiling.Heavyfansshouldbesupportedindependentlyoftheelectricalbox.

AIR Theoutdoorcomponentofanairconditioningsystemshouldhaveanelectricdisconnectina CondITIonERS weathertightbox.Thismakes it safe forservicementomakesure thepower isoffbefore

workingontheequipment.

gARBAgE The cord for a garbage disposal should be no shorter than 18 inches and no longer than dISPoSALS 36inches.Itshouldhaveadriploopandinmanyareasmustbearmoredcable.

dIShWAShERS Thecordforadishwashershouldbebetweenthreefeetandfourfeetlong.

FuRnACESAnd Thereshouldbeadisconnectswitchwithinsightoftheheatingunit. BoILERS

WhIRLPooL Theseshouldbeprotectedbyagroundfaultcircuitinterrupter.Thepumpmotorshouldbe BAThTuBS accessible. hydRomASSAgE TuBoR CIRCuLATIng BAThTuB


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hrb 4 electrical 2012 8.5x10.875 - carson dunlop

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