Fishing aReceptacleIntoa Wall Section
Description
Once a househasbeenbuiltandfinished,it’smuchmore difficult for electricians toinstallmoreelectrical devicesinto walls.Manyhomeowners wantto dominorrenovationsandaddreceptacles,switches,andlightstotheirexisting electrical installations.Manyofthoserenovationsaresmallerin scale anddon’trequireremovalofwallsand drywall. Thisis a
situationwhereelectrical workers do installations with minimalconstruction anddisruptions tohomeowners.Fishing a switch,light,receptacle, or another electrical deviceintoanexistinghome is a faster,more economical waytoadddevices or circuitsto a home.Theterm fishing,whenusedwithregardto electrical work,meanstopull cable throughinaccessiblespaceswitha fish tape (Figure2). A fish tape is a very longmetalstripwith a hook attheend,which can beusedtograb a wire or anotherfishtape,somewhatlikecatchingfishwith a hook on a line. Mostoften fishingwireisdonein a finisheddrywallwall.
Fishingwiresintowallsrequiresthe electrician to tap intoexistingpowersourcesandfindtheleastinvasivewaytodoso.Theskilloffishingwiretakestimetomaster.Eventhen,therearealwayschallengestoovercome.Manysmall electrical jobsinvolveonlyoneelectrician.Beingabletofish a wirewithouthelprequires good techniqueandskill. As willmanytasks, practicemakesyoubetter.Therearemanydifferent scenarios forfishingwirein a home. A receptaclemightneedto be fished vertically through a wall,horizontallyinto a lightfixture, or betweenfloors in a house. A wirefishing job will be madeeasierbytakingthetimetoinvestigatethelocation ofthestudsandjoistframingofthehouse.
LessonOutcomes
The student willbeableto:
•Fish a wire intoavertical wall space toadd a receptacle
•Knowhow tolocate studs in a wall
•Worksafely from a stepladder
•Cutaccuratelythroughdrywall
Assumptions
Allstudents:
•Knowhowtousehandtoolssafely
•Knowhowto stripwire
•Understandbasicbranchcircuitwiring
•Havebeen trained in stepladder use
•Knowhow touse atapemeasure and torpedolevel
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Terminology
Drywallorkeyholesaw:ahandsawusedtocreateholesandcutoutsindrywallpanels.
Figure1—Keyholesaw
Fishtape:atoolforpullingcablesthroughinaccessiblespaces.Afishtapeisaverylongmetalstripwithahookattheend,whichcanbeusedtograbawireoranotherfishtape,somewhat likecatchingfishwithahookona line.
Figure2—Fishtape
Flange:anedgeprojectingfromanobjectthatisusedforstrength,forguiding,orforattachmenttoanotherobject.
Joist:alengthoftimberorsteel supportingpartofthestructureofabuilding,typicallyarrangedinparallelseriestosupportafloororceiling.
Plumbbob:aweight,usuallywithapointedtiponthebottom,thatissuspendedfromastringandusedasaverticalreference line, orplumb line.
Figure3—Plumbbob
Reworkdeviceboxes:device boxesusedforinstallationintoan existingwall.Usedinconjunctionwithdevice box supportclips, they are inexpensive and easy toinstall.
Figure4—Support clipsandreworkdevicebox
Note:Therearea few differentmethodsforattaching boxes whenaddingdevices.Boxes may beaddedtoastudorattachedtodrywallbetween studs. Eachelectricianwill likely haveapreferredmethodand box stylethat they use. It’s importantforelectricianstoknowhowtoinstall boxes
in existing wallsusingdifferentmethodsandtypesof boxes. For this activity, themethodwillbeexplained usingaspecifictypeof box. Iftheteacherpreferstouseanothertypeof box orwouldlike tointroducea few differentmethods,thestudentswillbenefitfromexperiencingallofthem.
Figure5—4×2⅛octagon / Figure6—FinishedsurfaceEZ box / Figure7—Loomex2¼"reworkdevice boxStud:anuprightsupportinthewallofabuildingtowhichsheathing,drywall,etc.,areattached.
Studfinder(alsostuddetectororstudsensor):ahandhelddeviceusedtodeterminethelocationofwoodandmetalframingstudsinlight-frameconstruction,afterthewallsurfacehasbeeninstalled.Therearedifferentmodelsranginginpricefrom$20to$60.Somepeopledonotusestudfindersand prefer differentmethodsoffinding studs.
Figure8—Studfinder
Topplate:amemberontopofastudwallonwhichjoistsresttosupportanadditionalfloorortoformaceiling.
Torpedolevel: aninstrumentdesignedtoindicatewhetherasurfaceishorizontal (level)orvertical(plumb).
Figure9—Torpedo level
EstimatedTime
1–2hours
RecommendedNumberofStudents
20 maximum,based on BCTechnologyEducators’ Best Practice Guide. Students canbedividedintopairs or groupsoffourdepending on materialsavailable.Students could dothisactivity inpairswhileotherstudentsareworking on otheractivities.Pairs could then be rotatedthroughthestation.
Facilities
Technologyeducationshop or similarenvironment
Tools
•Fishtape
•Plumb bob
•Linemanpliers
•Needle-nose pliers
•Drywallsaw
•Torpedo level
•Tapemeasure
•Electrical tape
•Robertson®#1 and#2 screwdrivers
•5 or 6'stepladder
•Wirestrippers
•Utility knife
•Smallflatheadscrewdriver
•Pencil
•Hardhat(forladderclimb)
Materials
Tooptimizethisactivity, a section ofwallatleast8'tall×32"wideshould be provided.Thewallsection may be widertoallowmorestudentstocut access holesandtopractiseusingthe
studfinder.Thewall section musthave½"drywall attached tothefrontsideand some sortofbacking on theback(drywall,plywood).Studsshould be installedat16"centres. A falsewall could be builtandtemporarily attached toanexistingwallin a shop or outsidewall, or atemporary free-standing wall section with supports could be built.Ensurethewallis properlysupported andthatstudentswill be abletofishwiresintothewall.Theteacherwillhavetodecidewhatwill work in his or her classroom/shop environment.
Getting studentstocutan access holeandclimb a laddertofishthewiresis crucial fordevelopingtheskillsneededforthisactivity.
Othermaterialsinclude:
•14/2plastic-sheathedcable,20' (7 m)
–Tradename:Loomex
–CECname:non-metallicsheathed cable (NMSC)
•Reworkdeviceboxwith support clips, or teacher’spreferred style ofbox
•Duplexreceptacleandwallplate
Optional
Use a shorter wall section toperformthisactivity.Ifitisnottothedimensionsrequired,itwillatleastgivestudents some practice infishingwiresinto a wall.
Resources
FishingElectricalWireThroughWalls
DIYRunningNewElectricalCable
Activity
1.Theteachershoulddemonstratehowtoperformthisactivity,keepinginmindladdersafety.Ifladdersafetyhasnotbeendiscussed or demonstrated,itshould be donebeforecommencingthisactivity.
2.Theteachershouldshowstudentshowtouse a studfinder on thesamplewallto mark studlocations.Theheight from the floor tothe bottom ofthereceptaclewill be 12"(30cm), sothisistheheightat which thestudsshould be marked on thewall.
3.If a studfinderisnotused,anothermethodtofindthestudsisto tap on thedrywallinvarioushorizontal locations withthehandleof a screwdriver or pliersandlistenforsoundchanges.Whentapping on a hollowwall(awallwithoutinsulation),thesoundshouldchangewhenthestudislocated.
Whenthestudislocated,make a light mark with a pencil,andthenmeasure16"horizontallytolocatethenextstudand mark it.Verifywiththestudfinderthatthenextstudhas beencorrectly located.
4.Once studshavebeenlocatedandmarked,measureand mark tothecentrebetweenthetwostudsat12"(30cm) from thefloor.
5.Using a stepladder,climbupto a heightwherethetopofthewallmay be reached.
Note: Do notstand on thetoptwostepsoftheladder.Make surestudentsunderstandthesafetyissuesinvolvedinusingladders.
6.Once in a good positiontowork,thereare a fewdifferentmethodstotransferthecentre
ofthestudspace mark tothetopofthewall.Thewallinthis activity isnot a full-width wall,soitshould be easyto determinevisuallywhere themark should beplaced.Thisisnotalwaysthe case whenfishingwalls, so studentsshould be shownhowtotransferthe markbyothermethods. A good methodistouse a plumb bob andhangitdown from thetopofthewalluntilitlinesupwiththecentre mark atthebottom.Ifthismethodisused, mark thewall space at the topwhen theplumb boblinesupwith thebottom mark. Anothermethodistomeasure from a pointofreference(suchas a corner)tothe mark atthebottom,andthentransferthat mark tothetopofthewall.
7.With thedrywallsaw,cutan access hole inthedrywallatthetopofthewalljustbelowthetop plate. Access should be roughly 3×3"(8×8 cm).
Note: When cutting pieces outofdrywallthatwill be replacedlater,make suretocutneatsquare or rectangularshapesforeasierrepairlater.
8.Mark outthe hole forthereceptaclebox.Use a tape measureto check thatthepencilmark isat12"(30cm)abovethefloor. With a torpedolevel,make a 2"(5cm)horizontalmark toreferencewiththereworkdevicebox.Placethe bottom ofthebox on the mark
withtheopensideoftheboxagainstthewall.Placethetorpedolevel on thetopofthebox,ensuringthe bottom oftheboxis on the12"mark.Whentheboxislevel, press theboxfirmly againstthewall so itdoesn’tmoveand trace allfoursidesoftheboxontothe drywall.
Note: Do not trace theflanges on thetopand bottom ofthe box.Just trace therectangularshapeofthebox.
9.Whentheshapehasbeentraced,cutthedrywallwiththedrywallsaw.Beginthecutbygentlytappingthetipofthesawintothe drywall. Thencarefullyandaccuratelystart cuttingtotheoutsideofthelinesuntiltheplaceofdrywallisdetached.
10.Beforemountingthebox,loosenthesmallscrewsintheflangesatthetopand bottomoftheboxandpulltheflangesouttothe farthest pointtowardtheopensideofthebox.Retightenthescrews.Adjustingtheflangesallowstheboxtositlevelwiththe drywall.
Withoutadjustingtheflangestheboxwillsitpastthelevelofthe drywall. Thisproceduremust be donebeforeputtingtheboxintothewall.
Figure10—2½" deepLoomexdevicebox
11.Itistimeto fit thebox.Therearescrewholeplatesatthetopand bottom ofthebox,usedto attach a faceplatetotheboxwithscrews.Thedrywallwillneedto be notchedslightlywiththedrywallsawtoaccountforwherethescrew hole platesarepositioned. Once allcutsarecomplete,gentlypushtheboxintothecutoutsection.Whentheboxispushedallthewayin,itshouldsitlevelwiththe drywall. Iftheboxextendspastthe drywall, trim thecutoutwiththesawuntilthebox fits correctly.Whentheboxis fitted correctly,removeitfrom thewall.
12.Nowfishthe cable intothewall.Climbtheladderand insert thefish tape intotheupperaccess point. Feed thetape downthe wall and haveastudenttry to capturethe tapeatthereceptaclecutout.Itmighttake some practice toalignthe tape withthe bottom cutout.
Patienceandcommunicationbetweenthetwo people is important. Ifthefish tape travels
tothe floor itwillneedto be broughtbackupslowlytothecutoutopening. Occasionally theperson atthe bottom willneedtomake a hook with a scrap piece ofwiretocapturethefishtape.Whenthe person atthereceptaclecutoutsecuresthefishtape,pullabout2'(60cm)of tape throughtheopening.
13.Theteachershouldchangepositionswiththestudentatthereceptaclecutout so theteachermaydemonstratehowto attach wiretothefishtape.
14.Measureenough cable toallowfor1'(30cm)ofextra cable atthereceptacleand2–3'(60–90cm)atthetop access point. Strip 8–10"(20–30cm)ofsheathing from the14/2cable. Strip about2"(5cm)ofinsulation from theconductors.Runallthree cables throughthefish tape hook andbendthemback on eachotherto form a stronghook. Hook onlythestrippedportionofthe cables. The attached wiresshould be nolargerthanthe14/2 cablesheathingwidthwhencomplete;makesurethewiresarenotbunchedup.Wrap electricaltape overthebentwirestopreventthem from becoming disconnected.
Agoodconnection between the wires and the fish tape is needed so the cable does not getcaughtupwhenpullingthe cable up,and so thatitdoesnot become disconnected from thefishtape.Manywallshaveinsulation,pipes,andotherobstructionsinthem, so a smallandsturdy connection betweenwireandfish tape isbest.Ensurethe electrical tape wrappedaroundthefish tape hasnosharp or bluntedges;this could be a pointforthe connection togetcaughtupwhendrawingthe cable throughthewall.It’swellworththeefforttoensure agood jointbetweenthefish tape andwireismade so thefish tape doesnot come off.
15.Havethestudentatthetopoftheladdergentlypullupthefish tape whiletheteacherfeedsthe cable intotheopening.Continueuntilthe cable comes outatthetop access
point.Leaveenough cable toallow8–10"(20–30cm)ofwireforwiringthereceptacle.Thestudentatthetopoftheladder can cutoff(withpliers)the cable connection close tothefishtape.Cutthecable,notthefishtape.Make a loop of cable atthetopandput a wrapofelectrical tape aroundittoensureitdoesnotfallbackdownthroughthe access point.
16.Atthereceptacleopening,removethe tab from thedeviceboxtoallowthe cable to bebroughtintothebox. Strip 8"(20cm)oftheoutersheath from the cable withoutdamagingtheconductorinsulation. Insert thestrippedendofthe cable intothebox.Makesurethesheathingenterstheboxandissecuredinplacewithnomorethan½"(1cm)ofsheathinginthebox.Runthebondingwire clockwise aroundthebondingscrewandtighten.
17.Insert oneofthebox support clipsintothereceptacleopeningwiththetwoopenwingsfacingoutward. Hold oneofthewings so theclipdoesnotfallintotheopening. With yourotherhand,placetheboxintotheopening.Whenmovingtheboxintoposition, hold thewingoftheclip so itstaysinplace.Whentheboxisinplace,bendoverthewingoftheclip so itsitsinsidethebox.Use needle-nose plierstosqueezetheclip so itsitstightlyinsidethebox.Thenextclipwill be hardertoplace.Startbypushingoneendinfirst.Theotherendoftheclipwillnot fit intotheopeningbecauseitistoolong.Using a smallflatscrewdriver,gently tap thelong vertical pointoftheclipuntilitmovesthroughthedrywallandpasttheboxintoposition.Squeezethewingsintopositioninthesamewayas on theother side.
Figure11—Reworkdeviceboxsupports
18.Installthereceptacle,makingsureitsitslevelwiththe drywall. Installthereceptacleplate.
19.Removethereceptacle,box,clips,andwire.Theclipsshould be ableto be straightenedandusedagain,andthewiremay be usedagainaswell.
20.Theteachermay choose whethertousethesame access pointsforallstudents or tocutdifferent accesses foreachgroup,depending on resources.
21.Checkforunderstandingandstartstudents on theactivity.
EvaluationGuidelines
Thestudent:
•Workssafelyandresponsibly
•Workssafely on a ladder
•Performs the activity competently
•Uses tools appropriately
•Produces quality workmanship
ExtensionActivity
•Students could attempttodothis activity withoutthehelpof a partner.
•Theteacher could addinsulationbatsinto a section ofwalltomakethefishing activitymorechallenging.