Basic house wiring

Search using google with ads

Basic house wiring

Resource: Safe electric wiring

2023

Wire size
Use only 600 volt wire. Lamp cord, extension cords are not rated 600 volt. Use copper wire only. Aluminum wire is fire risk and should be avoided or installed by professional. 30 amp breaker use 10 gauge / 120-240 volt 30 amp outlet can be installed on 30 amp breaker only/ use 10 gauge wire ... cannot be connected to 15-20-40 amp breaker. Orange/ #10 gauge wire, with ground ... 30 amp capacity. Safe maximum: 30 x 80% = 24 amps. Buy: 10-2 gauge/ 30 amp 10-3/ 30 amp Southwire electric tools	Yellow 12 gauge 20 amp 120 volt 20 amp outlet can be installed on 20 amp breaker, but not 15 amp breaker/ use 12 ga wire. ... cannot be connected to 30-40 amp breaker. 1 Yellow/ #12 gauge wire, with ground ... 20 amp capacity. Safe maximum 16 amps. Buy: 12-2 gauge/ 20 amp 12-3/ 20 amp NMB is house wiring UF is underground
50-60 amp breaker use 6 gauge / 240 volt 50 outlet can be installed on 50 amp breaker only Buy: 6-2 wire Southwire electric tools NMB is house wiring UF is underground	40-50 amp breaker use 8 gauge / 240 volt 40 amp outlet can be installed on 40 or 50 amp breaker only Buy: 8-2 wire Southwire electric tools NMB is house wiring UF is underground
Protect wiring from damage Use nipper instead of pliers or screwdriver for removing staples (and nails). Do not damage cable or wires inside cable. -Code says: Cable SHALL BE secured without damage to the outer covering. NEC sec. 336-15 Buy End cutting nippers at Amazon	Electrical tools must be insulated. Always best to disconnect power, but insulation failure, lack of proper grounding, grounded neutral, lack of GFCI, out-of-code wiring, generator operating without transfer switch, and other problems still pose a risk to anyone working on electric power ... even when breaker is off. Buy: Electrician tools kits KLEIN TOOLS Tools kits IRWIN tools KNIPEX Telephone cable knife Low Voltage Mounting Bracket for Telephone

Larger image Single-phase main breaker box found in residential installation Single phase means 2 wires are needed to complete each circuit. Contrast single-phase with commercial 3 phase where 3 wires are needed to complete each circuit. -Electricity arrives in the breaker box after passing through the meter box, and meter. -The breaker box has 4 busbars: 2 Hot busbars, 1 Neutral busbar and 1 Ground busbar that is bonded (connected to) Neutral busbar. Each Hot busbar carries 120 volt electricity that is out of phase... like the pedals on a bike, each phase in either rising or falling but always opposite the other pedal. -When double breaker is installed over two 120 volt out-of-phase busbars, there is 240 volt potential across the 2 Hot wires. -When a single-pole breaker is installed over a busbar, there is 120 volt potential across the Hot wire and the Neutral. -Each 120 volt circuit requires a Hot and Neutral wire. Each 240 volt circuit requires 2 out-of-phase Hot wires but does not require a Neutral. -All 120 volt and 240 volt circuits require ground wire. The ground busbar is bonded to the Neutral busbar, and the Ground busbar is connected to a ground wire that goes to the ground rod driven into the soil outside the house. Resources: Electricity: Generator to power pole Power pole to residential breaker box Power pole to commercial breaker box How to wire commercial 3-phase Difference between single-phase and 3-phase
Larger image Typical 120 volt circuit -Illustration shows typical 120 volt single-phase circuit found in homes and business, passing through walls and ceilings to reach each box. Maximum 12 boxes per circuit. By code, a box should have one Hot wire supplied from one breaker. A box should not have a second Hot wire supplied from a different breaker.
Larger image Typical 120 volt circuit -Illustration shows wiring for switches and outlets, including 3-way switches, in a typical 120 volt single-phase circuit with max 12 boxes. Note that one breaker is used for entire circuit, so that 1 Hot and 1 Neutral and 1 ground wire travels from box to box until the last box is reached. -The Hot wire connects to every outlet, switch, light etc. -The Neutral connects to each outlet and light, but does not connect to switches, unless the switch is a combination with outlet or pilot light. -By code, switches turn the Hot wire on and off. It is against code to turn off the Neutral instead of Hot. -The Ground wire runs continuously and connects to all devices and metal boxes in the circuit. Plastic boxes contain ground wire but ground wire does not need to be bonded to the box. Only the hot wire(s) are switched off. Neutral wire is never switched. The ground is never switched, and never used as a Neutral.
Larger image 120 and 240 volt circuits, plus dedicated circuits -Basic household wiring supplies Hot and Neutral to 120 volt circuits that serve lights, plugs and appliances. -Some appliances, such as microwave and gas water heaters with flue damper or power vent, are required to have dedicated breaker where only 1 item is served by the circuit. -Microwaves are on dedicated circuit because they draw 12-15 amps. -The purpose putting gas water heater on dedicated circuit is to prevent surges and anomalies, caused by other appliances or motors, from affecting operation of gas control valve. -All 240 volt appliances, such as water heater, subpanel, clothes dryer, oven, HVAC etc have two Hot wires and are required to have dedicated double-pole breaker. Buy: Emerson microwaves Resources: How to wire subpanel How to wire Tankless water heater Figure volts amps watts
Larger image How to run new outlet boxes You want 4 new outlet boxes. Use only electrically-rated boxes. Homemade boxes are not rated for the heat and fire hazard. All boxes must have a matching cover. If your wiring is going to be visible, then keep everything straight and looking nice, and boxes same height off floor. Use other outlets as a guide for correct height. For ease of access you can set outlet boxes higher in garage or basement for workbench, washing machine etc, or to avoid flood waters etc. Wire the 4 outlets one after the other until last box has just one romex cable into the box. Metal and plastic boxes are marked on side for drywall thickness. Typical residence with 1/2 drywall, set front edge of box out 1/2" from stud wall so drywall can be installed. Strip back sheathing on cable. Code requires about 1" sheathing inside the box. You have 2 black, 2 white, 2 ground. Give yourself plenty of wire to work with inside box. Strip back insulation on each black and white wire about 7/8", being careful not to score or cut the copper, which can cause weak point and extra heat on circuit. Use needle nose pliers to make a hook so wire can hook around screw on outlet or switch. If you have 20 amp breaker and #12 wire, you can use either 15 or 20 amp outlet or switch. If you have 15 amp breaker and #14 wire, you can use 15 amp outlet or switch, but not 20 amp. 30 amp outlets require 30 amp breaker and 10 gauge wire. Connect 2 black wires to the 2 brass (or black) screws on outlet. No insulation under screw. Tighten screw very tight. Connect 2 white wires to the 2 silver screws on outlet. The hook will go from left to right so hook gets tighter as you tighten screw. The outlet will have 1 green screw for 2 ground wires. Wrap or hook both ground wires around the green ground screw, making sure they cannot come loose or touch the black hot wires or brass screws on outlet. Or use a short and long ground wire. And twist the shorter ground wire around the longer one in the middle, then hook the longer one around the green screw. Or jumper a short piece of ground wire with the other two as shown in illustration. Be sure to push bare grounds down and away from black hot wires and the brass screws on outlet.

Set boxes and panels so they are flush with drywall
Metal and plastic boxes are marked on side for drywall thickness. Typical residence has 1/2 drywall, so set front edge of box out 1/2" from stud wall so drywall can be installed.
This is important so the box cover will fit flat against box without gaps etc.

All panels, boxes, wire, conduit etc must be attached to structrure
For example, nail boxes to 2x4 frame, and not to siding or bare drywall where boxes, wire etc can pull loose. Exception would be old work box. See image
Wires must be located where people cannot walk on them, or equipment impact electrical of any kind.

Indoor panels and subpanels are not weather resistant and can only be installed indoors.. Cover must fit flush against the metal box. Panels and subpanels can be surface mounted to firm structure or mounted between 2x4 studs, and set out 1/2" or 5/8" in anticipation of drywall thickness. Surface-mount must be attached to structure (2x4 frame, concrete wall, electric pole etc), and cannot be mounted to drywall or siding where the enclosure can pull loose. Locate where shop tools etc cannot impact panel.

Outdoor Panels and subpanels are weather resistant and can be used indoors or outdoors. Rated Nema 3R outdoor panels are 'weather resistant' but not 'waterproof.'
Electric panels cannot be attached to mobile trailer unless trailer is permanent and skirted. Attach to nearby pole. Locate 12" above anticipated snowfall. Best in sheltered, shaded area. Avoid direct exposure to sun to maximize efficiency and longevity. Must be attached to permanent structure. Locate panel where equipment (forklift, lawn mower) cannot impact panel. When required by code, steel outdoor panels should be bonded to ground wire that is connected to nearby ground rod.

Resource
How to wire subpanel

Wire connections/
-Use clean wires ... sand off any corrosion, cut back any melted or burned end. Do NOT use damaged wire.
-Always tighten screws and connectors very tight against wire.

-Make hook shape with needle nose pliers when attaching wire to screw terminal.

-Never use stranded wire under screw terminal. Instead crimp on a terminal.
-Straighten wires for lug connection
-Twist wires together very tight so there are no gaps or looseness, and then apply twist-on wire connector, making sure all bare copper is covered, and that connector cannot pull off.
Resource: Safe electric wiring

Larger image
Dedicated circuit
Microwave oven must be on a dedicated circuit since it consumes 12+ amps when operating.

One breaker supplies power to outlet where microwave plugs in.
This is required by code because microwave pulls so many amps.
This is called a small appliance circuit.
New residential homes should have 2 or 3 small appliance (or dedicated) circuits in the kitchen.

Other 120 volt circuit that might require dedicated circuit include window air conditioner, baseboard heater, bathroom heater, whole house vent fan. Anything that consumes a lot of power can be wired to a dedicated circuit.

While ordinary (non-dedicated) 120 volt circuits can have up to 12 boxes, all 240 volt appliances are on dedicated circuit where one double breaker supplies each 240 volt appliance. For example, the 240 volt air conditioner, clothes dryer, water well pump, subpanels, arc welder, water heater are each on a separate circuit. Other appliances might include 240 volt window air conditioner.

Larger image
120 volt controls 240 volt water heater
240 volt circuits can be controlled by 120V using a contactor. This lets you install timer or home automation device to any 240 volt circuit.

Resources:
How to wire Zwave contactor
Project step-by-step
Override air conditioner with timer

Keep timer door closed
Prevent fire inside timer and electrical boxes
Use only copper wire/ never use aluminum wire.
Tighten screws very tight against copper wire.
Match timer rating with Load rating.
Never mix stranded and solid copper wire under same screw plate.
Never mix 2 different gauge wires under same screw plate.
Make sure only copper is under screw plate, and that no insulation is under screw plate.

Always keep timer door closed
Connecting wires with screws
Examples: Outlet, switch, circuit breaker, timer, water heater thermostats.
Resource: Safe electric wiring

Household NM-B Wires are color-coded so inspectors/ electricians can easily identify which wire is used during construction Use only 600 volt copper wire for household wiring Never use aluminum wire or extension cord for permanent wiring	Match wire size and breaker amp rating If your home was wired by professional electrician who pulled permits, then circuit breaker and wire size will match. If manufactured home or travel trailer has not been altered by homeowner then breaker and wire size will match. If wire is too small and breaker is oversized for wire... fire danger Breaker can let too much electricity travel through the wire. Wire can overheat and cause fire. Call electrician if you suspect wiring is not correct. Absolute electrocution danger when removing cover off main panel. The wires on main breaker are hot even if main breaker is turned off. By code, all wire and cable used for permanent installation in homes and businesses must be rated 600 volt. Extension cords are NOT rated 600 volt, instead they are rated for 150-300 volt max, and cannot be used for permanent wiring, or pass through walls, ceilings, floors, or windows, or attached to building surfaces, concealed behind walls etc. The reason: 600 volts is the maximum supply voltage that can be delivered by the grid for typical commercial uses such as sewer pumping station or local shop etc. Homes never receive 600 volt service, and there are no household devices or appliances made for such voltage, but all wire, brealers, enclosures etc are rated minimum 600 volt. Outlets, refrigerators, light bulbs, etc each have a volt rating on the product somewhere. Do NOT exceed volt rating. Resource: How to replace circuit breaker
Single, Double, Triple breakers Single breakers and tandem breakers are used for 120 volt residential, and for single-phase commercial voltages like 120 and 277V. Double breakers are used for commercial and residential voltages like 208 and 240 volt. Triple breakers are used for 3-phase commercial service panels up to 600 volt. Code says: Use connected/ double-pole breaker Against code to use 2 single breakers to supply 240 volt, unless the switches are connected by a bar If double breaker is rated for 30 amp, then BOTH sides of the breaker are each 30 amp (not 15 amp each) Power is doubled with 240 volt vs 120 volt, amps are not halved Resource: What is 277 volt What is 208 volt What is 3-phase See inside Residential electric service Difference 3-phase and single phase
	Circuit breaker and wire size must match Chart on left shows that 30 amp breaker matches 10 gauge copper wire. Do not use aluminum wire. Copper wire is safe. All wire expands when electricity travels through wire. Aluminum wire expands more than copper wire. Expansion causes connection points to come loose resulting in fire hazard. Special compression fittings and CO-AL rated devices must be used with aluminum wire. Image on left shows rating for lengths up to 100' feet for household NM-B and DU-F Resources: Larger image with wire types, temperature, long length Maximum wattage for household NM-B and DU-F wires Wire diameter, weight, resistance

Outlets/ Switches Volt and amp rating for switches and outlets is embossed or printed on the device: If you have 20 amp breaker and #12 wire, you can use either 15 or 20 amp outlet or switch. If you have 15 amp breaker and #14 wire, you can use 15 amp outlet or switch, but not 20 amp. 30 amp outlets require 30 amp breaker and 10 gauge wire. It is against code to connect 20 amp switch to 15 amp breaker ,,, but ok to connect 15 amp switch to 20 amp breaker. Do NOT use 15 amp switch for 20 or 30 amp load. Switches are rated by voltage and amperage. Inexpensive single-pole switch can be rated 120 volt, and can be used for 120 volt only. Better grade switch rated 120-277 volt can be used for residential and commercial 120 and 277 volt. 240 volt switches can be used for 208 or 240V and are typically double pole to switch off both hot wires. A 240 volt load can be switched off using one wire or both wires. Only the hot wire(s) are switched off. Neutral wire is never switched. The ground is never switched, and never used as a Neutral. . Residential switches and outlets are rated for 15, 20 and 30 amp. Single-pole switches have 2 screws and ground screw. 3- way has 3 screws and ground screw. 4-way has 4 screws and ground screw. 4 pole switches have 4 screws but can be differentiated from 4-way by 120-277V rating on 4-pole, and 120V rating on 4-way.
	Single pole switch with No Neutral is considered 'Old school' wiring ... it works correctly, but is no longer code because white wire carries power. Today, all 120v boxes must have Neutral wire. 240v boxes do not require neutral. A ground wire must be present in all boxes. All metal boxes, conduit, switches etc must be grounded. All wiring must be inside a box with cover
	Single pole light switch with Neutral in box. This is correct wiring: every 120v switch box has Neutral Neutral wires are never connected to switch, unless its a combo switch with outlet, or indicator switch. If neutrals are present inside box, then they will be the white wires that are twisted together, covered with wire nut and pushed to back of box. Only the hot wire(s) are switched off. Neutral wire is never switched. The ground is never switched, and never used as a Neutral. Resources: Steps for replacing typical switch How to troubleshoot loose wire, ground fault, or short
Larger image	Single pole switch with Neutral located in junction box Any electrical box can be a junction box... with wires that go to other boxes. Electricall-rated boxes and matching cover required. Neutral wire is never switched on-off Outlet boxes always have neutral wire Switch boxes and ceiling boxes should have neutral wire. Resource: How to wire switches

Outlets are wired in parallel
Electrical switches, timers, outlets, lights etc are always wired in parallel as illustrated on this page.
Wiring in series causes voltage drop the farther you go down the line, so your string of holiday lights get dimmer at end of string.
Parallel wiring ensures that voltage remains the same across entire circuit, so bulbs and loads run correctly. It's just way electricity works.

Notice color code on outlet screws: Brass and Silver. Black Hot connects to Brass screw (often painted black color since modern screws are made of steel instead of brass). Neutral universally connects to silver screw. Both Neutral screws are bonded together so 1 connection point is all that's needed. Brass screws are connected with a piece of metal, and often a break-away fin that can be removed to accomplish various wiring options not shown on this page.

Outlet polarity

The Green Ground screw is always located on the Neutral side of outlet.
Outlets can be rotated either way, with Neutral or Hot on left or right.

Outlet shown is for 120 volt ONLY. DO not use 120 volt outlet for 240 volt.
Outlets for 240 volt are rated for 240 volt, are made to carry more amperage, and have different blade configuration. See image
How to wire 240 volt straight blade outlet

NEC (National electric code)
-120 volt 15 amp devices including GFCI, timers, switches, plugs can be installed on 15-20 amp breaker, not 30-40-50-60+ amp breaker.

-120 or 240 volt 20 amp outlet can be installed on 20 amp breaker, but not 15 amp or 30-40-50-60+ amp breaker.

- 240 volt 30 amp must be installed on 30 amp breaker with 10 ga wire.

Resources:
How to wire 240 volt straight blade outlet
Figure volts amps watts
Color code for wire/ breaker size

120 volt outlets are different than 240 volt outlets
15 amp are different than 20 amp.
Select correct design for voltage and amperage.
DO NOT connect wrong voltage, or risk burning out electrical load.
For example, plugging 120 volt drill into 240 volt plug: the drill will run very fast for a moment and then smoke comes out and drill motor is burned beyond repair. Connecting electronic timer to wrong voltage will destroy timer.

Larger image
Larger image

Twist lock and regular outlets/ Split feed:
Leviton 4794, 4792 and 4795
Use 2 separate wires. 18-10 AWG
Max amperage on each outlet 15A.

Buy:
4794/ 15 amp/ split 125 volt
2 Hot Feeds and 2 Neutral Returns
4792/ 15 amp 125 volt
1 Hot feed 1 Neutral return
4795/ 15 amp/ split 125 volt
2 Hot Feeds and 1 Neutral Return

Resources
How to wire twist lock plugs

Larger image
Single-phase 120-240 volt twist-lock outlet or connector is marked X-Y-W-G or X-Y-G
120V and 240V requires two wires to complete circuit, and ground wire for safety.
120V requires 1 hot and 1 neutral.
240V requires 2 hots.
Neutral is not needed for 240volt electric circuit, but is sometimes included on electrical device, depending on end-user application.
Resources:
See inside main box
Figure volts amps watts
Select correct wire and breaker
Electrical formulas

Z is used for 3-phase and not shown here.
Commercial 3-phase outlet is marked X-Y-Z-G or X-Y-Z-W-G
Resource:
How to wire 3-phase

Install wiring
	Keep wires in center of 2x4s and out of way from any nails. When remodeling, never assume location of existing wires. Use a stud finder to see inside the wall, or cut out small piece of sheetrock to view conditions before nailing. If wire has nail damage, the full length of wire must be replaced from box to box. Concealing a box inside wall is not code.
	Switch boxes are 50" from floor Outlet boxes are 16" from floor
	Run wire down center of 2x4 to avoid nails Apply cable staples to secure wire to 2x4 Set switch or outlet box out from 2x4 to match thickness or drywall Nail staple down snug against wire. Make sure the staple does not cut into the wire. The wire should not be able to move after staple is applied. Staple is not nailed down hard... just snug. Keep wire in middle of 2x4 wall. Staple wire every 3 feet or so.
	Protect electric wires from nails Apply metal plates over places where wire passes through 2x4 Drill hole through middle of 2x4
Boxes cannot be concealed inside walls. All boxes must be accessible and readily visible for inspection and repairs as needed. If a junction box is absolutely necessary behind a wall, then cut opening in drywall, set box for thickness of drywall, set the box flush with finished wall surface, and then install hardwired or battery-operated smoke detector over top of box. Another possible solution is to use a rectangular wall box, and install blank plate over the box. Buy Smoke detectors
If another wire already drops through top plate where you want your wire, see if your wire will push through same hole. If you have to drill, move over several inches from other wires so drill won't contact wires. When drilling through top plate 3 things may occur: 1.) You may hit a nail > drill another hole 2.) You may hit top of upright 2x4 > drill another hole 3.) You may drill into the wrong cavity > that's why you drill through top plate before cutting hole in sheetrock Tip: after drilling hole in top plate - and - before cutting hole in sheetrock, drop your wire into wall and have helper rattle it around to make sure you're in the right spot. Put timer at eye-level so it's easy to program.
Do not put anything on top of wires. Plywood, household items, carpet etc pose hazard. Do not set items on top of cable or wire. Do not step on cables or wires. Any movement or pressure on cables or wire can fray insulation, cause damage, short circuit and fire. Drill holes through boards, and re-rout cables. Run cables or wires through conduit, and then add spacers so plywood cannot touch. Code Attic "Unprotected cable SHALL NOT BE installed within 6 feet of an attic access nor within 7 feet of a permanently installed attic stairway. NEC sec. 336-13"
Instructions: Drop wire from attic before cutting hole for box. Once wire is dropped down inside wall, have helper rattle wire around. Noise from wire will confirm location to cut hole. Helper pulls wire up out of way so saw will not cut wire. Cut 2-1/4" x 3-3/4" hole in sheetrock using knife or saw Reach in and find electric wire inside wall Pull electric wire through hole Feed wire into box Set box into hole Turn screws so pop-up fin tightens against inside of sheetrock Install switch. Resource How to install old work box

Wire connections
	How to test for Hot and Neutral wire: Turn power off Separate all wires for testing except ground wires. Turn power on. Tape tester leads to wood sticks for safety. Keep hands away from power. Test each wire to bare ground wire. Tester lights up on Hot wire. Hot wire should be black (except 3-way switches) Test Hot wire to all other wires except ground Tester lights up on Neutral wire. Buy: Voltage neon testers Electric testers
	Outlet polarity on outlets Hot and Neutral must be correct on outlet Hot wire connects to brass-colored screw Neutral wire connects to silver-colored screw Ground wire connects to green screw Resources: How to add a switch How to add outlet

Twisting wire
Use Linesman pliers

Buy tools:
Wire strippers at Amazon
Linesman pliers
Utility knife at Amazon
End cutting nippers at Amazon

Resources:
How to twist wire

	Wire connectors Solid copper wires do not need to be twisted together, but I recommend twisting wire to ensure strong permanent connection. If wires are twisted, then make sure the two wires are twisted very tight. To install connector, turn wire connector very tight against copper When finished, ask two questions: Does connector cover past the copper wire? Yes Is connector tight enough that it will never fall off? Yes Will the wires pull out of connector? No Answer 'yes' to first two questions, and no to last question, you have right connector, and connection is secure.
	Connect light fixture Cut stranded wire longer than solid copper, then wrap stranded around copper before applying wire connector. Do not reuse old connectors Buy: Connector assortment at Amazon Connector assortment at Amazon Resource How to select and install twist-on wire connectors
Light fixtures Use octagon (and round) boxes for ceiling and wall mount lights and fans. Do not use switch box, or non-electrical rated enclosure. Use attachment bracket to secure light to box, then attach box firmly to structure. Round old work box is attached to drywall and is satisfactory for many light fixtures, but not strong enough to support fans, chandeliers etc Watt rating and light fixtures Do not exceed watt rating of light fixture. Typical indoor light fixture usually has maximum 60 watt rating per bulb. Recessed light might be 75W or 150W, and have a thermal reset to reduce overheating. Outdoor aluminum lampholder is 150W. Indoor ceramic lampholder can be 600 watt, as shown on back of lampholder. Image Watt rating is confusing when CFL, LED etc shows equivalent wattage. Not actual wattage. The watt rating on light fixtures was established for heat produced by incandescent bulbs, but still applies to newer style bulbs ... so refer to actual watt Code ''Device boxes SHALL NOT BE used for fixture outlets. NEC sec. 370-27'' Buy: Light fixture attachment bracket brace for ceiling fan round old work box
Light bulb in closet or attic can cause fire -120 volt attic lights and closet lights should be located away from storage. -Cardboard, paper and other flammables stored near a light bulb is fire hazard. -Solutions: Change to LED bulb, move storage, move electric away, change to battery operated light. Install door switch so light turns on-off when door open-closes. High heat light bulbs can discolor fixtures. Fixtures can be spray painted ... BUT ... do not use high heat bulbs afterwards or could be fire hazard. Convert to LED. Halogen bulbs burn hot just like incandescent. Resource: How to move ceiling light
To meet maximum LEED energy conservation: ''All exterior lighting must be Dark Sky qualified and have motion sensor controls, integrative photovoltaic cells, photosensors, or astronomic time-clock operation.'' Emergency and safety lighting are exempt.

Each box, enclosure, panel or connection point requires electrically rated cover.
The cover must be electrically rated to withstand the heat potential of short circuit.

The cover must fit tight onto the box so no spark can exit the box and create fire.
If the box is not flush with wall, the cover will not sit tight against box, leaving space for spark to exit box.
Use a box extension ring so the box will sit flush with finished wall or sit out farther than finished wall.
Box covers must be kept in place and closed.

The cover must be made to fit the box, enclosure or connection.
Using ordinary household box for electrical connections is hazard and not code.
Household boxes made of plastic are a fire hazard. Home-made aluminum, sheet metal and steel enclosure must be sealed equal to electrically box, and all metal enclosures must be grounded.

A light fixture or fan is approved cover. The light or fan etc must sit flat against the ceiling or wall box. Outdoor fixtures must be used for outdoor installations. Using indoor light fixture in an area that gets rain, snow etc is a hazard.
The light must be made to withstand heat of electrical short and heat of the anticipated light bulb. Using a homemade plastic light fixture for 120-240 volt installation is fire hazard.

Hazard: Do not add a vent fan to ventilate heat from any enclosure. All electrical enclosures must be sealed against rapid air penetration that would support a fire.

Buy
Tools
Milwaukee
DEWALT
Black and Decker
Stanley
SKIL
Makita
Porter-Cable
Bosch

Irwin Hand tools
Klein hand tools
Fluke electrical testing
Dremel hobby tools

Campbell Hausfeld air powered
Tekton automotive

Powerbuilt automotive
Saws and saw blades

Buy from my affiliate links every time/ thanks:
Amazon
''As an Amazon Associate I earn from qualifying purchases''
Enter Amazon from any link on my site, fill cart with any item ... purchases pay small commission

E-mail: geno03245w@gmail.com
My response might end up in spam folder, check email folders
Waterheatertimer on Twitter
Message thru facebook