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Basic house wiring
How to wire devices, and how electric devices work/pdf
main breaker box
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Single-phase circuit breaker box
-Electricity arrives in the breaker box after passing through the meter box, and meter.
-The breaker box has 2 Hot busbars and 1 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 How 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.

Generator to power pole
Power pole to residential breaker box
Power pole to commercial breaker box
How to wire commercial 3-phase
  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 cannot have Hot wire supplied from another breaker.

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.
Three phase electric
Difference: single-phase and 3-phase

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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.

-The Neutral connects to each outlet and light, but does not connect to switch. The Hot wire is connected to each switch and each outlet, and runs to each light. Ground wire runs continuously and connects to all devices and metal boxes in the circuit.

Three phase electric

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120 and 240 volt 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.
Emerson microwaves
How to wire subpanel
How to wire Tankless water heater
Figure volts amps watts
Volt and amp rating for switches and outlets is printed on the device:
Do NOT use 15 amp switch for 20 or 30 amp load.
Residential switches 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.
Residential outlets are rated for 15 and 20 amp, with both 120V and 240V ratings.   How electric devices work .pdf
Residential 30-50 amp outlets are larger, and used for dryers and range etc. How to wire 240V outlets
Outlet polarity
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Select correct wire and breaker
Figure volts watts and amps

Yellow 12 gauge 20 amp

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12-2 gauge/ 20 amp
12-3/ 20 amp
Rolls of stranded wire

Orange 10 gauge 30 amp

10-2 gauge/ 30 amp
10-3/ 30 amp
Southwire electric tools

NMB is house wiring
UF is underground
6-2 wire
50-60 amp breaker use 6 gauge

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6-2 wire> Southwire electric tools
NMB is house wiring
UF is underground<

6-2 wire
40-50 amp breaker use 8 gauge

8-2 wire
Southwire electric tools

Copper ground wire

Spools of ground wire
Ground rods at Amazon

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120 volt controls 240 volt water heater


How to wire Zwave contactor
Project step-by-step
How to replace circuit breaker
Choose correct breaker and wire size
How to add subpanel

Outlets are wired in parallel
Electrical switches, timers, outlets, lights etc are never wired in series.
Wiring in series causes voltage drop across the line.
Parallel wiring ensures that voltage remains the same across entire circuit.

Notice color code on screws. Black Hot connects to Brass screw (often black color since modern screws are frequently 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 also bonded together, but often they are connected with a breaker-away fin that can be removed to accomplish various wiring options not shown on this page.
Outlet shown is for 120 volt ONLY. DO not use two-vertical-slot outlet for 240 volt. Outlets for 240 volt have different blade configuration.
How to wire 240 volt straight blade outlet

The Green Ground screw is always on the Neutral side of outlet.
Outlets can be rotated either way, with Neutral or Hot on left or right.
This illustration shows Hot right, Neutral left. Illustration above shows the same.
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 outlet to 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 or two and then smoke comes out and drill motor is damaged beyond repair. Connecting electronic timer to wrong voltage will destroy timer.

How to wire 240 volt straight blade outlet
Figure volts amps watts
Color code for wire/ breaker size
How to wire surge protection
How to wire subpanel
How to wire 240 volt outlets
How to wire GFCI and AFCI
How to wire Combo switches
How to wire Tankless water heater
How to wire under counter water heater
surge protector
Surge Protection is a consumable product that absorbs irregular voltage and protects circuits from damage.
How to wire surge protection

Subpanels are used to expand electric service by adding more breaker spaces
How to wire subpanel

240 volt outlets are used for window air conditioner, RV hook-ups, electric car, dryer, range welder etc
How to wire 240 volt outlets
GFCI breakers and outlets trips faster than ordinary circuit breaker to protect from shock caused by short circuit. AFCI does the same plus trips when a spark is detected.
How to wire GFCI and AFCI

Under counter water heaters are used to provide hot water to smaller consumption areas or to supplement or replace main water heater.
How to wire under counter water heater

Electric Tankless water heaters are used as main water heater, or as supplement to supply one area.
How to wire Tankless water heater

Switch-outlet combos require a Neutral wire and are often used to replace ordinary outlet or switch.
How to wire Combo switches
How to replace outlet with combo switch

Pilot light switches and outlets are used to indicate when a circuit is ON or when a device has power.
How to wire pilot light switch

How to wire switches
How to add a switch
How to add a 3-way switch
How to wire safety switches
How to wire occupancy switch
How to wire transfer switch
How to wire door switch
Control motor with two switches

Circuit breaker box

Basic extremely detailed electric book at Amazon
Basic electric book

Or learn about basic household electricity... use and search my site/ Resource:
See inside main breaker box

What is 3 phase
How to find ground fault in household electric circuit
A ground fault is when Hot electricity reaches the ground wire or the earth, causing breaker or GFCI to trip.
Symptoms include tripped GFCI that will not reset.  In this case, the GFCI device might be bad. But if the GFCI is recording a fault, then troubleshooting is required to find the loose wire, bad connection, defective electrical device, melted motor winding etc.
The GFCI will trip with the slightest fault current, and reacts much more quickly that circuit breaker. The GFCI reacts to a difference in current between wires, while a circuit breaker reacts to heat build-up on the Hot wire. As a consequence, circuit breakers are slow acting, and often will not trip with a slight trickle of power to ground.
If the circuit is protected by AFCI instead of GFCI, then the circuit has additional layer of protection. AFCI will trip if an 'arc' is detected. The arc does not have to reach ground wire, it can merely be a loose Hot or Neutral located on a switch screw, outlet, fan motor etc.
How to wire GFCI and AFCI devices
Difference between surge protector and ground
If circuit does not have GFCI or AFCI, then the short circuit must reach the ground wire and go to earth before the breaker will trip. This emphasizes the need for proper ground wire. Breakers trip for other reasons, such as bad breaker or undersized wire for the load. The breaker trips when heat on the Hot wire exceeds breaker rating. What happens is the fault current pushes electrons down the ground wire out to the ground rod and into earth. The difference in electrical potential between charged electrons on the wire and electrons in the earth creates a strong attraction. Electrons pour down the ground wire uncontrollably trying to equalize the difference in charge between wire and earth. The number of electrons quickly exceed the rating of the wire, the wire gets hot, and breaker responds to the heat by tripping.

Understanding the wires
There are a maximum 12 boxes per circuit.  Dedicated circuits for 240 volt appliances, and 120 volt microwaves, have 1 connection and not 12.
How the wire is routed in the circuit. The 14-2 or 12-2 cable leaves breaker box and travels to the first junction box. For example a ceiling box in the nearest room is normally the first junction box. From the ceiling junction box, the cable splits off, and travels to each of the other boxes in the circuit. Any box can be a junction box where the circuit splits and carries power to another box. So a junction box can have several cables.
For example, if the first junction box is bedroom ceiling box, there will be cables that travel to other boxes, and one cable might travel to next bedroom ceiling box. And so the next bedroom also has a ceiling junction box.
But each box in the circuit will have only 1 cable that connects back to breaker box.
When the cable arrives inside a duplex outlet box for example, another wire will leave the outlet box and travel to the next outlet box, and then travel to next outlet box or next switch box, until the last box is reached.
So each box will have 1 or more cables, and the last box will have just 1 cable.
However, each box has only 1 hot wire, and 1 neutral, and 1 ground that connect back to breaker box.

Finding the fault
First step is to isolate exactly what boxes are on the circuit.
1) Unplug all lamps, clocks, appliances, cords, clocks etc on the affected circuit. Try to reset the breaker or GFCI.  If power is restored, then one of the plugged-in devices is suspect. Wait for a while to see if power continues uninterruped. Reconnect each device one by one to eliminate the good ones. If a lamp is causing the problem, then plug a good lamp into same outlet and see if problem comes back. If problem resumes with good lamp is plugged in, then turn off power and inspect wiring on outlet, and or replace outlet. Quick connection points on back of outlet fail frequently with cheap electrical devices.
2) If problem does not appear to be a plugged-in device, the switches are next suspect. Turn off all ceiling fans, lights, and switches. See if GFCI or breaker resets. If power resumes, then turn each switch back on one by one.
If ceiling fan causes problem, remove, inspect, replace switch and see if problem is solved before replacing ceiling fan.

If problem is inside the wiring somewhere:
3) Select one of the outlet boxes with more than one cable. Identify which cable has the Hot and Neutral. Disconnect the other cable so boxes farther from breaker are disconnected from the circuit. Turn power ON, and see if fault is still present.
If fault is still present, then choose another live box that has two or more cables that is closer to breaker box, and repeat test.
Process of elimination will narrow the search. Sometimes it is easier to replace all the switches, outlets and wire connectors in a room, but that is no guarantee the problem will be solved. Other causes can be rodent damage to wire, nail in wires, cable staple in wire, or some other wire damage.
Dedicated breaker for microwave ovenLarger image

Dedicated circuit
Microwave oven must be on a dedicated circuit
One breaker supplies power to outlet where microwave plugs in
basic electric 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.
Basic household electric wiring Switch boxes are 50" from floor
Outlet boxes are 16" from floor
Basic household electric 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 Protect electric wires from nails

Apply metal plates over places where wire passes through 2x4

Drill hole through middle of 2x4
Test wires electric tester
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.

Voltage neon testers at Amazon
Electric testers at Amazon
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

How to add a switch
How to add outlet
Remove cable staple Use end cutting pliers to remove staple & nails
Good tool for electric work and construction
front cutting pliers
Crescent-brand end cutting nipper at Amazon
End cutting nippers at Amazon
Linesman pliers Linesman pliers
Use to twist wire
Use to cut wire
linesman pliers
Buy tools:
Wire strippers at Amazon
Linesman pliers
Utility knife at Amazon
End cutting nippers at Amazon

How to twist wire
strip wire Carefully slice through coating on wire
Cut down middle of cable over the ground wire
Use sharp blade
Utility knife
Utility knife at Amazon
Wire stripper
Terminal crimp tool

Wire strippers at Amazon

Color code for wire
circuit breaker Circuit breakers
Water heater is tripping breaker
How to replace circuit breaker
How to wire gfci
Can AC breaker be used for DC breaker
How to reset circuit breaker
Not enough space for circuit breakers
Circuit breakers
How to install subpanel
Why you need ground wire
Match breaker and wire size
How to wire subpanel
See inside breaker box
How to wire safety switch
How to wire whole house surge protector
circuit breakers are warm                       Water heater blowing breaker
Move wires to different same-size breaker and see if problem continues


Stress test breaker panel
How to replace circuit breaker
Color code for wire
Bond solar panel to ground rodGround wire
All phone, satellite, pool equipment, solar systems and electric panels must be grounded. Check local electric codes.
What does this mean? Bonding is the connection of metal to a ground wire that is in turn connected to a ground rod driven into the earth to a depth that meets local codes for grounding. Drive ground rod 8-10 feet into soil. Bond #6-8 bare copper wire to ground rod and to solar panels and pipes on roof.
Do NOT ground electric system to water pipes. Ground must be connected to ground rod. Stray current corrosion can cause pipes to deteriorate. Uncertain bond to ground because of plastic pipes.
Ground rod and clamps at Amazon
Bonding lugs
Bond all ground wires together to help prevent surge & lightning damage. Bonding all grounds together will help prevent damage from lightning strikes beyond 100' away...
Strong lightning strikes within 100 feet must be handled by lightning rod
Local code requires bonding: this includes all ground rods for satellite, TV, phone, solar, electric panel, subpanels (within 100 feet) etc must be connected together and bonded to main electric panel ground rod driven into soil at correct depth to meet local code. Consult local electrician.
Codes for grounding depth vary: loose rocky dry soils are less conductive than dense wet soils
No system other than lightning rods will protect against direct lightning strike or strike within 100 feet.  Move indoors and do not stay on roof, or move metal ladders, or touch anything made of metal when lightning is within 1 mile or can be heard or seen.
Why ground wire is needed
wire connector assortment Wire connectors are used to join wires
Make sure all copper is covered
Make sure wire nut cannot come off

Wire connector assortment at Amazon
How to select and install right wire nut
How to install a subpanel
Push on wire connectors Push on wire connectors
Push on wire connectors
Push on wire connectors at Amazon
Red 3P connector (shown) for 10-14 gauge wire
Electric safety when wiring timer
30 amp safety cut off
Safety switch
Fusable pull out
Fusable pull-out
Pull-out disconnect -or- Non-fusable Safety cut off 
for outdoor installation:
Locate cut-off next to electric equipment ... or short reach away... within sight of appliance.
Purpose to protect anyone working on electricity ... so person knows power is OFF, and power cannot accidently be turned ON.

How to wire safety switch

Residential information: varies by state and locale
Non-fusable safety switch required on outdoor installations, and high-voltage indoor applications such as 90 amp tankless electric water heater where breaker box not in plain sight of equipment.
Fusable vrs non-fusable: Non-fusable means there is no breaker or fuse inside the cut-off box. Non fusable is manually-operated on-off switch for safety.
Fusable means there is a fuse or breaker that trips when detecting high heat.

How to wire safety switch
Pullout Disconnect at Amazon
Fusable pullout disconnect
2-pole 30 amp fusable safety switch/ power cut-off
2-pole 60 amp non-fusable safety switch

Test for breaks in wire/ Test for voltage
Most appliance require 80% rated voltage to function correctly
Multimeters at Amazon
Electric testers at Amazon 
How to test and replace element
How to test thermocouple
Element tests for 120 volts
How to test wire
Safety when testing wires:
Never touch wet or previously flooded appliance.
Never stand on wet surface when working on electric.
Never stand on bare soil, put down dry boards.
Tape tester leads to wood sticks to keep hands away from power.
Use non-contact voltage tester before touching wires.
Never touch or lean into any made of metal.
Remove metal objects from pockets.
Do not use oxygen or fuel accelerants in same room as electrical repairs

Basic house wiring

Non-contact voltage tester
Test for power without touching connectors
NEVER assume power is OFF

Non-contact voltage tester Amazon
Electric testers at Amazon 
How to test electric power is off
wire connector assortment
Twist-on wire connector assortments
Do not reuse old connectors 

Connector assortment at Amazon
Connector assortment at Amazon

How to select and install twist-on wire connectors
Weatherproof wire connector
Weatherproof wire connector
Connector cavity is full of silicone
Built-in cover keeps silicone in place
Protect from water, dust etc
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Weatherproof size 14 to 6 Amazon
Weatherproof size 22 to 8 Amazon

How to select and install twist-on wire connectors
Wire connector wrench
Wrench to apply wire connectors
Tighten connector 

Wire connector blaster
Twist connector wrenches at Amazon

How to twist wire
How to select and install twist-on wire connectors

linesman pliers

Fire inside timer caused by stranded wire
Keep enclosure door closed at all times
soldering guns

Timer caught fire
Push on wire connectors
Push-on wire connectors in place of twist-on connectors
Push on wire connectors Amazon
Red 3P connector for 10-14 gauge wire
Lever connectors for stranded wire at Amazon
Terminal kit
Blue for 16-14 wire
Yellow for 12-10 wire
Read about terminals
How to install terminals
Lever switch
Weatherproof lever switch
Safely operate outdoor toggle switch
No need to lift cover
Replaces outdoor cover
Install over top of ordinary switch
Lever moves switch up-down
Works with single-pole, double-pole, 3PST, 3-way, 4-way switches etc
Use weatherproof box for outdoor
Can be used indoor or outdoor

Single-gang lever switch
Outdoor lever switches at Amazon

Gas and electric water heaters Buy:
Industrial electric at Amazon

Industrial supplies at Amazon

Industrial and scientific Amazon
Intermatic control centers Control centers:
+ manuals and parts

All control centers and parts

Including Z-wave
box timers Compare box timers

Control with Z-wave
programmable timer Compare programmable timers

Control water heater with programmable wall timer
Countdown timers Compare countdown timers

Control water heater with countdown timer

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