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Color-code for residential wire/ how to match wire size and circuit breaker
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 /

10-2 gauge/ 30 amp
10-3/ 30 amp
Southwire electric tools
Yellow 12 gauge 20 amp

Yellow/ #12 gauge wire for 20 amp
with ground
12-2 gauge/ 20 amp
12-3/ 20 amp

NMB is house wiring
UF is underground
Rolls of stranded wire
White 14 gauge 15 amp

White/ #14 gauge wire for 15 amp
with ground
14-2 gauge/ 15 amp
14-3/ 15 amp

NMB is house wiring
UF is underground
armored cable
Armored cable
Southwire armored cable cutter
Southwire armored cable cutter
Rolls of stranded wire

Stranded wire
stranded wire
Rolls of stranded wire
50-60 amp breaker use 6 gauge /
6-2 wire
6-2 wire
Southwire electric tools
NMB is house wiring
UF is underground
40-50 amp breaker use 8 gauge /
6-2 wire
8-2 wire
Southwire electric tools
NMB is house wiring
UF is underground
Copper ground wire
Use same size as other wire in circuit

12 gauge copper ground wire
Ground wire
Green ground wire
Ground pigtails
Ground rods/ ground clamps at Amazon

Household NM-B Wires are color-coded so inspectors/ electricians can easily identify which wire is used during construction
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 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. More information below.
Main breaker terminals are still Hot when main breaker is turned off.

Southwire at Amazon
How to replace circuit breaker
Match breaker to voltage that shows on appliance label
3-phase breakers are used for commercial service panels

How to replace circuit breaker
3-phase wiring
wire size chart 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.
Aluminum wire expands when electricity travels through wire. Expansion causes loose connections and fire hazard.
Rating for short lengths household NM-B and DU-F
Larger image with wire types, temperature, long length
Maximum wattage for household NM-B and DU-F wires
Wire diameter, weight, resistance

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How to figure correct size wire and breaker
Use chart on left to select wire and breaker (for short lengths of wire)
Use the 80% rule when calculating Capacity.
wattage shown on chart shows the 80% rule.
When wires and breakers operate at 100%, they get warm.
Warm wires mean amp loss and potential fire hazard.
Warm breaker means that breaker will not last as long, and busbar can be damaged by heat (over period of time)

14 ga wire ++  rated for 120 Volts x 15 Amp = 1800 Watts x 80% = 1440 Watts safe maximum

12 ga wire ++ rated for 120 Volts x 20 Amps = 2400 Watts x 80% = 1920 Watts safe maximum

10 ga wire ++ rated for 240 Volts x 30 Amps = 7200 Watts x 80% = 5760 Watts safe maximum

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Longer distance requires larger breaker and larger wire
Look at label to find watt rating of appliance, or motor or tool
measure distance between appliance and main breaker panel
Use chart to select larger wire when needed
Volts x amps = watts
Watts divided by volts = amps
Volts squared divided by watts = ohms

Electrical formulas

Larger image with wire types, temperature, long length
Maximum wattage for household NM-B and DU-F wires
Wire diameter, weight, resistance

circuit breaker resources
Circuit breaker resources
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/ use tandem
Circuit breakers
How to install subpanel
Why you need ground wire
See inside breaker box
How to wire safety switch
How to wire whole house surge protector
Figure volts amps and watts
Figure correct wire and breaker
Types of surge protection
amp draw for motor
Volts x Amps = Watts
Amps = Watts divided by Volts

Typical motor starting currents of 6 to 8 times normal running current when starting.
Motor amp draw

AO smith / Century / motors at Amazon
Dayton motors at Amazon
Electric motors at Amazon
Draft inducer blowers for gas appliance + water heater
Water pumps at Amazon
Wet dry vacs

Motors can run 10% more or 10% less than rated voltage
AO Smith motors with troubleshoot and wiring .pdf
AO Smith motor wiring
Magnetic motors is AO Smith, AO Smith motors are now Century
Motor troubleshooting/ pdf
Motor troubleshoot 2/ pdf
Timer for 2-speed motor
Repair and wire motors .pdf
Basic motor wiring illustration .jpg
Reverse motor .pdf
Hayward pool equipment error codes
Swimming pool replacement motors and identification
The motor doctor
Dayton motor guide/ pdf
Control motor with 2 switches
Wattage consumption of motor .pdf
Always connect ground wire.

Timers intended for use with motors include the following ratings:
FLA:           Full-Load Amperes
LRA:           Locked rotor amperage
Calculate inrush for 3-phase motor:
Inrush is the amp consumption of a motor during start-up.
Motors are inductive and inductive loads consume more amps when starting. Once the motor has started, the amperage drops to normal.
Residential single-phase motors also have inrush, but this is generally not an issue since the start is brief, and circuit breaker doesn't react fast enough to trip with the brief surge of amperage (heat) on the wire.

Each motor has a label with a locked-rotor code that is needed for the calculation.
The locked rotor code is a letter A-V, with each letter corresponding to a range of KVA per HP (horsepower).
KVA is kilo volt amps. Volt amps is watts. So KVA is a measure of watts or power ... how much power the motor delivers.
The locked rotor code is used to calculate the inrush or amperage needed for that specific motor during start up.

The example problem on left shows motor with locked-rotor H, which has KVA range of 6.3-7.1 KVA per HP.
The KVA range is plugged into the formula:
P (power) = E (volts) x I (amperage) x .173
1.73 is the square root of 3, used for 3-phase calculations.

Locked rotor KVA nameplate rating: Calculate inrush .pdf
Difference between single-phase and 3-phase

" Current capacity must be adequate enough to maintain rated voltage at the motor terminals under all conditions. If it’s too high, contact the local utility.
If it’s too low check for overloaded circuits, loose connections or wire of the wrong gauge"
More than 3300 feet above sea level, use next higher horsepower.
Motor must be grounded. Test that ground is connected. Turn power off before touching motor.
Incorrect voltage at motor will cause motor to overheat. Check wire size.
Motors are hot to touch. Provide ample circulation around motor.
Horsepower / wire size / distance
Motor horsepower and wire size for 115Volt and 240V
Horsepower = watts 746
How to wire subpanel

For example: 1-1⁄2 Hp motor at 115 volts over a distance of 150 feet, use #8 wire.
If the motor can be installed to operate on 230 volts, #12 wire should be sufficient for a 150 foot distance

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Horsepower / wire size / distance
Use larger wire and breaker with longer distance
Length of wire/ amp draw chart

3-phase wire size
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Single-phase/ 3-phase Wire and Breaker size chart

What is 3-phase
How to wire 3-phase
3-phase timer
3-phase contactor
Difference between single-phase and 3-phase

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Single-phase/ 3-phase Amp load by Kilowatt
Water heater wire size chart
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Water heater Circuit Breaker size/

Ordinary residential water heaters are non-simultaneous. Tank label will show type of operation.
Longer distance, use larger wire and breaker
Oversizing wire and breaker will lower heat loss and improve efficiency
Cooler wires = cooler circuit breaker = longer life for breakers and main panel
How electric water heaters work

Dual-element water heaters are 240Volt and are normally factory-wired for non-simultaneous.
This means only one element is ON at a time.
Both elements are never ON at same time.
How to wire water heater elements and thermostats
How to wire tankless electric water heater
Single-phase water heater amp draw
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Water heater  Amp draw/

Ordinary residential water heaters are non-simultaneous
Same as chart above except showing actual amp draw instead of recommended breaker size
Simultaneous water heater wiring
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.pdf file
Water heater  Amp draw/

Residential water heater, or commercial water heater can be wired for simultaneous operation.
Some regions require commercial food sellers to have manufacturer-certified commercial-grade simultaneous water heater
Simultaneous is NOT typical for ordinary residential water heaters, except special order, or some models with 80 gallon capacity. Tank label will show type of operation.
Chart shows typical residential single-phase 120Volt, and 240Volt.
Chart also shows voltages found with commercial 3-phase service.
Water heaters can be wired for 3-phase
How to wire water heater for simultaneous operation
How to wire 3-phase water heater
30 amp switches 30 amp double-pole 30 amp DPDT Ordinary 15-20 amp switches 15 amp pilot light
Cooper 30 Amp switch
Single-pole/ 2-pole on-off switches
30 amp 2-pole switch
30 amp industrial grade

Heavy duty double-pole switches to turn off both hot wires in 240 volt circuit
30 amp motor switch
40 amp motor switch
Double pole double throw 30 amp switch
30 amp DPDT switch

Use this switch to toggle water heater between 120-240 volt
single-pole switch
Ordinary 15-20 amp toggle switch
15 amp switch
20 amp switch

Indicator light shows when Load is ON
Pilot light switch
How to wire pilot light switch
water heater circuit breaker

4500 watt and 5500 watt water heaters should connect to 30 amp breaker and 10 gauge wire.
Calculate safe maximum for water heater circuit
If residential water heater is connected to 20 amp breaker and 12 gauge wire, then overheating problem occurs over time.
Circuit breaker will not last as long, and damage can occur to busbar.
See basic water heater circuit
How to replace circuit breaker
20 amp breaker is subject to 80% safe-maximum rule.
20 amp circuit breaker x .8 = 16 amps. So safe maximum for 20 amp breaker is 16 amps.
240Volt 4500 watt water heater draws 18.75 amps. And 5500 watt water heater draws 22.91 amps.
So 20 amp breaker with 12 gauge wire is rated too small for most water heaters. Over time the breaker is getting warm, and is more likely to get hot and fail.

Recommended that all water heaters be connected to 30 amp breaker and 10 gauge wire.
Safe maximum for 30 amp breaker x .8 = 24 amps.
Safe maximum for 10 gauge wire at 240volts is 5670 watts See chart
30 amp breaker and 10 gauge wire run cooler, with less heat loss and more efficiency. Circuit breaker and main box last longer with less chance for heat damage.
Figure Volts Amps Watts for water heater
in line fuse
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In-line fuse.... When connecting 2 different gauge wires
Connect 12 gauge wire to 10 gauge wire.
Illustration shows smaller 12 gauge wire connected to larger 10 gauge wire.

10 gauge wire is protected by 30 amp breaker
The amp draw on 30 amp breaker is too large for 12 gauge wire.
12 gauge wire should have 20 amp breaker.

Use busman fuseholder with 20 amp fuse.
Fuse will protect entire length of 12 gauge wire.
Connect fuse to Hot wire.
Not necessary to put fuse on Neutral

If the 12 gauge wire was wired for 240V, then fuse is necessary for both hot wires.
Always make connections inside a box with cover
Buy fuseholder at Amazon
Buy fuseholders at Amazon
See fuseholder
GFCI in breaker box Household Main panel 120 volt and 240 volt
This is called single-phase electric power. Phasing is determined by the power company.

- Each 120 volt circuit can include up to 12 outlets, and supply power to lights inside a room.
- Generally each 120 volt circuit sends power to one area of home. This is because the wire leaves breaker box and goes to first junction box inside a room. From the junction box, the wire splits off and goes to each individual box, jumping from box to box until the final box is reached. So each box will have 1 black hot wire, 1 white neutral wire, and 1 ground wire that connect back to main breaker box.
- Some circuit breakers are dedicated to 1 specific appliance. For example the kitchen microwave is usually wired to 1 circuit breaker and no other outlets or lights are connected to that breaker. This is because microwave draws so much amperage. That is called dedicated circuit, and dedicated breaker.

- Each 240 volt circuit is dedicated to one appliance. For example electric water heater is connected to 1 240 volt breaker. The electric dryer is connected to another 240 volt breaker. The heat/AC is connected to another 240 volt circuit breaker, and so on.
See inside main breaker box
Basic house wiring
How to replace circuit breaker
How to install subpanel
Figure volts amps watts for electric water heater
How to wire GFCI
How to wire Arc fault breaker

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
Buy from my affiliate links
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
When removing insulation from wire, do NOT score or put cuts on surface of copper wire. Doing so increases resistances on wire and creates weak point.
Buy tools:
Wire strippers at Amazon
Linesman pliers
Utility knife at Amazon
End cutting nippers at Amazon

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

Insulation resistance tester:
Is the wire insulation still good?
Test insulation of wire
Power is off/
Test wire to sheath of wire insulation
Temperature and humidity measurements affect outcome

Insulation resistance tester
How to test wire insulation
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
Electricity leaves power plant What is 3-phase electric: power plant to end user
Basic house wiring
How to wire 3-phase timer
Support the economy:
Buy water heaters from my associate links:

50 gallon Gas water heaters at Amazon
40 gallon gas water heaters at Amazon
50 gallon Electric water heaters at Amazon
40 gallon electric water heaters at Amazon
Hybrid / heat pump/ water heaters at Amazon

How to install gas water heater
How to install electric water heater
Troubleshoot gas water heater
Troubleshoot electric water heater
Point of use water heaters
Troubleshoot Gas valves with manuals
Icon gas valve

How to replace water heater element Waste King disposal
How to wire tankless electric

Install point of use water heater
Titan tankless

Contactors/ relays
Install and troubleshoot garbage disposal Waste King disposal
Programmable timers

Woods timers
surge protection
Anode rods anode rods
Recirculation system

Tankless recirculation
Point of use water heater
Type 1 and type 2 surge protection surge protection
Gas and electric water heaters Buy
Industrial electric

Industrial supplies

Tools and home improvement

Home and garden

Hayward pool
Pentair pool

Southwire electric

Black and Decker

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

Campbell Hausfeld air powered
Tekton automotive

Powerbuilt automotive
Saws and saw blades
box timers Resource:
Compare box timers
DPDT timers
Control water heater w/ Z-wave
Intermatic control centers Resource:
Intermatic control centers: and parts
Digital control centers and parts
Tork control centers and parts
All control centers and parts
programmable timer Resource:
Programmable timers
Countdown timers
Off delay timers
On delay timers
Timer modules
Din rail
Twin & one-shot
Low voltage power packs Recirculation systems
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