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

Rolls of stranded wire

NMB is house wiring
UF is underground
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
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

Spools of ground wire
Ground rods 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.

Wire wire 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 houshold 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 houshold 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
Magnetec 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
Dayton Motors: Dayton Manufacturing is owned by WW Grainger. Contact Grainger.
Always connect ground wire.
" 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

Length of wire/ amp draw
Use larger wire and breaker with longer distance
3-phase wire size
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Single-phase/ 3-phase Wire and Breaker size chart

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Single-phase/ 3-phase Amp load by Kilowatt

Water heater wire size chart
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Water heater 
recommended Circuit Breaker size/ non-simultaneous
Residential water heaters are non-simultaneous. Tank label will show type of operation.
How electric water heaters work
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

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/ non-simultaneous
Residential water heaters are non-simultaneous
Same as chart above except showing actual amp draw instead of recommended breaker size

3 phase water heater
Simultaneous water heater wiring
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.pdf file
Water heater 
Amp draw/ simultaneous
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
in line fuse
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Use 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

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
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 usually 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
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
Additional links:
main breaker box
Larger image
See inside main breaker box
Electricity leaves power plant What is 3-phase electric: power plant to end user
How to wire 3-phase timer
3-phase water heater

Basic household wiring
Basic water heater circuit

Figure volts amps watts for electric water heater
Test elements
Replace elements
How to wire tankless electric
How to change water heater temperature using timer
Change water heater from 240Volt to 120Volt
Replace thermostats
How to wire thermostats
How to wire water heater for off peak operation

How to twist wire
How to wire Cooper 277 pilot light switch
How to wire combo switch-outlet
How to replace 3-speed fan switch 

How to wire dimmer
How to wire 3-way dimmer
How to wire occupancy switch
How to wire motion detector
How to wire TM811 and TM8111 switches
How to wire wall timers
How to wire box timers
How to wire off-delay timer
Wire off-delay timer
How to wire pin timers

How to wire and troubleshoot photo eyes
Reverse photoeye so it turns on in day
24 Volt photoeye
24 volt programmable timer

How to wire switches
How to add switch
How to add 3-way switch

Timer for 3-way switch
Timer for 4-way switch
How to add outlet 
How to wire 3-way switches
How to wire 4-way switches

Troubleshoot Malibu outdoor lights
Select and install wire connectors
Select wire size

Electrical formulas
Electricians forum 
Electrical pages

How to wire arc fault breaker
How to wire GFCI
How to wire GFCI combo

Basic water heater circuit
How to wire water heater for 120Volt
Install old work box

How to drop wire from attic
Wire connector

How to wire 240volt outlets
How to install 3-phase timer
How to wire 3-phase outlets
How to wire 3-phase surge protector
What is 3-phase

How to wire whole house surge protector
How to wire under-counter water heater 

See inside main breaker box
Replace breaker
Install subpanel
How to solder wires
Whole house surge protector
3-phase surge protection
Circuit breakers

Difference between 120 volt and 240 Volt
Difference between 50Hz and 60Hz
How to install electric meter on water heater
How to wire water heater thermostat
How to wire water heater with switches and timers

6x6x4 Enclosures
Intermatic timer enclosures

Convert AC water heater to DC
How to wire DC solar water heater
DC relays for solar water heater
How to add another thermostat to water heater

How many Kwh to heat water
Chart for figuring heating time for electric heater
Gas and electric water heaters Industrial electric at Amazon

Industrial supplies at Amazon

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

All control centers:
+ manuals and parts

Including Z-wave
box timers Compare box timers

Compare ways to control Gas and Electric heaters
programmable timer Compare programmable timers

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

Control water heater with countdown timer
Compare power packs

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