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Packard contactor

2-pole 40 amp contactor

With removeable dust cover on top.
Select voltage needed to control coil.
Buy 2-Pole 40A resistive
120Volt coil At Amazon
240Volt coil At Amazon
24 volt coil at Amazon
Mars 2-pole and 3-pole contactors at Amazon

Fasco info sheet
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What is a contactor?

Contactor is a switch. It is rated for high amp loads.
High amp causes heat. Heat will damage regular electrical parts.
Timers and wall switches can be damaged by high amperage.
Each switch and timer has amp rating.
Contactors are rated for more amps than ordinary wall switch or timer.

The electrical circuit lasts longer when a contactor is used because contact points on a contactor are designed to switch high amp loads without melting or being damaged by heat.
The electromagnetic coil can be switched on-off using ordinary wall switch or timer.
When voltage is applied to coil, then contact points close, and heavy amp circuit turns on.
This lets you control heavy amp loads using ordinary wall switch or timer.
45EG20AF in box
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2-pole 40 amp contactor in 6x6x4 enclosure

Using #8-32 x 3/4" bolts
Install contactor at angle leaves room for wire

This is DPST contactor
Double pole, single throw.
So the contactor is 2-pole. It can turn off 2 wires.
And single throw because both poles are on-off at same time.
So you can switch both wires in 240 volt circuit.

How to wire contactor for water heater

Specifications for 2 pole contactor

Each contactor has amp rating: this is the number of amps that can be safely handled by the the contacto points
Each contactor has coil voltage rating: this is the voltage needed to operate the switching coil
Approx 1-3/4" wide  x 3-1/2" long x 3" tall
Coil burden or coil VA is 7.3 Watts, inrush is 27 Watts.
Life expectancy <> 0.5 - 2.0 million operations
Life expectancy of Siemens definite purpose controllers
Contactor dimensions
single-pole contactor
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1-pole contactor

Only leg is turned on-off, while other leg is continuously connected

Single pole contactors at Amazon
3 phase contactor

3-pole contactor for loads up to 90 amp

For loads up to 90 amp
For coil voltages: 24, 120, 208-240, 277, 480 volt
Control 3-phase with contactor

3-pole contactors

What is 3-phase
How to wire 3-phase timers and contactors
How to convert 3-phase water heater to single phase

30 amp, 2-pole, open frame power relay with enclosure

SPDT.... dfifferent from DPST shown above.
Both perform same job. Both have 2 sets contacts. SPDT has extra set contacts so a second load can be turned on-off exactly opposite from off-on other load.

Buy from my affiliate links
Magnecraft box and cover
magnecraft w199 relays at Amazon
Siemens power relays at Amazon

Difference between relay and contactor
DC relays for solar panels
Mount open frame relay on din rail/ .jpg
Smarthings Hub
CA3750 can be set to operate as one switch or two switches

30 amp, Z-wave contactor with enclosure

Selectable voltage: 120, 208, 240, 277 volt
Opertate DPST or 2 x SPST contactor with z-wave
Two sets of contacts can be operated at same time, or separately.
So you can control different voltages at same time.

Intermatic CA3750 at Amazon
Smarthings Hub at Amazon
Contactor controlled by remote Z wave

How to wire and set up CA3750

Wires connect to contactor using female terminals

Hot and neutral can connect to either side.

120Volt coil At Amazon
240Volt coil At Amazon

Mars 2-pole and 3-pole contactors at Amazon

Furnas cross reference
Siemens cross reference
3-pole contactors


Terminal kit at Amazon with crimp tool
Electrical terminals at Amazon
Blue 14-16 gauge female terminals 20 pcs at Amazon
Yellow 12-10 gauge female terminal 16 pcs
360 pc assortment at Amazon
520 pc assortment at Amazon
More about #10 & 14 female terminals

PB 300 connected to water heater
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Connect modular timer to contactor

PB series and other timer modules
24 volt programmable timers

Sprinkler timer connects to contactor

Convert 24 volt sprinkler timer to 120 volt Resource:
How to wire Intermatic sprinkler timers

3-pole contactor

Control 3-phase using contactor

3-phase contactors

How to wire 3-phase timer
How to wire 3-phase
What is 3-phase
Compare 40 amp box timers
Compare all box timers
Override T104 timer

Override T104 timer

T104 timer wiring
T100 series timers
Compare all box timers
Pool control centers
Freeze controls
Control motor with 2 switches
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Control motor with 2 switches

Same wiring diagram applies to single-pole switch

Buy Contactor with 240Volt coil

240Volt coil At Amazon

Start winding pulls more amps than switch can safely handle.
Over time, the switch will fail.
Contactors are rated for heavy amp loads, with expected life of millions of operations

Delay timer for motor or pump
Control motor with 2 switches or timer
Motor troubleshoot and resources

Omron LY23 AC Model terminals/ back to front:
7-8 magnet terminals (turned opposite direction from other pins)
5-6 common terminals
3-4 NO normally open terminals (power is off when relay off)
1-2 NC normally closed terminals (power is On when relay is off)
Load rating 7.5 amps AC
900 watts incandescent @ 120V
1800 watts incandescent @ 240V
1/4 Hp motor @ 120V; 1/2 Hp @ 240V
To reverse operation of photo-eye
So Load comes on during daylight hours
photo eye connected to DPDT relay

30 Amp relay x 80% = 24 amp max up to 2880 watt @ 120V or 5600 watt @ 240V
30 amp 10 gauge wire up to 2 Hp @ 50' or 1.5 Hp @ 100' @ 120V See load charts
Use Omron 120volt LY2-AC 8-pin relay for 7.5 amp.
    NO NC Relay
    7.5Amp Omron         30Amp DPDT
Omron LY2 at Amazon / Choose 120Volt coil
30 Amp relay at Amazon
12amp DPDT Packard at Amazon
Omron relay/Page 450 / pdf
Reverse Motion detector

Reverse motion sensor so Load turns OFF

Motion sensor
Motion sensor at Amazon

How to wire motion sensor

Heavy-duty relay

Optional box and cover for magnecraft

Recommend this relay for motors exceeding 120 volt 1 HP/ 240 volt 2 HP
Magnecraft relay with NO NC terminals 120 volt coil or 24 volt coil
Buy from my affiliate links
Magnecraft box and cover
magnecraft w199 relays at Amazon
Siemens power relays at Amazon

How to reverse motor with switch
Difference between contactor and relay
Relays for DC motors and solar panels
Control motor with 2 switches
Start two motors at different times
Solid state relay

Solid state relay/ SPST

Check for AC-AC input-output

DC input to AC output is most common

AC to AC input 80-280V AC input 24-380V AC
AC to AC output 24V to 480V input  80 to 250V
Solid state with heat sink
Solid State relays at Amazon
Solid state relay at Amazon
100-240Volt AC input / 20 amp/ at Amazon
80-250Volt AC input/ AC output/ 40 amp/ at Amazon

Electromechanical relay vrs solid state relay/ pdf

DC to DC solid state relays

Buy from my associate links
100 volt 25 amp DC Relay
200 volt 25 amp DC relay at Amazon
Relay safety cover
Heat sink

Read how to convert AC water heater to DC/ high voltage
Convert AC water heater to DC/ low voltage
Electromechanical relay vrs solid state relay/ pdf
SPDT model C shown/ 30 amp NO terminal/ 20 amp NC @ 277 V
Also avaiable SPST model A/ 30 amp NO terminal @ 277 V
Base 1.08" x 1.98" / 1.09" high

Zettler 30 amp miniature power relay

Coil voltage 120-240 VAC / also DC ratings
Contact ratings 277 volt AC/ 28 VDC
Use quick connect terminals


Atwood minature relay
120Volt SPST minature relay at Amazon
240 Volt at Amazon
Zettler relays at Amazon

Zettler relay wiring
Overide thermostat with programmable timer
Manual/ spec sheet
 DC power relay
250VDC    25 amp                                                                     400VDC  200 amp               

DC to DC relay/ mechanical type

DC power relays

Full on-off contacts/ 12 or 24 volt DC coil
250 volt / 25 amp DC load
250V x 25 amp = 6250 watt
Connect 12 or 24 volt DC to terminals 3-4;
Connect load to terminals 1-2

Electromechanical DC-DC G9EB-1 relay
24 VDC coil and 400 VDC/ 200 amp contacts
Omron relay at online

DC relays for solar power
Omron DC-DC pdf
DC power relay spec sheet
12 Volt DC relay
Coil 12-24 VDC
Load contacts 26 VDC  40-50 Amp

12 VDC 40-50 amp DC power relay

W199AX-3 relay
W199PX-13/ 50 amp at 26 VDC = 1400 watt
X199 Magnecraft relay
Magnecraft W199 DC relay

Magnecraft relay / pdf
enclosed relay

Enclosed relays/ Functional devices

Enclosed relays at Amazon
3PST AC-DC at Amazon
Functional relays at Amazon

Aprilaire relay

Amp relay

When amp exceeds amp set point, the relay activates 120 volt circuit.
Recirculation pump is 1/25 Hp or 30 watts divided by 120 volts = .25 amp\
1 Hp motor is 750 watts divided by 120 volts = 6.25 amp
Use relay to control contactor when load exceeds 50 watts
Use to activate duct booster fan
Take off bracket and install bracket around a control wire that carries amperage
When amperage flows across line, the Aprilaire relay activates... and closes circuit going to 120 Volt load... such as indicator light... or another relay etc... the indicator light turns ON.
Wrap the wire multiple times to increase measurable current
Use a current transformer to reduce current

Aprilaire relay 4 amp at Amazon
Suncourt relay 1.2- 40 amp at Amazon
NK technology .75 amp at Amazon
NK technology sensing switch
Louensy 0-200 amp
johnson current sensing
Low amp current indicator
Current sensing relays
Current sensing switch
Current Transformer
Current sensor module

Aprilaire manual .pdf
Johnson control amp sensing switch/ pdf
NK tecknology AC current sensing switch/ pdf
Contactor maintenance
Life expectancy <> 0.5 - 2.0 million operations

Contact points stick sometimes

Solution: use nail file or emery board or folded sandpaper to clean off points.

Handy trick
Add indicator light so you can see when water heater is on. If points stick, indicator light remains on.

Electrical formulas
Indicator light
240Volt Pilot light at Amazon
How to wire water heater pilot light

Add to water heater indicator light page:
Low amp current indicator
Additional links
Electricity leaves power plant What is 3-phase electric: power plant to end user

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 Resources:
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
Gas and electric water heaters Industrial electric at Amazon

Industrial supplies at Amazon

Industrial and scientific Amazon
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box timers Compare box timers

Control water heater w/ Z-wave
Intermatic control centers Control centers:
+ manuals and parts

All control centers and parts

Including 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
Low voltage power packs Low voltage transformers

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