Question about Intermatic T104M 208-277Volt 40-amp Timer Switch-Double Pole / Single Throw

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Installing of a t104 208-277 v

How to install this to a 30 30 amp breaker which is in the basement time is going to control 3 to 4 signs already powered by the breaker its self i just want to eliminate turning them off and on manually

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  • Joel Wiedeman May 11, 2010

    clock motor 208-277V rating?


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SOURCE: On 10/12/10 electrician installed an Intermatic

I believe your timer must be exposed to cold.
The CR2 battery in ST01C will only last 30 days when exposed to cold temperatures.
I was reading a pdf chart few months ago about timer batteries, and the power drop-off becomes really steep after 30 days.

Most digital programmable timers are susceptible to cold if they have battery or internal rechargeable battery that supports timer functions or acts as program back-up.
For example, I e-mailed Honeywell about their Aube rechargeable-battery-type-timer, and they said anything below 32F and the display becomes slow, and timer loses accuracy.

Your ST01C wiring is correct. I test timers. They don't operate if wiring is wrong.

I solved same problem with my back porch timer using GE 15070 mechanical dial timer. Home Depot sells in-store for $18.
Link below gives you photo, manual, and wiring instruction so you don't need electrician.
Open page and notice the timer below the 15070 has a photo insert showing on-off pins located on timer dial.
You move pins with ink pen or fingernail file.
Of course this is not self-adjusting digital timer, so I just set it for times I want, and it's easy to change times. It will be perfect for 6pm to 11pm daily.

And then use ST01C on a indoor switch.
You can wire the ST01C yourself by simply looking how each wire is connected now, or you can add a comment to this thread later and I will answer:

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Posted on Jan 11, 2011

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How can i connect a timer switch hager EH 010 to three phase DOL startor. the startor is using for 7.5 HP motor

Copy following links for installations:

EH 010 timer is rated 16 amp max.
Typically this timer is connected to 12-14 gauge wire
Typical 3-phase 7.5 Hp motor draws 22 amps at 230volt and probably connected to 30-40 amp breaker and size 10-6 wire.

Timer and wire to timer must be fuse-protected with 15a bus fuse or line fuse or fuse block, and cannot be directly connected to 30-40 amp line.

Add comment as needed.

Apr 18, 2013 | Timers

1 Answer

How can i connect a hager EH010 timer switch for DOL startor. the startor is using for 7.5 HP motor

Hello sajikumar

Following links have wiring illustrations:

The EH 010 timer has max amp rating 16 amp max.
This timer is connected to 12-14 gauge wire
Ordinary 3-phase 7.5 Hp motor draws 22 amps at 230volt and probably connected to 30-40 amp breaker and size 10-6 wire.

Timer and wire to timer must be fuse-protected, and cannot be directly connected to 30-40 amp line.

Add comment for more assistance.

Apr 18, 2013 | Timers

1 Answer

Can I install on a 20 amp circuit with a 15 amp GFCI plug? The unit says 120 v 6 amp max

Jan 2013
1) Yes. With 6 amps.
It is not purely code, but generally not dangerous.
Most household outlets and switches sold at home center are actually rated 15 amp, and should be on a 15 amp breaker. just don't overload.

2) However if you are running close-to or higher amps than 15 amps, such as space heater (volts x amps = watts), then I would suggest installing 20 amp arc-fault breaker, and protect whole circuit.

3) Add comment and say what you do.

Jan 22, 2013 | Malibu ML600TW - Low Voltage Power Pack -...

1 Answer

How to connect an omron h3y timer into a circuit

I see your comment to ignore:
To protect timer, read following:

1) Max load on this timer is 5 amp at 240volts

2) If load exceeds 5 amps, then use timer to control contactor.
Here is crude drawing showing basic wiring for pin timer controlling heavy amp load.

3) If amp rating on incoming wires exceeds 5 amp, for example is circuit breaker feeding circuit is 20-30 amps etc, then protect wires to timer using busman in-line fuseholder with fast-acting 5 amp cartridge fuse.

Dec 03, 2012 | Omron Healthcare Omron H3y-4 5 Second...

1 Answer

I have a wh21 Intermatic water heater timer. I installed the shut off and on switches. They are not working. I opened a manual and it stated to make sure the dial is pushed all the way in. I spun the dial...

You might have your Line and Load wires reversed.
Line wires come from circuit breaker.
Load wires go to water heater.

WH21 wiring: There are 2 Hot Line wires coming from breaker box that connect to terminals 1 and 2.
WH21 is SPST and turns off one Hot wire going to Load. So Load wires connect to terminals 2 and 3. Terminal 2 has 2 wires: 1 Line wire and 1 Load wire.

Keep in mind that WH21 is 25 amp, 2Hp 240Volt timer that will work on water heaters up to 4500 watts. Look at label on side of tank to see wattage. All appliances and motors have labels.

Larger wattage water heaters require 30 amp water heater timers as shown following page:

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For a price, expert works with you via e-mail while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

Feb 21, 2011 | Electric Intermatic Wh 21 Water Heater...

1 Answer


1) There is no speed adjustment on timer clock motors.
They are manufactured for 60 Hz, which is the controlling factor for motor speed.
60 is the number of cycles per second that AC electricity oscillates, caused by a turbine spinning inside magnetic field at power plant. This speed is very constant, and so clock motors keep correct time for years or decades.

2) A loose wire or loose circuit breaker could cause motor to lose power at times.
Clock would appear to run slow.
Check terminals. Make sure no insulation is sitting under the screw-down plate on timer terminals.
Tighten wires very tight against copper wire.
Move Hot wire to another circuit breaker and see if problem persists.
Tighten screw on neutral wire on neutral busbar inside breaker box.

3) Problem could also be bad clock motor for some reason.
For $16 replace T100 series 125Volt clock motor

4) Trippers contact a lever, make sure lever has bit of grease so trippers are not hanging on the lever. Off tripper moves lever one direction, ON tripper moves lever other direction.
Double check operation of lever by moving override back and forth.
Override should snap crisp and clean, and not be extraordinarily hard to move.


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Jan 05, 2011 | Intermatic T103 Indoor 120-Volt 40-amp...

1 Answer

Triing to install intermatic t103 please help. Source is 3 wire 110v want to run 3 blower 110v 9.5 amps each off the t103 timer. Don't have 220v in house just 110v. I need a very simple wiring diagram I...

T103 has 120Volt clock motor, so we can wire this timer.

T103 timer is rated for 30 amps and 2horsepower and your blowers use 28 amps.
So we're getting close to max on the timer. Hopefully blowers won't all be started at one time since motors draw maximum amperage when they start.
However, you need 30 amp breaker and orange 10 gauge wire for that much amperage >> unless only one blower is turned ON at any given time.
Always match wire size, amperage of breaker and amperage of Load or it will trip the breaker.
If you put 30 amp breaker on size 10 wire it is good. But 30 amp breaker on smaller size 14 or 12 gauge wire is fire hazard.
Add a comment at any time, and I will respond

Look at the basics:
You have 2 cables.
One cable comes from breaker box.
Other cable goes to three 120V plugs (120V is same as 110V).

Each cable has black-wire, white-wire and bare-copper-ground-wire.

How to wire the timer.
Timer has 5 terminals: A 1 2 3 4

A) Cable from breaker box:
White wire from breaker connects to terminal A
Black-wire from breaker connects to terminal 1

B) Cable going to 3 plugs
Black wire to plugs connects to terminal 2
White wire to plugs connects to terminal A
Ground wires connect to green ground screw.

Terminals 3 and 4 are not used in this case.
Here is a wiring diagram that shows 120Volt from breaker box and 120Volt going to Load

Nov 27, 2010 | Intermatic T103 Indoor 120-Volt 40-amp...

2 Answers

Install a timer to control pool operation

Another option would be to get an electronic timer like the Intermatic P1353 that has 3 circuits on it that you could program to cut on and off at different times. For example, you could have one circuit that controls the pump and turns the pump on, then the second circuit would turn on the booster pump at a set time after the filter pump had come on and then the heater could be set to also run at a preset time after the pump circuit was activated. Since the pump, booster and heater are all 220, it's a straight forward hookup with everything in one timer box.

The lights, as stated before, would be on a separate circuit (110) and have its own timer or photosensitive eye set in line.

May 05, 2010 | Intermatic & Indoor/Outdoor Rain Tight...

1 Answer

I need to instal a mechanical time switch

john, i'm assuming the water heater is 240 volts and the timer is 240 volts, if ok follow these instructions. the 2 wires coming from the breaker box goes on 1 & 3 screws, also each yellow wire going to the timer motor goes on 1 & 3. now the 2 wires going to the water heater goes on 2 & 4. be sure to ground the timer box

Apr 13, 2009 | Intermatic & Indoor/Outdoor Rain Tight...

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