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How to wire Intermatic T103 and T104 timers

These instructions are for USA residential wiring only.

VERY IMPORTANT: Understand that in US residential wiring the WHITE wire is _NOT_ ALWAYS_ the neutral wire. Additionally, prior to 1999 the National Electric Code (NEC) did not require that these white wires be re-identified with black tape or similar means when used for purposes other than neutral. The white wire is sometimes used as a hot, especially when wiring Intermatic T103 and T104 timers.

Also understand that the WHITE neutral wire and the bare (or green) equipment grounding wire are connected together ONLY at the main electric power panel and must _never_be connected together _again_. Once those two wires leave the main electric panel, the WHITE neutral wire must _always_ remain insulated from the bare or green equipment grounding wire. This is very important for safety considerations.

If your wiring is very old and does not have a bare equipment grounding conductor, you _must_ protect the circuit with a GFCI (Ground Fault Circuit Interupter). GFCI wiring is not difficult but is beyond the scope of this post.

DETERMINE WHAT CABLE YOU HAVE:
Usually one will find one of the three following scenarios for the incoming supply cables when wiring a T103 or T104 Intermatic timer:

1...A 120 volt cable with 3 wires: black, white, and bare. The black is LINE (hot), white is neutral and bare is equipment grounding. Black to white is 120 volts. This scenario can be used with the T103, but not the T104.

2...A 240 volt cable with 3 wires: black, white, and bare. The black is LINE(hot), the WHITE is LINE (HOT), and the bare is equipment grounding. Black to white is 240 volts. This scenario is used with the T104 ONLY.

3...A 120/240 volt cable with 4 wires: Black, red, white, and bare. The black and red are (LINE) hot, white is neutral and bare is equipment grounding. Black to red is 240 volts. Black to white is 120 volts. Red to white is 120 volts. This scenario can be used with either the T103 or the T104.

The only difference between the T103 and the T104 is the timer motor voltage rating. The T103 uses a 120 volt timer motor and the T104 uses a 240 volt timer motor. The T103 timer motor is connected to terminal "A" and terminal #3 during manufacturing. The T104 timer motor is connected to terminal #1 and terminal 3# at the factory.

Also, when connecting the bare or green wires to the "GR" terminal, it is best to wirenut the wires together with a pigtail, then connect the pigtail to the "GR" (GRound) terminal, WHICH IS THE GREEN SCREW ON THE LOWER PART OF THE CASE.

WIRING THE TIMER:
The wiring diagram for the T103 is here:
http://www.progressive-growth.com/wiring/T103.pdf
___________________________________________________________________
WIRING THE T103 USING AN INCOMING 120/240 VOLT CABLE WITH 4 WIRES (scenario #3):

Incoming (LINE) wires from 240 volt circuit breaker:
Connect the black (LINE)(hot) wire to terminal #1. Connect the red (LINE) (hot) wire to terminal #3. Connect the white (neutral in this case) wire to terminal "A".
Connect the bare equipment grounding wire to the "GR" terminal, which is the green screw on the case.

Outgoing wires to 240 volt load:
Connect one (hot) wire to terminal #2 and the other (hot) wire to terminal #4. The bare or green wire goes to the "GR" terminal.
___________________________________________________________________
WIRING THE T103 USING AN INCOMING _120_ VOLT CABLE WITH 3 WIRES (scenario #1):

Incoming wires from 120 volt breaker or source:
Black (LINE) to terminal #3. White (neutral) to terminal "A". Bare to the "GR" terminal.

Terminals #1 and #2 are NOT used in this case.

Outgoing wires to 120 volt load(s):
Black(hot) to terminal #4. White(neutral) to terminal "A". Bare to the "GR" terminal.

The wiring diagram for the T104 is here:
http://www.progressive-growth.com/wiring/T104.pdf
______________________________________________________________
WIRING THE T104 USING AN INCOMING 240 VOLT CABLE WITH 3 WIRES (scenario #2):

Incoming (LINE) wires from breaker:
Connect the black (LINE) (hot) wire to terminal #1. Connect the white (LINE) (hot in this case) to terminal #3. Connect the bare wire to the "GR" terminal.

The "A" terminal is _NOT_ used.

Outgoing wires to load:
Connect one (hot) wire to terminal #2 and the other (hot) wire to terminal #4. Connect the bare or green wire to terminal "GR".

The "A" terminal is _NOT_ used.
______________________________________________________________
WIRING THE T104 USING AN INCOMING 240 VOLT CABLE WITH 4 WIRES:
Same as above, except the white wire is not used. Just tape or wirenut it off.

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1 Answer

I am replacing an on-off switch, with the 90610-wv dimmer. The instructions says there should be 2 black wires, and possibly a green. The wire in the existing switch has 1 white 1 black, and a bare copper wire. How do i connect these?


The important thing to remember is your switch has two wires.
Sometimes the colors vary a bit because of the specific circuit.
The green wire, when present, is a ground wire, and always connects to bare copper wire.

If your dimmer has two black wires, then connect dimmer-wires to either switch-wire
If the dimmer does not work, simply reverse the two wires.

If your dimmer has a red and black wire, then connect dimmer-black to switch-black, and dimmer-red to switch-white.
Again, if dimmer does not work, reverse the two wires.

Answer back if you have trouble, and I will help.

Oct 25, 2010 | Pass & Seymour Pass Seymour 90610WV 600W...

1 Answer

if you have 3 white and 3 black as well as a ground,how do you hook it up ?


If I understand correctly, your are replacing a GFCI receptacle with another GFCI receptacle

And your existing GFCI has 3 black and 3 white wires

And there is not a switch involved in the changeover.

I downloaded the manual from Lutron
http://classic.lutron.com/CMS400/techinfopage.aspx?id=22163

Every wiring diagram in manual shows:
Black wires connect to brass-colored screws
White wires connect to silver-colored screws

The brass and silver colored screws are typical of all residential receptacles. The color-code tells the electrician which terminal gets the black and white wires.

Are you having a problem putting 3 wires onto 2 screws?
It is a common problem.
You can buy a short piece of white and black wire at hardware store
Lets work on the black wires as example:
Strip back insulation on short piece of black wire
Hold together two of your black wires and start twisting them together
Now add the short wire to the two black wires you started twisting
Now twist together the two blacks and short black
So three wires are twisted together and you have a short lead that can connect to screw on GFCI
Put a wire nut over the twisted wire
Now you're ready to connect other end of short black wire to brass-colored screw
This reduces the number of wires that connect to screws

http://waterheatertimer.org/How-to-twist-electric-wire.html
http://waterheatertimer.org/How-to-select-right-wire-nut.html

Oct 20, 2010 | Lutron NTR-20-GFCI VAREO 20A GFCI...

1 Answer

My light kit wire is not connected


Blue, is usually international color for the NEUTRAL wire. EUROPE BROWN==PHASE BLUE===NEUTRAL Green/Yellow stripe==EARTH. (Most important wire)
USA. BLACK==PHASE WHITE==NEUTRAL GREEN/BARE==EARTH (Most important wire)

Mar 28, 2010 | Hampton Bay 24002 Ceiling Fan

2 Answers

Residential Electrical Wiring Current NEC


On a 120/240Volt single phase system is:

Black = 1st phase
Red = 2nd phase
White = neutral
Green or Bare = ground

3 phase is the same with the third phase being blue.

Jul 28, 2008 | Motorola 3-Wire Surveillance Headset...

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