I have a black and white wire to hook to. leviton has black, blue and white. green also but thats a ground. what do i do with the blue wire? this is a single switch to a gfci then to outside lighting. Replacing an Intermec SS7 timer that had blue, black wires only. blue was to white and black to black.

Connect the green dimmer wire to your ground wire

Open following link to identify timer:
http://waterheatertimer.org/Countdown-timer-horsepower-ratings.html#6230

Leviton 6200 series timer replaces single-pole switch. Will not work for 3-way or 4-way applications.
Timer has 4 wires: Blue, Black, White, Green
Timer Green to bare copper wire.
Timer Black to Hot wire from breaker.
Timer White to Neutral wire from breaker. Neutral wires are white wires that are twisted together and covered with wire nut pushed to back of box. If box does not have neutrals, connect Timer white to bare ground wire.
Timer Blue to Load wire.
If timer does not work, reverse Timer Black and Timer Blue.

This should replace any existing single pole (one location) switch. You have two wires on the pir, black and blue and then the ground. The black hooks to the hot or common wire. It may be black, but it will be the hot wire. The blue wire hooks to the wire going to the light. The ground hooks to the green or bare.

Leviton countdown timers have additional wire that powers internal electronics.
Leviton timers have red-black-white-green wires (or blue-black-white-green wires)

1) Regular single pole switch has 2 insulated wires. One of these wires is Hot from breaker, and the other goes to Load (fan)
2) Timer green wire connects to bare ground as you know.
3) Hot from breaker connects to timer black wire.
4) Load wire connects to timer red (or blue) wire.

5) Located in back of box are white wires that are twisted together and covered with wire nut.
These are Neutral wires. Connect timer white to these wires. This will power timer electronics.
6) If box does not have Neutral wires described above, then connect timer white to bare ground along with timer green wire.

7) Turn power ON and try timer countdown.
If timer does not work, then reverse timer red and timer black wire.

8) If box does not have neutral wires: Image on link below shows similar Intermatic timer:
Image applies ONLY when Neutral is not available.
http://waterheatertimer.org/images/EI210-wiring-full.jpg

Add a comment for more free help.
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You are replacing a single-pole switch that has two wires.

You posted under UPM timer.
But UPM timers have a red wire instead of a blue wire, so you have different brand.

Some GE programmable timers and some Leviton timers have a blue wire.
Here are instructions:
-Green wire goes to bare ground wire.

-Timer black wire goes to black wire
-Timer blue wire goes to white wire.

-Located in back of electric box are white wires twisted together and covered with wire nut. These are neutral wires. Timer white wire connects to these wires. This will power electronics inside the timer.
-If your box does not have white neutral wires described above, then connect timer white wire to bare ground wire along with timer green wire.
-Turn power ON, and push on-off button. If timer works, then it is wired correctly.
- If timer doesn't work, then reverse Timer blue and Timer black wires.
- If lights blink on-and-off, then you connected white wire incorrectly, review wiring shown above.

If your box does not have neutral wires or bare ground wire as described above, then buy Walmart.s Brinks 46-1022 or Intermatic ST01C or Intermatic EJ500 or Aube T1032. These timers do not need neutral or bare ground wire.

First thing to consider is size of Load.
Leviton countdown-timer Load rating is 1800 Watt, 120Volt.
Look inside Jacuzzi at rating plate on motor.
Rating plate on motor should give Volts, Watts and Amps.
Formula Volts x Amps = Watts.
Sometimes motor shows VA which is Watts
Is Jacuzzi on 240Volt breaker or 120V breaker?
Leviton countdown timer is not for 240V load.

A) If 120Volt electric Load checks out, here's how to wire timer if 1 cable enter box.
Timer-black-wire connects to jacuzzi-black
Timer-white-wire connects to ground.
Timer-green connects to ground.
Timer-red connects to jacuzzi-blue.

B) Here's how to wire timer if 2 cables enter box.
120Volt cable coming from breaker box has black, white and bare copper wire.
Timer-black-wire connects to black-wire-from-breaker
Timer-white-wire connects to white-wire-from-breaker-box.
Timer-green and jacuzzi-ground connect to ground

Timer-red-wire connects to jacuzzi-black-wire.

Jacuzzi-blue-wire connects to white.
I am puzzled why this wire is blue if circuit is 120Volt.

Switch has 2 black wires. One black is hot wire. One black is wire going to fan. Turn off power. Remove wires from switch and separate. Turn power back on. Using ordinary tester, test each black wire to bare copper ground wire. Only one of the black wires will test hot. The other black wire goes to fan.
Timer black wire connects to black hot
Timer blue wire connects to black wire going to fan
Timer white wire connects to white neutral (in absence of white neutral, connect Timer white wire to bare ground)
Timer green connects to bare ground wire

one of the white wires has power on it constantly....that wire connects to the black wire of the leviton.......the other white wire which has no power to it is going to whatever needs power so that wire connects to the red wire of the leviton....the green wire connects to the metal box where your mounting the leviton.

You need to have a pair of white wires wirenuted and shoved in the back of the box. White to white, black to the hot and blue to the load on the second black. Some of these have a yellow wire for three way connections.

You are correct in assuming green is the ground and connects to bare copper wire. Black is always the HOT wire and should be attached to the black wire. Red wire connects to white wire.