# purpose of jumper wire w/ 3 way light timer?



## 68 Malibu 383 (Apr 3, 2010)

If you have a light timer in place of one switch on 3 way switch, instructions show a jumper between the common and another terminal on the switch. Instructions for this switch show that (sorry, I can't copy/paste the diagram.) http://www.smarthome.com/20464/UPM-ETW193-Programmable-Wall-Switch-Timer-500W/p.aspx

The jumper makes the black wire leaving that box hot regardless of the position of the switch. The black wire leaving the box containing the Hot Switch might as well just be connected to the Common terminal.

So, what is the purpose of the jumper wire?


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## Speedy Petey (Jan 10, 2007)

It's only a direct wire if the timer switch lets it. 
Look at the diagram again, you'll see it.


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## 480sparky (Sep 20, 2007)

The 3-way that's paired with the timer just needs to 'signal' the timer that it's been switched from one position to the other.

If the timer had been getting power from the red, then it changes to the black, then it 'knows' you have toggled the other three way, causing it to either turn the light on or off, depending on it's state before you touched the switch.


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## 68 Malibu 383 (Apr 3, 2010)

Well, just replaced the timer and it works but the load switch does nothing. Should I not be able to turn the lights on and off with the load switch regardless of what the timer is doing (timer is in place of the hot switch)?

Whomever installed this originally had the jumper between the common wire and the red wire on the load switch and I moved the jumper as it is supposed to be per the instructions.


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## Dennis Alwon (May 9, 2009)

The purpose of the jumper is to keep power at the timer at all times when the switch is in the load side 3 way. On the line side three way it is making sure the load to the light is always at the timer.

If the timer is activated by time you cannot turn the light off from the remote switch. At least that is what it looks like to me. However if the switches are used manually then it will work as a normal 3 way if the timer is not activated.


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## 68 Malibu 383 (Apr 3, 2010)

Thanks.

I think I need to swap the red wire and black going to the light on this load switch. See attached.


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## Dennis Alwon (May 9, 2009)

68 Malibu 383 said:


> Thanks.
> 
> I think I need to swap the red wire and black going to the light on this load switch.


Going from memory I think that is correct.


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