Wiring a new light switch

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Hi all,
Sorry if this is really trivial, or has asked before, but I can't seem to find an answer.
I just bought a new light switch for the laundry room in the basement. It is a Leviton brand which has a bunch of buttons to give you a predefined amount of "on" time for the light - i.e. you hit the "10" button for 10 minutes of light.
The switch has 4 wires: Black, white, green, blue. The old basic switch has 2 wires - black and white. The wiring diagram from Leviton shows multiple wires coming in from the top and bottom of the switch box, and how to wire things appropriately.
My old switch has only the two wires: black and a white.
I assume the new switch green goes to the grounding screw on the box. I also assume the white should be joined to the white, and the black to the black, each through Marrs connectors.
What do I do with the blue. I've tried a couple of things (joining it in with the blacks) which powers the switch properly (it has LEDs that show which timer setting is in use) but the light doesn't go on - which is really the whole point of a switch....
What should I be doing?
TIA,
Dave
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snipped-for-privacy@rogers.com wrote:

I know exactly what you're talking about. Just put one of those in each of my bathrooms last year.

Short answer: you're screwed. Long answer: see below.

Yes, or to the bare wire that is (hopefully) present in the cable coming into the box.

Given your description (one black wire and one white wire connected to the switch) this assumption is almost certainly INcorrect. That's because the cable coming into your switch box is a switch leg, with no neutral conductor.
To wire this switch properly, you need to connect the black wire of the switch to a wire that's always hot, the blue wire to the light you want to control (I'm going from memory here -- I might have that backward -- check the instructions) and the white wire to neutral.
You don't have a neutral in that box.

Now wait a minute. "Blacks" *plural* ? A moment ago, it was a black and a white. No mention of anything else.
How many cables come into the switch box, and how many wires (and of what colors) are in each cable?

Depends on the answer to my question above: how many cables, and what's in them?
--
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Doug Miller (alphageek at milmac dot com)
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By blacks, I meant the one coming into the box, and the one that is part of the new switch. I optimistically, naively, (foolishly?) tried joining them together along w the blue. Got pretty LED lights on the switch, but nothing from the bulb.
So I've taken the advice given here and returned the thing for a far less pretty manual spring timer similar to the one in the link provided by Jeff Wisnia. After a small issue with the new unit not wanting to fit into the existing box (persuaded with hammer, my favourite tool) the whole thing works like a charm. And the wife somehow confuses my for someone who is handy around the house, but this and a few low voltage lights in the garden has been enough to earn a golfing pass for tomorrow morning.
A satisfactory outcome all round. Thanks!
Dave
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If you only have two wires, the black and the white in the switch box, that timer won't work. You need a mechanical timer. That timer requires a neutral. Your current switch has a hot wire and a return, but no neutral. If you had a neutral, you'd wire the hot to black, the neutral to white, and the load (wire that goes to the light), to blue

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You have to run another white wire to where the switch is from the light. Some light have the black, white and green(bare) ran up to the box the light is mounted to. The white wire goes to one side of the light socket. The bare wire goes to the grounding screw. From the switch you run a white and black wire toward the light. One of the wires (white) will go to the free black wire, the other (black ) will go to the light socket. What you need to do is get a wire from the white wire at the light socket to the new switches white wire. Then connect the black wire at teh switch to the black wire at the light socket box. Then run a wire form the blue wire of the new switch to the other side of the light socket.
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It sounds as if the switch itself needs power for the 'timer' function, hence the need for a white wire (common) to attach to the whites (commons) in the box These would not have been attached to the old switch, rather would have probably been joined with a wirenut in the back of the box. EXCEPT - since you say you have a white that is bare, that was probably connected to the old switch, I'm thinking your hot came into the light and what you have in your switch box is simply a drop down from the light. That is, you don't really have a common to connect to - that's only available in the box at the ceiling where it connects to the light.
Did you only have a black and a white connecting to the old switch? Did the white have any kind of marking on it (tape or paint) to indicate it was a hot and not a common?
My guess is that with your configuration you may not be able to use your new switch.

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snipped-for-privacy@rogers.com wrote:

As other posters indicted, you are probably screwed with that switch and your existing wiring. You _could_ always replace the 2-conductor romex between the switch and light with 3-conductor but that isn't trivial for a beginner and depending on how the walls and ceiling are finished can be a PITA for anyone.
How about this: take the timer switch back and try to get your money back. Then buy a "warm moving body detector" switch for about half the price. The common ones, such a Eagle that some big-box stores carry, can be wired to work in your situation. And they work even better in my experience than a timer since you don't have to touch anything -- you walk into the room and the light comes on and after you leave it waits for a pre-determined time and then switches off. Just the thing if you have your hands full. Best of all, the Eagle probably costs half of what your Leviton timer cost ($20 vs. $40?)
I've wired my garage bays and some entry switches with the Eagle brand units from the Borg and they work very well.
--
John McGaw
[Knoxville, TN, USA]
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Damn!
Given that many other posters gave the same opinion, I guess I'm toast unless I upgrade the wiring - and I'm not really keen on doing that....
So I will follow your suggestion and look for a motion detector switch. If that gets me some $$ refunded as well, then that would be a good thing too.
As an aside - my ISP recently ditched their news server, and so I've had to find another means to access usenet. I signed up to Google Groups a few months back, but have ended up just lurking in my favourite groups. Until now. So this was my first ever post from my new account, as well as a first ever to al.home.repair. I have to say I am mightily impressed with the speed, usefulness and general civility of the posts I've received. Better than I had any hopes for.
Thanks to all for your replies!
Dave
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The ones I have seen need a neutral for the same reason the timer does. Maybe some don't.
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Toller wrote:

Well, the Eagle Electric brand for sure does not need the neutral -- I've installed several and none of them had both hot and neutral in the switch box. Their drawing calls for the black to go to the hot and the red & brown to be nutted and connected to the load and the green to go the ground. Works fine every time for me. Who knows, they might be using the ground lead to provide the little bit of "neutral" current needed -- probably wouldn't meet code but I've not checked it out.
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John McGaw
[Knoxville, TN, USA]
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If they've got any brains at all, they're just trickling the working current down through the light, and it's just not enough to light it.
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Okay, why couldn't you do the same with the timer switch?
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No reason. Mind you, it may behave wierd with some loads that aren't necessarily (mostly) resistive.
Eg: trying to trickle a bit of juice thru a CF bulb might not work at all.
--
Chris Lewis, Una confibula non set est
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Damned if I know. My theory is that the people who built the timer switch weren't smart enough to think of it.
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Goedjn wrote:

Nah. Seems to me the "timers" working current has to be there when the light is ON, and that's when there should be NO voltage drop between those two wires to run the timer with. So you couldn't ask for a very large voltage drop there without having to put up with some significant power wastage and heating, depending on the size of the bulb load.
Now I suppose you could put a current transformer over the current carrying lead to the light bulbs and use the voltage developed on its secondary, after regulation, to run the timer circuit. But that's a long run for a short slide and transformers ain't cheap parts to make. Then again, they do use current transformers in all GFCIs, so maybe it's not such a whacky idea, and if a rustbucket like me could think of it, then other engineers could easily do the same.
Jeff
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In wrote:

The OP's switch may be different, but I have two electronic timer switches to turn lights on and off automatically at evening and morning. They are powered by trickle current wither the load is on or off. I think they just use such a small amount of power that it doesn't cause a significant voltage drop. I know they use current from the light ckt because if and only if all connected bulbs burn out, the timer loses its programming.
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Jim
"Remember, an amateur built the Ark; professionals built the Titanic."
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I have installed several motion-detector switches here, none of them need a neutral. They have 2 wires (or 3 if it has ground). I want one that uses a neutral.
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Mark Lloyd
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snipped-for-privacy@rogers.com wrote:

Dave - Don't despair - That switch sound pretty nice. You said this was a utility room, right? If so, can you see the wire from the switch to the light or does it run in a finished wall? Do you think you would be able to fish a different, or new, wire from your light to your switch? If you could get a different wire there then we could get that thing working for you.
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wrote:

I have one of those in my bathroom, which generally works well. It will not work properly wilt only compact fluorescent bulbs.

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Mark Lloyd
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snipped-for-privacy@rogers.com wrote:

You may not be able to use that switch as it requires a neutral connection in the box where the switch is... many times the neutral is at the fixture, and not at the switch at all.
The instructions are probably like this:
White - neutral Black - hot Blue - load Green - ground
Rob
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