On-Off, Off-On, On-On, But NOT Off-Off


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Old 03-03-04, 09:26 PM
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Question On-Off, Off-On, On-On, But NOT Off-Off

This may sound strange, but...

I have a large basment room with three entrances. I have wired a circuit with 4-way switches to control the overhead lights. I have since decided that I would like to keep these switches at the entrances, but split the lights into two banks. That part's probably immaterial. Suffice it to say that I have a switched power feed to power both sets of lights. Is there some way to wire a single gang of control switches so that I can have at least one bank on ( or possibly two, but never zero).

So, in other words, when I walk in the room, and power on via the 4-way, it will turn on at least one set of lights, based on the control switches. By going to the control gang, I could switch to the other set, or turn on both, but not turn off both. This would ensure that whenever I enter the room and flip a 4-way, at least some light will turn on, no matter how the contol switches are set.

Hope that makes sense.

Thanks...
 
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Old 03-03-04, 09:47 PM
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4-way switches (plural)? When you want to control a light from three locations, you need two 3-way switches and one 4-way switch. I assume that this is what you have.

Actually, your posts did not make complete sense to me. Let me try to interpret:
  • Location one (the "control" location) has two switches. One switch can turn on or off bank "A". The other switch can turn on or off bank "B".
  • Location two has one switch. It can turn on or off bank "A".
  • Location three has one switch. It can turn on or off bank "B".
Will this do what you want? If so, then the solution is simple--it just involves two pairs of 3-way switches.
 
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Old 03-04-04, 04:37 AM
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I think that I understand what you want.

I read that you want to leave the existing switch wiring intact, but add some new switches so that one or both sets of lights have power.


I would do this as follows:

Take the hot wire feeding the lights from the last three way and use it to feed two three way switches in parallel.

Run one output from each switch to the first set of lights, and the second output from each switch to the other set of lights.

With this wiring you have four switch positions (both up, both down, up-down, and down-up). One of these positions will have light bank A hot. The opposite position will have light bank B hot. The last two positions will have both light banks hot.
 
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Old 03-04-04, 05:39 AM
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I think that Bob has the most practicable solution.

What you want is a 'selector switch', which in one form is essentially a single pole double throw switch with 'make before break' contacts. In one position power goes to circuit A, in the center position power goes to circuit A and B, and in the third position power goes to circuit B.

I did some quick checking, and didn't see one of these made for ordinary home wiring. I found some (low voltage, high current) battery selector switches, and I found some selector switches made for industrial controls. These are rated for the voltages and currents that would be used in lighting, but I don't know if their listing permits their use in home wiring.

http://web1.automationdirect.com/adc...r-Hammer_22mm_(E22_Series)/Selector_Switches/E22XBG1RR

The system that bob described will work like a selector switch, using easily available switches rated for home electrical wiring. You could even use a 'duplex' device, with two switches on a single yoke: http://doityourself.com/store/6088777.htm

-Jon
 
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Old 03-04-04, 08:03 PM
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Engineer Bob,

Yes, you understand what I'm trying to do. Would you mind taking a look at this graphic to see if I understand what you are suggesting to me.

Diagram

Thanks...
 
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Old 03-04-04, 09:27 PM
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That diagram looks exactly like what Bob recommended. It's pretty unusual, but it'll work.

It could also be done with one 3-way switch and one single-pole switch. The single pole switch would send power to both lights, and the 3-way would send power to one light or the other. With this setup, the single-pole switch could be turned on to force selection of both banks, and the 3-way selects one bank or the other whenever the single-pole switch is off.
 
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Old 03-05-04, 12:44 AM
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Your diagram is exactly what I proposed.
 
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Old 03-05-04, 09:56 AM
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One 3-way switch "selects" either "A but not B" or "B but not A". Simply "bridge" the 2 "Select" terminals of the 3-way switch with a single-pole switch which connects together the "A" & "B" switch-outputs.

Good Luck & Enjoy the Experience!!!!!!!!!!
 
 

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