wall switch that acts like a three-way lamp switch

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RustyShackleford

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electrical engineer
Customer wants to use rope lights along the top of a valance, LED ones that aren't dimmable. His clever idea is to use a split duplex outlet to power the rope lights: three strands of rope, 2 connected to one outlet and a third to the other. By turning on one, or the other, or both outlets, three different light levels: just like a three-way table lamp that uses a bulb with one 50-watt element and one 100-watt element. Seems like a lot of trouble, but not really; one rope strand is not bright enough anyhow, and running the split outlets just requires using 14-3 instead of 14-2.

But the switch ... It's easy to find a rotary switch that does the job:

http://www.hubbellcatalog.com/raco/raco_datasheet.asp?PN=6357&FAM=RacoSpecialtySwitche

... but not one designed as a single gang wall switch. I wonder if anyone knows of such a thing ? Or sees an NEC or other problem just mounting the above in a switch plate (since there'd be no yoke connecting the switch to the box) ?
 
K8MHZ said:
Two would work.

One controls one string, the other controls the other two.

First switch on only, one string, first switch off, second on, two strings, both switches on, all three strings lit. And both off would, of course, be all off.
Click to expand...

Good thinking
 
Thanks guys.

That Carson switch (the 3A254) is close, but the HI setting would have to energize the red & blue wires - no way to do that without some logic or relays or something.

Yes, two SPST switches would do the job, and you can get two of them in a one-gang unit - so it looks kinda like one switch, in a way.

Thanks for the pointer to those dimmable LED strings - didn't realize those were available. I'll suggest it - looks like it's the way to go.
 
RustyShackleford said:
Thanks guys.

That Carson switch (the 3A254) is close, but the HI setting would have to energize the red & blue wires - no way to do that without some logic or relays or something.

Yes, two SPST switches would do the job, and you can get two of them in a one-gang unit - so it looks kinda like one switch, in a way.

Thanks for the pointer to those dimmable LED strings - didn't realize those were available. I'll suggest it - looks like it's the way to go.
Click to expand...

You must use an led dimmer also.
 
I would use a stack switch with 1 single pole and 1 3-way configuration. He would only have low and high, but setup the single pole in series with the common terminal of the 3-way. Then connect each outlet to the traveler side of the 3-way.
 
mbednarik said:
I would use a stack switch with 1 single pole and 1 3-way configuration. He would only have low and high, but setup the single pole in series with the common terminal of the 3-way. Then connect each outlet to the traveler side of the 3-way.
Click to expand...
Neat idea. But the rope lights aren't very bright so probably want to be able to turn on all three strings; no way to wire this scheme to do that, even if "low" is one string and "high" is all three.

The idea of using that rotary switch mounted in the switch plate seems like a problem would be that its lead wires probably aren't 14ga. So it violates code against having less than 14ga on a 15amp circuit. Except that's done all the time, since most light fixtures, fans, etc have something like 16ga leads - dunno if the same rule that allows that applies to switches, but I doubt it.
 
RustyShackleford said:
Neat idea. But the rope lights aren't very bright so probably want to be able to turn on all three strings; no way to wire this scheme to do that, even if "low" is one string and "high" is all three.

The idea of using that rotary switch mounted in the switch plate seems like a problem would be that its lead wires probably aren't 14ga. So it violates code against having less than 14ga on a 15amp circuit. Except that's done all the time, since most light fixtures, fans, etc have something like 16ga leads - dunno if the same rule that allows that applies to switches, but I doubt it.
Click to expand...

You don't need to worry about the leads on the rotary dimmer. It is UL listed you the purpose. We cannot do that but they can since the load is limited by the dimmer.
 
Quick Google searched found similar products in the $7-$10 per foot range. I'm looking for around 1500' for a project so I presume the price for the tape will be lower for me. I should get pricing some time next week, but I will need the tape and power supplies to work with existing theatrical dimming in my application.
 
DTLight said:
Quick Google searched found similar products in the $7-$10 per foot range. I'm looking for around 1500' for a project so I presume the price for the tape will be lower for me. I should get pricing some time next week, but I will need the tape and power supplies to work with existing theatrical dimming in my application.
Click to expand...
Did you decide on a product yet ? From the ones I'm looking at, it looks the dimmer is in a cord that goes between the power-supply and the tape. I'm prefer to dim in the 120v domain, but not sure if that's possible or not. I don't even understand how LED dimming works; lowering the voltage doesn't work, it's gotta be the current, and they do not have a linear relationship for silicon generally.
 
RustyShackleford said:
Did you decide on a product yet ? From the ones I'm looking at, it looks the dimmer is in a cord that goes between the power-supply and the tape. I'm prefer to dim in the 120v domain, but not sure if that's possible or not. I don't even understand how LED dimming works; lowering the voltage doesn't work, it's gotta be the current, and they do not have a linear relationship for silicon generally.
Click to expand...

Pulse width modification is one way to 'dim' an LED. It's not really dimming them, it's turning them on and off real fast to give the effect of dimming.
 
G._S._Ohm said:
You can do even more.

50W on
100W on
both on by paralleling
both on in series
Click to expand...
Yeah, that's a neat idea - like an old 3-way incandescent bulb. Actually my original idea for how to accomplish this - and my OP question. I guess the inline dimmer cord could be used to set the brightnesses, and then the two wall switches (or the one switch that accomplishes the same thing, per my original question) for everyday changes in brightness.
 
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