Do 3-way X10 Switches Need A Load To Operate Properly?

Are you saying the motion sensor is only being supplied with 87vac? What is the voltage range rating of the fixture? What does the manual say about using a dimmer with the fixture?

My first reaction would be that there should be no dimmer in the circuit.

I think the general answer is that many of those types of devices need a load to function correctly. The key is if they require a neutral or not. With a neutral, they can be powered with no load at all. Without, they rely on the load to complete the circuit and power the X10 or similar electronics.

I believe code may now require a neutral in switch boxes? Not sure on that, but it would be a good idea going forward. Problem with all that X10 stuff is that it's not great quality, I don't think anyone is putting out any new, improved stuff, etc. I had a case where an X10 module worked perfectly for a couple years, then just stopped working. That module would work at other outlets, but not where it was. Nothing had apparently changed, no new electronic devices, anything to account for it. I spent a lot of time trying to figure it out and could not get it to work again. My approach now to X10 is if you have a simple app and can try it out for a few bucks it's OK. But I would not use it for a whole house automation system, anything critical, anything where you want a future, etc.

I was actually curious about this, so I found the manual:

It didn't have the technical information, so I called the customer service number and was told, categorically, the unit is incompatible with a dimmer and using a dimmer would dramatically shorten the life of the motion sensor, which is logical.

I am certainly familiar with the flakiness of X10 components. In this case, all I am using are X10 switches wired in as you would any normal switch. There are no control modules or X10 motion sensors or any of the stuff that usually causes issues. The switches were used mainly to take advantage of the dimming feature which is not a necessity, just nice to have. I may just get rid of them and eliminate that variable.

Stormin' Norman posted for all of us...

I wish DD would have done this.

Thank you for doing that research.

re: "dramatically shorten the life of the motion sensor"

That would be a helpful comment if one knew the normal life expectancy of the motion sensor. Shortening a 20 year life to 10 is very different than shortening a 3 year life to 1.

As I mentioned in my OP, the front door fixture has not had a problem in 5 years while being controlled by a single X10 dimmer switch. The garage fixtures have never lasted more than 18 months. They are both dimmed to the same level with the only difference being the use of two 3-way X10 switches, instead of the single switch.

X-10 dimmers do not just reduce the voltage. They adjust the duty cycle of the output. (Most modern dimmers work that way). The voltage read by your volt meter depends on how it reacts to strangely shaped waveforms. It may average 87 volts, but if you use an scope to look at it, you will not see a nice 87 volt sine wave. A $300 true RMS meter will do a lot better than a cheap VOM that assumes it is looking at a clean sine wave. Regardless, there is no way you should be feeding that signal to a motion detector. I am surprised it worked at all. To answer your question #1, the x-10 modules do not need a load to operate, but you can't really tell if they are operating with just a simple volt meter.

The point was, the manufacturers representative looked it up and said it was not designed, rated or intended to be used with a dimmer. In that case, why would the manufacturer test it with a dimmer just to determine how much shorter the life would be? Additionally, he also told me use of a dimmer invalidates the warranty.

They should have included all this information in the manual. Feel free to call and confirm what I told you, the number is printed in the manual.

If you wish to continue using them with a dimmer, knock yourself out. IMHO, the logical thing to do would be to eliminate the dimmer and simply use a lower power bulb.

Can't tell about yours without knowing if your wiring has a neutral at the switchbox AND fixture. IOW, some do and some don't. Add to that there's no telling how the system will react if the fixture interacts with X-10 or doesn't like having its power "chopped" by the thyristor in the X-10 switch.

I've had a similar motion sensor fixture running for over 15 years, first with incandescent, then with CFL's and now with LEDs. I control them with an appliance module because starting with the CFLs they would not work reliably with dimmable modules. Obviously dimming is not critical to me. I use incandescent bulbs when dimmability is important and where the circuit just won't work without a tungsten filament to carry trickle current to the X-10 device for the load.

For motion sensing I use the X-10 outdoor sensor modules with lithium cells and careful placement to avoid falsing. That sometimes means mounting them as you might an IR beam "breaker" detector and even masking them with electrical tape to limit their view. One hard to reach one is wired to a two "D" cell battery pack that's been running since 2004. I usually get 2+ years out of AAA lithiums so I suspect that the "D" cells are reaching the end of their service life. (-: The sensor activates the battery powered Robodog which will bark even if there's a power failure.

fixtures in 5 years?" (That's not really a question looking for an

Is there a substantial difference in placement? Is one more protected from the elements like sun and rain than the other? Does one spend more time being dimmed than the other? Electronics like those found in "smart" lighting fixtures don't seem to like being fed from a thyristor controlled dimmer that I believe is found in the X-10 three-way.

That would seem likely but if the garage fixture is exposed to direct rain or long periods of sun or is dimmed more frequently than the front door that could explain the frequent failures. Manufacturers idea of "waterproof" vary widely and lots of outdoor electronics need additional silicone sealant to keep out moisture. Allegedly "weatherproof" outdoor outlet boxes are a prime offender. Condensation can also occur more frequently in one fixture than the other. Need more site detail to know better.

An X10 switch can be wired in like a "normal switch", but it's not a normal switch. It has electronics in it that need to be powered up, ie a powerline receiver and SCR that acts as the switch. It needs a load like a lamp to complete the circuit for it to work.

But I agree with SN, I wasn't paying attention to the rest of it. Any fixture that has a motion sensor in it or other electronics of it's own, isn't likely to want to work with a dimmer.

That's not what I meant. I know that X10 switches are not "normal switches". I mentioned the switch wiring only in response to your comments about "modules at other outlets" to point out that there are no appliance modules or other X10 components in use. Just the switches wired directly to the fixtures.

This is getting to be fun. ;-)

You say it needs a load. Pat says it doesn't. Robert says it depends on the wiring.

Well, that just about covers it from all sides. ;-)

And yet, I'm going on 5 years with one fixture on an X10 dimmer and get about 18 months on average in the second location, also on a X10 dimmer.

In any case, I will be removing them and we'll see what happens, but you'll have to wait a year or so before we really know.

I don't know about everyone else, but I will be waiting with bated breath to learn if your problem has been solved........

No neutrals at the switches.

I've used the X10 sensors but could never find a reliable location for both the sensor and the module it controlled. When there was a problem it was typically split 20% - 80%. 20% of the time the sensor would not tell the module to come on. The other 80% of the time, the sensor would never tell to module to turn off - or perhaps the module just refused to listen. I gave up on X10 motion sensors years ago.

Are you saying that the dimmer in the 3-way is different than the dimmer in the "single" X10 switch? That might be the explanation for the fixture failures.

No difference in placement that I think matters. They are both under the same overhang along the front of the house, maybe 25 feet apart. They are both dimmed to same level, which doesn't get changed. The one that has lasted for 5 years is by the front door and comes on substantially more often than the ones that fail. Every time we open the door for any reason (mail, cat, paper, etc.) that light comes on. The garage light only comes on when we walk near it.

you might consider opening one of the failed units to see if it shows signs of corrosion or that the magic smoke came out of a component or what?

And that's 87 vac with a chopped waveform that can interact badly (or at least oddly) with the switched power supply that's very likely in the floodlight fixture to power the motion sensing circuitry.

"Not for use with dimmer switched circuits?" (-:

Seriously, scroll down to the ratings and reviews and the unti gets just 37% approval with the lead comments being "Poor quality . . . total junk . . . stopped working after a month" etc.

Nothing I could find about any warning but I do recall buying similar items that said "not for use on dimmer circuits."

After reading the reviews it's I think the items are dying from inherent vice. But if it's been extensively dimmed and the other fixture hasn't, there's food for thought about that being the cause. Still, I would expect underpowering a unit to cause flaky performance and not premature system failure.

"Stormin' Norman" wrote in

Good point.

Hmm. Information absent from the Lowe's site. Critical information, I would say.

DD's conundrum is an all-too familiar one with X-10. A lot of people want remotely dimmable exterior motion sensor lighting.

But X-10 was designed when there really wasn't anything in a screw-in base that didn't allow trickle current to power the X-10 device. That's clearly no longer the case.

The problem may not be curable without rewiring or sacrificing dimming. I am quite surprised his setup works at all but there are a lot of different circuits in motion detector lamps. The dimmer incompatibility issue is clearly one they are aware of. They might have even developed circuits that can work reliable from the output of a thyristor circuit.

Still, I don't see a mechanism where under-voltage will damage it. True in motors but not simple circuits like these. They should just either refuse to work or behave erratically.

Trader was right. I forgot about powering the X-10 module itself when I answered. Most x-10 modules need some sort of load to power themselves. I vaguely remember a few x-10 compatible modules that used the neutral but most did not.

Regarding three way, are both of your x-10 switches identical? (I know one is connected in a 3-way and the other isn't, but are they the same model?) Maybe a minor design difference is affecting the waveform powering the motion detector. Just guessing. Pat

After skimming through the responses, I'd say you need an X10 wall switch module. I use one to control a 12 volt power supply which runs a strip of LED light under the upper kitchen cabinets. It is basically an appliance module and has a relay to turn on the load. If you want a dimmer light, get a smaller bulb. On the one that continues to work, it is might have slightly different electronics inside or the dimmer setting is different, but either way, it's not a good idea to "dim" another piece of electronics.

I am curious, why would one need an X10 wall switch module for a motion sensor light?

The manual indicates the device is supposed to remain powered on continually. If the only time you need to interrupt power is when you wish to manually override the motion sensor, why not just use a standard light switch?

In this application, an X10 seems unnecessarily gimmicky to me.