AFCI Breaker w/ Z-Wave Switches

I’ve installed HomeSeer HS-WD100+ and HS-WS100+ switches in my house. They work perfectly for the most part. In my master bedroom I also have a GE Fan controller switch (12730) - I chose this to match the other switches, and I suppose you can’t use a HS-WD100+ for the fan, even though the GE seems to work identically.

In the master bedroom the fan light and lamp pulse for 10-15 seconds every 60 seconds or so. I have double checked my neutral connections to make sure they were secure. I bought a multimeter and observed that while the pulsing occurs the voltage alternates between 120 and 117.

I have a Keurig plugged in on the same circuit, and curiously it doesn’t happen when I have that unplugged, but the alternation in voltage still happens, just at 121 and 119/120. On every other circuit the voltage stays constant.

Since the alternation happens on every plug on the circuit, I ruled out a wiring issue with the Z-Wave switches themselves. Those are at the end of the circuit. And I have verified every plug is wired correctly.

I had a retired electrician come over (a friend) and he found what he thought was a CGCI breaker on the bedroom, which he thought was odd. After doing some of my own research, I’m fairly certain they are actually AFCI breakers, which are required in bedrooms starting 2014.

So it seems like the wiring is correct and the breakers are correct. So I’m left with three possibilities:

1 - The HomeSeer switches are not compatible with AFCI.
2 - The GE switch is not compatible with AFCI.
3 - The Cree LED bulbs (dimmable, newer model I believe) are not compatible with AFCI.

W/ the first 2 I’ve read that Lutron had some sort of filter for their dimmers.

The guest bedrooms share an AFCI breaker (I use one as an office), and I’ve observed the lights slightly dim when I turn the computer on.

I don’t have any of these issues on the other circuits which have standard breakers.

So far I’ve thought of disconnecting the GE fan controller and see if that makes a difference. The HomeSeer dimmer. And last (or first?) try a different brand of LED bulb (Phillips?).

Does anyone have any other suggestions?

Before going further, just wanted to check and make sure that the lightbulbs are dumb lightbulbs, correct? You’re not trying to control the current to a smart bulb with a Z wave dimmer.

Correct. Just regular (dim compatible) Cree bulbs.

I believe these are what I got ($10 for a 4-pack at the time):

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I have several GE and Linear z-wave switches and almost my entire house is covered by D-square AFCI breakers and I don’t have these issues. My LED disk lights occasionally flicker, but no pulsing like you describe.

AFCI breakers are a pita though. We can’t run our vacuum on them without tripping. Have to plug it in bathroom outlets where they are GFCI only. When i was researching that i read all sorts of anomalies with AFCI breakers.

Maybe @Navat604 or @dalec or one of the other electrical experts will have some ideas.

AFCI and motor is not a good combo unless all the wiring and fan are in good shape. Fan vibrates which could cause loose wiring or worn motor will cause the AFCI to trip but the alternating is most likely cause by your fan motor. You can disconnect the fan load wire at the switch, cap it and turn it on. No alternating? Then it’s the fan.
If you suspect the switch. Then disconnect the line wire to the switch. Cap it. Turn it on and test.

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The fan is off when the alternating occurs. Could it still be the fan if it is off? I’ve also turned the light dimmer off w/ the Lamp on (binary switch), and vise versa. I’ll definitely try capping line/load though.

Do you know if AFCI has any issues w/ a computer on the circuit? The lights dim when the computer is first turned on (in the guest bedroom).

I should also mention the AFCI breakers are 15 amp.

I don’t think this is an issue with AFCI. As long as the breaker is not tripping then it’s not a loose wire problem unless the AFCI is installed incorrectly and can’t detect arcing.
First thing I would do is unplugging and turning all the equipments connecting to that circuit and see if the problem still there.
You can test the AFCI breaker by pressing the test button and look at the indicator or ask your electrician friend to swap the wire with the breaker beside it.
Just like a hair dryer. The light will dim for the initial start caused by the high current draw so it’s not an issue unless the lights stay at dim when the computer is up and running.
The only way to be sure if the fan is out of the circuit is by disconnecting the line wire of the switch. This will eliminate both the switch and fan from the circuit.
Instead of using the neutral. Put your meter test probe on ground and line. Is the alternating still there? This test is to be sure you don’t have a loose neutral and a bad AFCI.
AFCI is a pain but it’s also a life saver just like smoke detector.

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This is very interesting issue for it to be pulsing with the motor off so I would say the motor is ruled out for now. Is it possible for you to upload a quick video of the problem in action? I am interested in looking at the frequency of the pulse to get an idea of what might be causing it. But I would follow @Navat604 advice and start removing everything that is on that circuit and have it “clean” to see if the pulse is still there then slowly add one at a time till you identify the culprit. If it still exists with everything unplugged then it is time to disconnect the fan motor. Something on that circuit is inducing the problem since your other circuits are unaffected.


When I unplug everything (TV, Keurig, Robot vacuum) the pulsing no longer occurs, however the voltage still fluctuates, just at a higher range - 121-119. With those things plugged in the range is 120-117, at which point the bulbs pulse. And this occurs w/ either or both lights on, and with the overhead light at 100% brightness or lower.

When I test the voltage I’m testing the plugs between line and neutral. I haven’t tested between line and ground yet.

If I had to guess, the pulsing is about 20ms. It’s fast, but fast enough to perceive and be annoying. And it occurs only for 5-10 seconds every minute or so. Timing isn’t exact, but regular. And when I test the voltage, the alternation is slower than the pulsing itself (like 10x), but I’m not sure if that’s just because of the multimeter I have (which is set to 600w - has a 200w option for higher resolution).

I’ll be able to do some more testing when I get home.

Just to be clear, you are talking about pulsing and not flickering light right? Can you put in an incandescent bulb to confirm it’s pulsing and not flicking caused by LED and dimmer?
Your house voltage could fluctuate anywhere between 110 to 120v depend on your provider and your house so I wouldn’t worry about a couple of volts fluctuating but the pulse is a problem caused by something else for sure.

Well there ya go then! You just need to plug “those things” in one at a time to see who the culprit is. Sounds now like you are getting a possible single phase harmonics problem being induced by one or all of “those things”. Not that you are asking but why not give you a wiki link to read up a little if you are interested as well as this one.

Light emitted from the LED bulbs appear to be pulsing on/off very quickly. I guess you could consider that a flicker? It happens on a regular basis, almost exactly for 10 seconds every 60 seconds. It’s not exact, but close to that.

When I say the voltage fluctuates, I can see the number changing back and form 120 to 118-117 continually with no other device being turned on. On my other non-AFCI circuits I will read 120 continually. If I turn something on that uses a lot of power (like a computer), it drops to 118 but holds there. Whereas the AFCI circuit in the bedroom will continually go up and down, in tandem with the pulsing/flickering lights.

The HomeSeer Z-Wave dimmers are supposed to be compatible with LED dimmable bulbs. I have the same dimmers and bulbs on other circuits in the house, and those work without any issues.

@dalec, when I unplug everything (besides the light switches), I still have the harmonics problem, just a higher voltage. Which if that’s true means the bulbs are sensitive to that at lower voltages, right? The problem is still there, just isn’t perceivable.

If everything is unplugged, I shouldn’t have a harmonics problem, right?

Not very relevant, but similar issue. I have a Breville toaster over, more like a small oven and expensive. It causes a similar flicker in some LED’s anywhere within the house, any circuit.

It was more noticeable on the 1st generation LED’s and non-existent on some of the newer ones, including GE and Cree smart bulbs.

I have 4 candelabra base in the bath though and it’s very annoying.

It’s a flicker issue. You have two options. Change the bulbs or the dimmer. Unfortunately, there is no easy way out. You can swap out your smart switch with a dumb one to test the circuit or put in one incandescent bulb to see if all the bulbs stop flickering. By installing one incandescent. You induce a voltage delay on an off cycle. This will confirm it’s a dimmer issue if the flickering stop.

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Just wanted to add that there are at least five factors in any flicker issue:

The bulb

The fixture

The wiring

The load on the circuit

The switch

This is why a switch/bulb combination which works fine in one room might flicker in another.


And I suppose it could be a combination of those things, right?

What’s odd about this is:

  • Both lights flicker. The ceiling fan light and the lamp. At the same time.
  • The lamp doesn’t flicker on a different plug on another circuit.
  • I have the same bulbs and switches on other circuits that work fine.
  • I have the same GE fan control and dimmer on another circuit downstairs that works fine. But it’s not on an AFCI breaker.

Which leads me to believe it’s either:

  • A wiring issue (between breaker and first plug?)
  • An issue with that particular switches (not the model)
  • The ceiling fan light/fan
  • The AFCI breaker

I can’t wait to get home and diagnose this further :smiley:. I’ll let you guys know what I find :joy:

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