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Flickering Plug-In Z-Wave Outlet Modules


This is a “case study” of flickering that I think I may have solved. I’m providing it as a possibly helpful case for other Z-Wave users.

I’ve been installing a combination of Z-Wave devices in our house: plug-in outlets, wall switches, wall dimmers, and outdoor plug-in outlets. I purchased Honeywell devices because my home security system is made by Honeywell and I thought it might be helpful to have a single manufacturer. The Z-Wave devices are manufactured by Jasco who also makes the GE Z-Wave devices. The plug-in outlet modules have table lamps plugged into them and all have conventional incandescent bulbs, not LED or CFL. Everything has been working rock-solid since I started the installation about a month ago.

Yesterday I was identifying circuit breakers using a Klein Tools “Digital Circuit Breaker Finder” Model ET300.

Last night, for the first time (after about a month of use), my plug-in outlets in the living room began acting wonky - initially one plug-in module would occasionally have a brief “flash” of brighter light. Things degraded to a more constant flickering, then spread to the other plug-in modules, and eventually the lights were going up and down in intensity (not synchronized) and constant flickering. Things would stabilize and be normal for a minute or two without flickering, then again start “flashing” and degrade again to flickering and wide variations of intensity.

I used my Fluke Digital Volt-Ohmmeter to measure voltage. I was getting a average of about 122 VAC with swings of about +/1 0.8 volts over a ten minute period, so nothing out of the ordinary was happening with the power supply. The only other loads in the house were the refrigerator and furnace.

A few minutes ago, I was talking to Jasco Support about the problem and found my circuit breaker legend/map didn’t identify one outlet. I went to use my Klein Circuit Breaker Finder and discovered I had left the transmitter plugged in since yesterday in an adjoining bedroom. I unplugged it there, plugged it into a living room outlet, and it caused the lamp plugged into that circuit to flash and flicker. I removed and re-inserted the transmitter and reproduced the flickering each time.

These circuit breaker finders “draw spikes of current off of the line—typically anywhere from 6-10 amps. It does this for a short duration, yielding a very strong signal. Because of this, the transmitter portion of this system is rather simplistic. There are no batteries, and it doesn’t really have to do much more than draw pulses of current that the receiver is designed to detect.” So, somehow, these brief current draws seem to be interfering with the Z-Wave plug-in outlet modules. Interestingly, my permanently installed Z-Wave switches and dimmers were not affected.

Obviously, you would not leave the circuit breaker finder transmitter permanently plugged in and it was my mistake to leave it plugged in last night (a mistake I won’t make again). Things seem to be normal this morning with the transmitter (properly) unplugged.

This is corner case that you will probably never experience, but be warned about the potential problem if you leave your circuit breaker finder plugged in. The Jasco customer service rep had not heard of this before and was going to add a note in their knowledge base.

Here are the products referenced above:

(Eric) #2

Thanks - this kind of practical issue is why I read here.

I’ve never used that kind of “toner” before. Does it have a deep range? 6amps, sheesh it’d better.


Eric, the "circuit breaker finder " (CBF) is not a classical telecom toner which superimposes a waveform signal over the 60 Hz AC line voltage. From what I’ve read, the CBF just draws momentary spikes of power. The CBF works on energized circuits. The toners work on AC wiring and telecom wiring, but the AC circuit must be de-energized. The toner is used to trace wires inside the wall; the CBF identifies the breaker controlling an outlet or a ceiling light socket. So you see they have different uses.

I have both. We bought a used house and this place has a large number of circuits, outlets, and light switches (including so e “half hot” outlets). I used the CBF to find out which breaker controlled which outlet. I used my toner to trace some wires in the wall. The sellers had disconnected a switch in the wall that controlled a half-hot outlet. It was just a “dead” disconnected switch sitting in the box. I was able to trace the wires and quickly find the controlled outlet without taking out six sockets in the room.

Whatever you do, don’t leave the CBF transmitter plugged in unless you like Z-Wave lights getting a mind of their own!