All LEDs in House Flicker In Sync - PoCo No Help

[jaronbrass]

Troubleshooting a particularly interesting problem. As background, I'm an engineer and a Lutron-certified sales engineer. This issue is occurring in my primary residence, which I use to demonstrate Lutron's lighting and shading solutions to prospective customers. This issue is having an impact on my business since it's difficult to showcase the benefits of these technologies when they misbehave.

We built this house with a reasonably well-known builder in Texas last year. We occupied in late November. During one of our final walkthroughs, we noticed some intermittent (2-3 second) flickering on the builder-grade chandelier installed in our foyer. At the time, we reported it on the punch list, and the electrical contractors and our third-party home inspector found no issues.

We come to find out that ALL lights in the house flicker in sync, for about 2-3 seconds, and then stop. The time between flickering is random, but you can be in one room and observe the different circuits adjacent all flicker in sync.

House is serviced by Pedernales Electric Cooperative (PEC) with 200A service. Main panel is Eaton with BR breakers. 240V breakers for the dryer, AC, oven, and sub-panel (90A) live on the outside of the house. The interior sub-panel is also Eaton with BR PON breakers. Lighting/socket circuits are 15A with AFCI breakers per code. Other circuits are 20A with a mix of standard breakers or combination AFCI/GFCI breakers depending on the service area. Overall, interior wiring looks pretty good.

We've replaced all mechanical toggle switches in the house with Lutron RadioRA2 components. We're using RRD-HN6BRL hybrid keypads, RRD-6ND/10ND dimmers, RRD-PRO dimmers in a few spots (these will replace the 6/10ND over time), and RRD-8ANS switches for things like ceiling and exhaust fans. Tabletop lamps are connected to RRD-3PD dimmers. Neutrals are connected everywhere.

Bulbs are Cree CR6T retrofit downlights up to 1600 lumens. Cree A19/A21 bulbs in screw-in fixtures. We yanked everything builder grade.

I have used this setup for years now. Bulbs are on Lutron's compatibility lists. Dimmers are trimmed properly. This has never been a problematic scenario except for here.

The flicker happens across ALL lights, whether downlights, sconces or plugged into sockets, in sync. Lights plugged into sockets will flicker with or without the plug-in dimmer module.

We've had a string of electricians out to diagnose. None can find fault with any inside wiring, although none have actually opened anything up to take a look. They keep blaming the Lutron gear and ignoring that this was an issue long before any retrofit work was done.

The power company has also been out multiple times. They found loose connections in various areas on their side of the main panel and supposedly tightened everything.

In total, the PoCo:
- bypassed their smart meter for about 8 hours and lights still flickered
- tightened connections and lights still flickered
- installed a voltage recorder and power quality monitoring equipment for 3 days

The PoCo has tried to blame EMF from our city's smart water meters, but I'm not buying it.

The data from the voltage recorder is interesting. They observed momentary 100A+ on one leg at roughly 5-minute intervals. They can't explain what it is. Neither can any electrician. The house is a natural gas house with 2 gas water heaters, gas furnace, gas range, etc. There's nothing installed that should cause that kind of reading. Which makes me wonder how accurate the data is.

So now the question... are these related? Or two separate issues? What should we be looking for? The neighbors we do NOT share a transformer with said their lights were flickering, and the builder replaced the bulbs, and the problem appears to have gone away... but they are not using dimmers like we are, which exacerbates the flickering. The house we do share a transformer with is also new and for sale, but I haven't spent enough time in it to determine if the problem exists there, too.

I'm attaching the power company data. This was captured in January. We were using heat at the time - no AC.

PoCo has basically washed their hands of this, but I'm hoping experts can weigh in. The voltage on the last page does seem to fluctuate more than I've seen in other homes.

I appreciate any insight.

 

[synchro]

When you say the utility bypassed the smart meter, did they remove it from the meter socket? Or did they somehow jumper it but leave it in place?

What you describe sounds like it could be due to TWACS signaling on an Aclara smart meter. The meter transmits inbound data by drawing relatively large current pulses to shift the zero crossings of the AC waveform. I think 100A short pulses might be typical.

 

[jaronbrass]

When you say the utility bypassed the smart meter, did they remove it from the meter socket? Or did they somehow jumper it but leave it in place?

What you describe sounds like it could be due to TWACS signaling on an Aclara smart meter. The meter transmits inbound data by drawing relatively large current pulses to shift the zero crossings of the AC waveform. I think 100A short pulses might be typical.

Yes, it was physically removed from the meter socket and replaced with a jumper. The PoCo tech and I were pretty disappointed it did not solve the issue. They've seen (I'm assuming) what you described in other installations.

 

[gar]

230417-0505 EDT

Start a new post without those plots. They put an extreme time burden on read this thread.

Then start trouble shooting by taking one of your bulbs somewhere else. My experience with CREE 9.5 W 120 V bulbs is that they are very good with either phase shift or Variac dimming. When you have a bulb that in another location shows no problem under substantial variations, then consider it a good test device.

Your voltage and current measurement system needs to be changed.

Some sample plots can be seen at my web site --- http://beta-a2.com/EE-photos.html ---- see plots P1 thru P4, and P26 thru P30. These don't directly relate to your problem, but illustrate a density that can be studied for the purpose at hand.

I will not be coming back to this thread.

.

.

 

[winnie]

Is the visual flicker synchronous with the high current spikes?

Can you get an oscilloscope trace downstream of a dimmer when flicker is occurring?

Jon

 

[synchro]

The neighbors we do NOT share a transformer with said their lights were flickering, and the builder replaced the bulbs, and the problem appears to have gone away... but they are not using dimmers like we are, which exacerbates the flickering. The house we do share a transformer with is also new and for sale, but I haven't spent enough time in it to determine if the problem exists there, too.

Yes, it was physically removed from the meter socket and replaced with a jumper. The PoCo tech and I were pretty disappointed it did not solve the issue. They've seen (I'm assuming) what you described in other installations.

There is probably a smart meter on the other house that is drawing current pulses from your shared trransformer, and that is modulating the voltage waveform at your house as well. Pulling your meter might have reduced how often the flickering occurs, but it would still happen if the neighbors meter was transmitting.

The following short video shows an oscilloscope waveform of TWACS signalling and resulting flickering. Apparently the same POCO as yours was involved.

 

[jaronbrass]

There is probably a smart meter on the other house that is drawing current pulses from your shared trransformer, and that is modulating the voltage waveform at your house as well. Pulling your meter might have reduced how often the flickering occurs, but it would still happen if the neighbors meter was transmitting.

The following short video shows an oscilloscope waveform of TWACS signalling and resulting flickering. Apparently the same POCO as yours was involved.

This is amazing. Thank you for sharing. And yep, it is the same power company PEC.

For us, the flickering duration is around 2-3 seconds, far less than in this video. It happens at all hours, day and night, at completely random intervals. Sometimes, it'll happen again in a matter of seconds. Other times, it could be a few minutes - or longer. And like a car mechanic, it rarely happens when PEC or other electricians are here. It affects every lamp in unison. I can be standing in the living room (central point of the house) and observe flickering across 6 different circuits simultaneously.

Power company has ruled themselves out (they're VERY stubborn and proud of their infrastructure) but I'm not so sure. It's getting them to dig deeper that is frustrating.

 

[jaronbrass]

Is the visual flicker synchronous with the high current spikes?

Can you get an oscilloscope trace downstream of a dimmer when flicker is occurring?

Jon

I have not confirmed yet if they are. Lights flicker 2-3 seconds at random intervals. Those intervals are sometimes shorter, sometimes longer. It does not appear to correlate to the charts the power company provided. I'm wondering if there are 2 issues and whether they're related or not. The TWACS issue pointed out above may explain the spikes. The power company has not answered how often the smart meter "phones home".

 

[zbang]

Just perchance, is there an airport or base nearby? Occasionally mis-aimed radar can do weird things. (Got some other thoughts, but they require more rereading and thinking.)

 

[tortuga]

We've had a string of electricians out to diagnose. None can find fault with any inside wiring, although none have actually opened anything up to take a look.

I appreciate any insight.

I'd reschedule with one for a 'paid consultation', that way they will actually take their tool bag out of the truck and open things up. These things can be hard to track down, but you'll never know unless a pro opens up stuff.

 

[synchro]

It's conceivable,but no means certain, that a constant voltage transformer could reduce the flickering. If you're willing to experiment, there are some cheap ones on Ebay in relatively small kVA ratings. You'd want a type CVS or "harmonic neutralized" one that has a sine wave output, and not a type CVN with a square wave output. You could try it out just feeding a dimmer and a single LED light to see what it does.
Constant voltage transformers are inefficient but can be effective.

Of course a good dual conversion UPS should prevent the flickering, but that's a bigger investment.

I seem to remember reading that someone was successful in getting a POCO to program the TWACS operation so that it didn't request transmissions from the smart meter during certain times.

 

[tortuga]

It's conceivable,but no means certain, that a constant voltage transformer could reduce the flickering. If you're willing to experiment, there are some cheap ones on Ebay in relatively small kVA ratings. You'd want a type CVS or "harmonic neutralized" one that has a sine wave output, and not a type CVN with a square wave output. You could try it out just feeding a dimmer and a single LED light to see what it does.
Constant voltage transformers are inefficient but can be effective.

Of course a good dual conversion UPS should prevent the flickering, but that's a bigger investment.

I seem to remember reading that someone was successful in getting a POCO to program the TWACS operation so that it didn't request transmissions from the smart meter during certain times.

What about a adding a capacitor? like the ones used for power-factor correction?

 

[synchro]

What about a adding a capacitor? like the ones used for power-factor correction?

Such a capacitor might help. A constant voltage (aka ferroresonant) transformer has a capacitor that resonates with the transformer's inductance. I suspect it would likely be more effective on the TWACS than a capacitor alone, but only testing would tell for sure.

 

[mtnelect]

The problem I encountered was with chandler style LED lamps. Used the "Scientific" method, changed everything out. My conclusion is that the base is to small for proper filtering.

 

[jaronbrass]

The problem I encountered was with chandler style LED lamps. Used the "Scientific" method, changed everything out. My conclusion is that the base is to small for proper filtering.

Those are almost always crap. These are E26 base bulbs and retrofit downlight fixtures with the same base, or the newer LED connector in some of the downlights we added.

 

[jaronbrass]

Any experience with something like this per the above suggestions?

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[curt swartz]

Any experience with something like this per the above suggestions?

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100% scam.

Unfortunately I don't have any suggestions that will help you.

 

[tortuga]

We've had a string of electricians out to diagnose. None can find fault with any inside wiring, although none have actually opened anything up to take a look.

I don't think we can be of more assistance here until a licensed electrician gets his or her tools out of the van and looks over your install.
We cant give DIY advice.

They keep blaming the Lutron gear

I often troubleshoot flickering issues, and one of the things I do is install regular switches and incandescent lamps for testing. I don't blame the gear unless I have good reason to, but I do remove it for testing.
I personally think you need to add a new electrician to your string of electricians.

 

[synchro]

Any experience with something like this per the above suggestions?

Power Perfect Box - Whole Home Dirty Electricity Filter, Surge Protector & Cost Saver! (Super Duty over 3000 sq ft)

Whole Home Dirty Electricity Filter. Save 15% on electricity. Surge protection, voltage regulation, line conditioning, harmonics reduction, equipment longevity.

emfessentials.com

I agree with Curt that it's a scam. When they mention "negative harmonics", the only similar thing I know of is negative sequence harmonics, and that only applies to 3-phase systems. It's notable that they don't give any meaningful performance specs supporting their claims.

What TWACS does to the AC waveform is not a surge to a larger voltage, but a narrow notch going down to a lower voltage due to a short duration ~100A pulse of load current. And then there can be ringing due to the source inductance and capacitance. Also, since the pulses are sending data they are not the same from cycle to cycle, which can end up jittering the waveform and causing flicker. A surge arrester is not going to do anything for that.
This is why I suggested trying a small constant voltage transformer, since the energy stored in its resonant inductance and capacitance may be able to "ride out" a notch in the voltage. But the nonperiodic nature of the data transmitted may still cause some amount of jitter. Only testing with LED lights can tell if a constant voltage transformer would do any good in this situation.

 

[Flicker Index]

There are one-way power line carrier signal blocking filters intended to improve communication clarity between different systems.
Say you and a neighbor sharing the same transformer both use the same type of power line carrier based home automation. if you install a blocking filter, it reduces the interference to your system from their system.

Perhaps such a filter could be put ahead of LEDs in question and see if that makes any difference.

Advanced Intelligent Control.

https://romvchvlcomm.pbworks.com/f/C045-P0597.pdf