I'd start by turning off the circuits that were worked on and see if the lighting still strobes.

Here's the explanation:

Did you replace the lamps (light bulbs) in the fixtures controlled by the dimmers as part of the electrical work? Maybe upgrade to LED?

I did replace the lights in one track with LED, and I've had extensive interaction with Lutron/LSI/SORAA on that. I have determined that I need MAELV-600 dimmers for these LEDs in my lights, although that track is actually working fine (aside from buzzing and some minimal flickering.)

But all of my tracks and recessed BESIDES the one with LEDs are the ones doing the strobing. All of those lights have the same halogen bulbs that were in there when I moved in and all was well. No changes.

Plus, this isn't flickering. This is full on/off strobing. Lights go all the way OFF, glide back up to wherever they were set, turn OFF, repeat. The LED track is NOT doing this.

So I have two basic questions:
(1) Can having magnetic( MALV) dimmers on fixtures that need MAELV (ie, have electronic transformers, Hatch RS12-60M in the tracks and LighTech in the recessed) cause full on and off strobing like this? That's the electrician's assertion, although he can't explain why it was fine before he worked and now isn't.
(2) How can I check for neutral interaction, per the above wonderful entry? Electrician swears he's checked it. I have two halls off my foyer, with two dimmers on the same breaker circuit. If you turn hall #1 on, and then hall #2 on, hall #1 goes off and then starts to flash. HAS to be neutral interaction, but how do I check for it?? I don't know how to ensure electrician has performed the test.

Many thanks.

The easy diagnosis would be to change the dimmers with toggles to see if it stops. That rules out any problems with the electrician's work. It establishes the dimmers are not "playing nice".

First of all, you need to have the correct dimmers - if you need electroic dimmers - get them. The 'system' needs to be to 'spec'.

Then, if there are still problems, remove the 'hot' wire from the sconces.

Geoffrey B (or anyone else)

I am now convinced that I have a common neutral on two phase wiring. HOW do I proceed with finding it?

How do I tell what's on what phase? If I have two phases in one junction box, how do tell the two phases apart?

Thanks

As I said: Since you don't have the correct dimmers - one cannot rule out that the dimmers are causing your problem.

Find the breaker for each of the new outlets. Turn one off - and see if the lighting problem goes away. Keeping the first one off, do the next and check the lights, and do the same for the third.

If that fails - then probably the hot wire to the sconces is on the other 120 volt side.

Thanks, I'll try that. Challenge is that it's somewhat intermittent.....hard to determine what sets it off, and then it tends to be localized to 1-2 dimmers on a single circuit.