Fan Control Switch Causing Lights to Flicker

[DBoone]

The switch is a Lutron TGFSQ-FH-WH

Toggle switch with the slide control on the side.

New construction home I am almost finished building, we have a lighting circuit that has Great Room cans, Kitchen cans, back porch fans. There are some other lights on it too but these 3 are where the issue is.

Great Room cans and Kitchen cans are each on a 3-way

There are two fans on the back porch and each is control by its own switch. There are no light kits on them. Fan only.

We put one Lutron dimmer for each group of can lights and they work great. No problems. Homeowner decided he would like to be able to control the fan speed from the switch location instead of the pull chain so we installed a Lutron fan control for each fan.

When sliding the speed control up and down the kitchen can lights Will slightly flicker/pulse.

Interference between the electronics of the dimmer switch and fan switch?

 

[DBoone]

 

[tshea]

Following. Have the same problem in a residential bathroom. Fan speed controls on the vent fans cause the lights to flicker. Fan and lights are on same circuit.

 

[ptonsparky]

Install a snubber.

 

[FionaZuppa]

Darn harmonics. Scope the line (the proper way) with FFT function, watch the fun.

My guess is, you have two sets of electronics, one in switch and one in the fan. You left fan on "hi" setting and want to limit speed by switch? Yeah, probably an inductance/capacitance thing going on there, but it's probably the fan stuff creating harmonics on the line.