Last week I had an electrician in to put in some new wiring; I also had an HVAC guy come do the annual maintenance on our system. Since then, the lights in our living room flicker whenever the A/C comes on.
I would usually suspect the start-up capacitor in the compressor, but the compressor is on a separate panel from our living room lights. On the other hand the 1st floor lights (1) and the attic air handler (4-6) are on the same panel, as is the new wiring, which was added to the Bath GFCI circuit (2) as shown here:
The new wiring is supporting our basement de-humidifier and a desktop computer. I confess to knowing next to nothing about home electrical — is it possible that the additional current being drawn by circuit 2 could be causing the flickering of lights in circuit 1 whenever the HVAC kicks on?
Best Answer
Find out what the A/C guy did. I would guess he did something which improved the performance of the A/C system, so now, instead of the motor nearly freewheeling against little load, it's having to hunker down and really work. The increased amperage is "bringing to the surface" a pre-existing problem with wiring, probably between the sub-panel and the supply.
I would now measure to see how serious the problem really is. It may not be worth worrying about, it may just be over-sensitive bulbs.
You can mask the symptom by buying modern lamps. Any multi-voltage rated LED (typically 100-240V) or fluorescent tube ballast (100-277V) will ride through voltage sags. Avoid the cheapies (Feit, Utilitech, Lights of Amerchina, and CFLs of any make; you will not be satisfied with their long-term performance, and they will give LED a bad name.)