The basement is heated.
The fixtures are new, been in use 3 - 4 wks.
The fixtures replaced the existing pullchain fixtures that were originally installed in the cellar ceiling, when the house was built. Two circuits are on bedroom receptical circuits and the third is on the living room receptical circuits.
The ballast are not humming, but they get a little warm. Electrician said that was normal.
The Electrician verified the grounding at the fixtures and in all boxes all the way back to the panel. All was tight, but he replaced all connections anyway.
I verified the bulbs are correct, but I have not tried replacing them. I will try that this week.
Do you think the bulbs are the problem? Or could it be the ballasts? (I will try bulbs first, as there are cheaper.)