If the lighting was built before 1980, you have to pay close attention to it. Most older light ballasts may have contained polychlorinated biphenyls (also referred to as PCBs).
If a ballast has gone bad or stopped working, it’s going to show several symptoms.These are the things to watch out for:– Light flickering– Buzzing noises– Low light output– Inconsistent lighting– Delayed lighting after being switched on