Q - What does Brownout mean
A - Brownout – the original use was when the normal (utility power) voltage dipped down to a point that the old fluorescent ballast could not operate the fluorescent lamp. Incandescent fixtures would still operate, but not the fluorescent fixtures. So there would be a partial loss of light, and it would be a brownout (some lights off) rather than a blackout (all lights off). The typical voltage dip that would cause the fluorescent fixtures to drop out varies between 70% and 80% of nominal. I have heard some people in the lighting and electrical industry use the term brownout and complete loss of normal utility power interchangeable.