In article , walter wrote:

As my 4 foot T12 fluorescent lights in my shoplights fail, can I replace
them with 4' T8 tubes? These shoplights all seem to have electronic
ballasts, consisting of a small, sealed plastic package about 2"x2"x1/2".

A T12 ballast may fail to start T8 tubes. If the T8 tubes start on the
T12 ballast, they will very likely be overpowered.

If you are going to use T8 tubes, then you need to replace the ballasts
- or, maybe more easily, the whole fixtures.

Then again, T12 full-40-watt tubes are not being completely banned.
There is an exception for ones with color rendering index above some
certain amount.

The only exempt-on-CRI ones that I know of, without compromise in light
output, are Philips "Ultralume" series. Last time I checked, Home Depot
had those. The 4100 color one is the same color as regular cool white.
--
- Don Klipstein )