paranoid_android said:We have been doing this very thing at work for months now. I think our total count to date is close to 12,000 lamps changed.
There is no hard and fast rule for determining compatibility before hand, we put them in and see what happens. I’ve put T8 size led lamps in a T12 ballast fixture and they worked fine, but some haven’t. We get to some fixtures with T8 fluorescents that won’t light and seem to have bad ballasts- put the leds in and they work fine as they are.
As for what you may want, I’d look for “hybrid” led lamps. They can work with or without a ballast so you can go either way- strip all the ballasts and direct wire, or replace ballasts to get them to work.
The one consistent thing we’ve seen is if the ballast says “program start” on it, it prolly won’t work. Rapid start is a maybe. But instant start will. That’s all we are putting in now.
*Edit- if I were spending the money, I would go for the direct bypass solution (no ballast).
I would love to learn more about this from your experience. I have approximately 200 T8 fixtures with 4 bulbs/fixture where the tombstones are failing. I've had some employees almost get hit by dropping bulbs. We know we're already going to have to "visit" each fixture and either replace the tombstones & install 4 LED bulbs (but leave the existing ballasts) or, replace the entire fixture with a new LED fixture (but hopefully fewer fixtures required because they are brighter). I can't really model this as a "payback" event - because the "visit" is expensive - just to get the electrician on the scissors lift and up touching the tombstones is $XXX/light plus the cost of the hardware.
